The rotations of cometary nuclei are known to change in response to outgassing torques. The nucleus of the Jupiter-family comet 41P/Tuttle–Giacobini–Kresak exhibited particularly dramatic rotational changes when near perihelion in 2017 April. Here, we use archival Hubble Space Telescope observations from 2017 December to study the postperihelion lightcurve of the nucleus and to assess the nucleus size. From both Hubble photometry and nongravitational acceleration measurements, we find a diminutive nucleus with effective radius r_n = 500 ± 100 m. Systematic optical variations are consistent with a two-peaked (i.e., rotationally symmetric) lightcurve with period 0.60 ± 0.01 days, substantially different from periods measured earlier in 2017. The spin of the nucleus likely reversed between perihelion in 2017 April and December as a result of the outgassing torque. We infer a dimensionless moment arm k_T = 0.013, about twice the median value in short-period comets. The lightcurve range of 0.4 mag indicates a projected nucleus axis ratio ≳1.4:1, while the active fraction of the nucleus decreased from ∼2.4 in 2001 (suggesting augmentation of the gas production by sublimating coma ice grains) to ∼0.14 in 2017, a result of long-term modification of the surface. We find that the physical lifetime of this small nucleus to spin up is short compared to the reported ∼1500 yr dynamical time spent in the current orbit. Two limiting reconciliations of this inequality are suggested. The nucleus could be in a state of unusually strong activity, leading us to overestimate the average mass-loss rate and outgassing torque and so to underestimate the physical lifetime. Alternatively, the nucleus could be the surviving remnant of a once larger body for which outgassing torques were less effective in changing the spin.

Recent discoveries of transiting giant exoplanets (R_p ≳ 8 R_⊕) around M dwarfs present an opportunity to investigate their atmospheric compositions and explore how such massive planets form around low-mass stars contrary to the prediction from formation models. We present the first transmission spectra of TOI-5205b, a short-period (P = 1.63 days) Jupiter-like planet (M_p = 1.08 M_J and R_p = 0.94 R_J) orbiting an M4 dwarf (M_⋆ = 0.392 M_⊙, R_⋆ = 0.394 R_⊙). We obtained three transits using the PRISM mode of the JWST Near Infrared Spectrograph spanning 0.6–5.3 μm. The data reveal significant stellar contamination that is evident in the light curves as spot-crossing events and in the transmission spectra as a larger transit depth at bluer wavelengths. Atmospheric retrievals demonstrate that stellar contamination from unocculted starspots and faculae is the dominant component of the transmission spectrum at wavelengths λ ≲ 3.0 μm, reducing the sensitivity to the presence of clouds or hazes in our models and preventing detection of H_2O. The wavelength coverage enabled a robust detection of CH₄ and H₂S, which have detectable molecular features between 3.0 and 5.0 μm. For both clear or cloudy atmospheres, Bayesian retrievals consistently favored an atmosphere with subsolar metallicity (3σ upper limit of ${\mathrm{log}}[{\rm{M}}/{\rm{H}}]\lesssim -1.24$) and supersolar C/O ratio (3σ lower limit of ${\mathrm{log}}[{\rm{C}}/{\rm{O}}]\gtrsim 0.09$), although this may partly be driven by the nondetection of water due to stellar contamination. Planetary interior models predict a bulk metallicity of 10%–20%, which is larger than the atmospheric metallicity and suggests that the interior of TOI-5205b is decoupled from its atmosphere.

Megaconstellations of thousands to tens of thousands of artificial satellites (satcons) are rapidly being developed and launched. These satcons will have negative consequences for observational astronomy research, and are poised to drastically interfere with naked-eye stargazing worldwide should mitigation efforts be unsuccessful. Here we provide predictions for the optical brightnesses and on-sky distributions of several satcons, including Starlink, OneWeb, Kuiper, and StarNet/GW, for a total of 65,000 satellites on their filed or predicted orbits. We develop a simple model of satellite reflectivity, which is calibrated using published Starlink observations. We use this model to estimate the visible magnitudes and on-sky distributions for these satellites as seen from different places on Earth, in different seasons, and different times of night. For latitudes near 50° north and south, satcon satellites make up a few percent of all visible point sources all night long near the summer solstice, as well as near sunrise and sunset on the equinoxes. Altering the satellites’ altitudes only changes the specific impacts of the problem. Without drastic reduction of the reflectivities, or significantly fewer total satellites in orbit, satcons will greatly change the night sky worldwide.

We present a rotational velocity ($v\sin i$) survey of 32 stellar/substellar objects and giant planets using Keck/KPIC high-resolution spectroscopy, including 6 giant planets (2–7 M_Jup) and 25 substellar/stellar companions (12–88 M_Jup). Adding companions with spin measurements from the literature, we construct a curated spin sample for 43 benchmark stellar/substellar companions and giant planets and 54 free-floating brown dwarfs and planetary mass objects. We compare their spins, parameterized as fractional breakup velocities at 10 Myr, assuming constant angular momentum evolution. We find the first clear evidence that giant planets exhibit distinct spins versus low-mass brown dwarf companions (10–40 M_Jup) at 4–4.5σ significance assuming inclinations aligned with their orbits, while under randomly oriented inclinations the significance is at 1.6–2.1σ. Our findings hold when considering various assumptions about planets, and the mass ratio below 0.8% gives a clean cut for rotation between giant planets and brown dwarf companions. The higher fractional breakup velocities of planets can be interpreted as less angular momentum loss through circumplanetary disk braking during the planet formation phase. Brown dwarf companions exhibit evidence of slower rotation compared to isolated brown dwarfs, while planets and planetary mass objects show similar spins. Finally, our analysis of specific angular momentum versus age of 221 stellar/substellar objects below 0.1 M_⊙ with spin measurements in the literature indicates that the substellar objects of 5–40 M_Jup retain much higher angular momenta compared to stellar and substellar objects of 40–100 M_Jup after 10 Myr, when their initial angular momenta were set.

Kepler-51 is a 500 Myr G dwarf hosting three “super-puffs” and one low-mass nontransiting planet. Kepler-51d, the coolest (T_eq ∼ 350 K) transiting planet in this system is also one of the lowest-density super-puffs known to date (ρ_p = 0.038 ± 0.009 g cm⁻³). With a planetary mass of M_p = 5.6 ± 1.2 M_⊕ and a radius of R_p = 9.32 ± 0.18 R_⊕, the observed properties of this planet are not readily explained by most planet formation theories. Hypotheses explaining Kepler-51d’s low density range from a substantial H/He envelope comprising >30% its mass, a high-altitude haze layer, to a tilted ring system. To test these hypotheses, we present the NIRSpec-PRISM 0.6–5.3 μm transmission spectrum of Kepler-51d observed by the James Webb Space Telescope. We find a spectrum best fit by a sloped line covering the entire wavelength range. Based on forward modeling and atmosphere retrievals, Kepler-51d likely possesses a low-metallicity atmosphere with high-altitude hazes of submicron particle sizes spanning pressures of 1–100 μbar. However, the spectrum could also be explained by a tilted ring with an estimated lifetime on the order of ∼0.1 Myr. We also investigate the stellar activity of this young Sun-like star, extracting a spot temperature significantly hotter than sunspots and spot covering fractions on the order of 0.1%–10% depending on assumed spot parameters.

Exploring the properties of exoplanets near or inside the radius valley provides insight on the transition from the rocky super-Earths to the larger, hydrogen-rich atmosphere mini-Neptunes. Here, we report the discovery of TOI-1452b, a transiting super-Earth (R_p = 1.67 ± 0.07 R_⊕) in an 11.1 day temperate orbit (T_eq = 326 ± 7 K) around the primary member (H = 10.0, T_eff = 3185 ± 50 K) of a nearby visual-binary M dwarf. The transits were first detected by the Transiting Exoplanet Survey Satellite, then successfully isolated between the two 32 companions with ground-based photometry from the Observatoire du Mont-Mégantic and MuSCAT3. The planetary nature of TOI-1452b was established through high-precision velocimetry with the near-infrared SPIRou spectropolarimeter as part of the ongoing SPIRou Legacy Survey. The measured planetary mass (4.8 ± 1.3 M_⊕) and inferred bulk density (${5.6}_{-1.6}^{+1.8}$ g cm⁻³) is suggestive of a rocky core surrounded by a volatile-rich envelope. More quantitatively, the mass and radius of TOI-1452b, combined with the stellar abundance of refractory elements (Fe, Mg, and Si) measured by SPIRou, is consistent with a core-mass fraction of 18% ± 6% and a water-mass fraction of ${22}_{-13}^{+21}$%. The water world candidate TOI-1452b is a prime target for future atmospheric characterization with JWST, featuring a transmission spectroscopy metric similar to other well-known temperate small planets such as LHS 1140b and K2-18 b. The system is located near Webb’s northern continuous viewing zone, implying that is can be followed at almost any moment of the year.

The planetary and lunar ephemerides called DE440 and DE441 have been generated by fitting numerically integrated orbits to ground-based and space-based observations. Compared to the previous general-purpose ephemerides DE430, seven years of new data have been added to compute DE440 and DE441, with improved dynamical models and data calibration. The orbit of Jupiter has improved substantially by fitting to the Juno radio range and Very Long Baseline Array (VLBA) data of the Juno spacecraft. The orbit of Saturn has been improved by radio range and VLBA data of the Cassini spacecraft, with improved estimation of the spacecraft orbit. The orbit of Pluto has been improved from use of stellar occultation data reduced against the Gaia star catalog. The ephemerides DE440 and DE441 are fit to the same data set, but DE441 assumes no damping between the lunar liquid core and the solid mantle, which avoids a divergence when integrated backward in time. Therefore, DE441 is less accurate than DE440 for the current century, but covers a much longer duration of years −13,200 to +17,191, compared to DE440 covering years 1550–2650.

We conducted a two-band imaging survey observation using the Subaru Telescope and its wide-field camera, Suprime-Cam, to study the visible colors and size distribution of Jupiter’s Trojan asteroids. The survey covered an area around Jupiter’s L4 Lagrange point totaling 9.2 square degrees. We detected 120 Trojan asteroids in this survey. From these Trojan asteroids, we extracted 44 unbiased samples with absolute magnitudes in the $g^{\prime}$ band ranging from 12.9 to 16.9 mag (corresponding to diameter ranges of approximately ∼3–16 km assuming an albedo of 0.05) and analyzed their $g^{\prime} -i^{\prime}$ color and size distributions. Large Jupiter Trojan asteroids are known to be classified into two color groups, “red” and “less red.” We found that such bimodality in the color distribution is absent for small Jupiter Trojan asteroids, which is consistent with previous studies. Previous studies have also shown that these two groups have different slopes in the magnitude distributions from each other, which was explained by conversion of red objects to less-red fragments through catastrophic disruptions. In contrast, we found that the size frequency distributions of our two sample groups divided by the color of $g^{\prime} -i^{\prime}$ = 0.7 (in AB magnitude) are quite similar. Our results can provide new insights into collisional evolution of color and size distribution of small Jupiter Trojans.

Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper Belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain this alignment, to date, a theoretical model that can successfully account for the observations remains elusive. In this work we show that the orbits of distant Kuiper Belt objects (KBOs) cluster not only in argument of perihelion, but also in physical space. We demonstrate that the perihelion positions and orbital planes of the objects are tightly confined and that such a clustering has only a probability of 0.007% to be due to chance, thus requiring a dynamical origin. We find that the observed orbital alignment can be maintained by a distant eccentric planet with mass ≳10 m_⊕ whose orbit lies in approximately the same plane as those of the distant KBOs, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed orbital alignment, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semimajor axis objects with inclinations between 60° and 150° whose origin was previously unclear. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing our hypothesis as well as further constraining the orbital elements and mass of the distant planet.

In this brief communication we provide the rationale for and the outcome of the International Astronomical Union (IAU) resolution vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015, on recommended nominal conversion constants for selected solar and planetary properties. The problem addressed by the resolution is a lack of established conversion constants between solar and planetary values and SI units: a missing standard has caused a proliferation of solar values (e.g., solar radius, solar irradiance, solar luminosity, solar effective temperature, and solar mass parameter) in the literature, with cited solar values typically based on best estimates at the time of paper writing. As precision of observations increases, a set of consistent values becomes increasingly important. To address this, an IAU Working Group on Nominal Units for Stellar and Planetary Astronomy formed in 2011, uniting experts from the solar, stellar, planetary, exoplanetary, and fundamental astronomy, as well as from general standards fields to converge on optimal values for nominal conversion constants. The effort resulted in the IAU 2015 Resolution B3, passed at the IAU General Assembly by a large majority. The resolution recommends the use of nominal solar and planetary values, which are by definition exact and are expressed in SI units. These nominal values should be understood as conversion factors only, not as the true solar/planetary properties or current best estimates. Authors and journal editors are urged to join in using the standard values set forth by this resolution in future work and publications to help minimize further confusion.

The rapid growth of imaging and spectroscopic surveys has intensified the need for efficient tools that support visual inspection, a practice that remains essential for tasks such as classification, catalog refinement, and validation of automated methods. Existing solutions, however, often require the use of multiple platforms and complex workflows to integrate heterogeneous data. To address this challenge, we present the first release of AstroInspect (https://astroinspect.github.io), a web-based system designed to ensure seamless access to several astronomical resources. The system provides an intuitive graphical user interface that allows users to upload catalogs of objects defined by celestial coordinates. AstroInspect automatically enriches these catalogs with complementary information, including imaging, spectroscopic, and photometric data retrieved in real time from surveys such as the Sloan Digital Sky Survey, the Legacy Surveys, and the Southern Photometric Local Universe Survey (S-PLUS). To demonstrate its scientific utility, we used AstroInspect to identify Hα emission-line galaxies within a 7 deg radius in the direction of the Hydra I cluster (also known as A1060) by visual inspection. Using a candidate set of 981 galaxies selected from S-PLUS photometric data, we produced a catalog of 80 galaxies with confirmed Hα emission. These results highlight the potential of AstroInspect to support efficient visual inspection workflows.

We present a sample of large double radio sources hosted by spiral galaxies (spiral double radio active galactic nuclei, SDRAGNs). Candidates were initially selected through the Radio Galaxy Zoo project and subsequently refined using Sloan Digital Sky Survey images. The most promising were targeted in the Zoo Gems Hubble Space Telescope (HST) program, yielding images for 36 candidates. We assess the likelihood that each spiral galaxy is the genuine host of the radio emission, finding 15 new high-probability SDRAGNs. The hosts are seen preferentially close to edge-on. SDRAGNs predominantly show type II Fanaroff–Riley (FR II) radio structures and optical pseudobulges. After accounting for sample selection effects, the radio-jet axes lie preferentially near the poles of the galactic disks; we find a constant probability distribution for intrinsic pole–jet angles ϕ < 30°, declining to zero at ϕ = 60°. We have obtained optical spectra for all these newly identified SDRAGNs. Among both previously known and new SDRAGN samples, 8/25 show Seyfert 2 signatures, 6/25 show central star formation, and 5/25 show low-ionization nuclear emission-line region emission strong enough to indicate active galactic nuclei (AGN) activity or shock ionization, broadly similar to radio galaxies in elliptical hosts but with the addition of star formation (diluting or masking weak AGN signatures). SDRAGNs include FR II sources seen at unusually low radio powers, and preferentially occur in significant galaxy overdensities on 1 Mpc scales. Our “false alarms”—systems where HST data show the spiral is not the actual host galaxy—include radio sources seen through large portions of foreground spiral disks, potentially providing useful probes for Faraday rotation studies of disk magnetic fields.

We present a ground-based time-series photometric study of stellar variability in four intermediate- to old-age open clusters—NGC 2192, NGC 2266, NGC 2509, and IC 1369—based on high-cadence Cousins R-band observations obtained with the 0.6 m VASISTHA telescope at the IERCOO observatory. The monitoring campaign comprises more than ∼34 hr of time-series data, providing sensitivity to short-period variability on timescales of ∼0.02–2 days. We identified between 190 and 290 probable members in each cluster using a Gaussian mixture model. Structural parameters were derived from radial density profiles fitted with King models. Fundamental parameters were further constrained using color–magnitude diagram analysis with PARSEC isochrones, yielding ages of ∼0.3–1.6 Gyr and distances of ∼2.5–3.9 kpc. From the time-series photometry, we identify four new variable stars and seven previously uncharacterized periodic variables, including δ Scuti and γ Doradus pulsators, as well as rotational variables. The detected variables exhibit periods between ∼0.12 and 0.90 days, with R-band amplitudes ranging from 0.01 to 0.20 mag. Periods were determined using Lomb–Scargle analysis of calibrated light curves. For a subset of variables, spectral energy distribution fitting was performed to derive effective temperatures (∼4300–10,000 K), radii (∼1.3–46 R_⊙), and luminosities (∼2–100 L_⊙), enabling reliable placement on the Hertzsprung–Russell diagram. We present PHOEBE light-curve modelling of the W UMa-type eclipsing binary Gaia DR3 2164531610149292288 in IC 1369, deriving its physical parameters and providing the first detailed characterization beyond its previously reported variability. These results demonstrate that combining dense-cadence ground-based observations with Gaia astrometry provides a reliable approach for identifying and characterizing variable stars in open clusters.

Recent observations have shown that sufficiently slow rotation disrupts the organization of large-scale magnetic field in older main-sequence stars, leading to weakened magnetic braking (WMB) and a collapse in the efficiency of the global stellar dynamo. Recent simulations predict a shift from solar-like to antisolar differential rotation (DR) at slower rotation rates, which typically do not occur on the main sequence due to WMB. However, physical expansion on the subgiant branch can eventually slow the stellar rotation beyond this threshold, yielding a noncycling large-scale field that revives magnetic braking. We combine asteroseismology from the Transiting Exoplanet Survey Satellite (TESS) with spectropolarimetry from the Large Binocular Telescope (LBT) to test these predictions in the old metal-rich subgiant 31 Aql. The LBT observations reveal a strong large-scale magnetic field in this star, and archival measurements of its chromospheric emission over 50 yr confirm that it is noncycling, as predicted. The star exhibits a variety of rotation periods during different observing seasons, consistent with DR but with no means of distinguishing between solar-like and antisolar patterns. We incorporate the TESS observations to estimate the current wind-braking torque of 31 Aql, demonstrating that it supports revived magnetic braking in this old subgiant. We also use rotational evolution modeling to place a preliminary constraint on the stellar Rossby number for the transition to antisolar DR. Future refinements in both asteroseismic observations and rotational modeling may yield improvements to this initial analysis.

We present the confirmation of HD 190360 d, a warm ($P=88.69{0}_{-0.049}^{+0.051}\,\mathrm{days}$), low-mass ($m\sin i=10.2{3}_{-0.80}^{+0.81}\,{M}_{\oplus }$) planet orbiting the nearby (d = 16.0 pc), Sun-like (G7) star HD 190360. We detect HD 190360 d at high statistical significance even though its radial velocity (RV) semiamplitude is only K = 1.48 ± 0.11 m s⁻¹. Such low-amplitude signals are often challenging to confirm due to potential confusion with low-amplitude stellar signals. The HD 190360 system previously had two known planets: the 1.7 M_J (true mass) HD 190360 b on a 7.9 yr orbit and the 21 M_⊕(minimum mass) HD 190360 c on a 17.1 days orbit. Here, we present an in-depth analysis of the HD 190360 planetary system that comprises more than 30 yr of RV measurements and absolute astrometry from the Hipparcos and Gaia spacecraft. Our analysis uses more than 1400 RVs, including nearly 100 from NEID. The proper motion anomaly as measured by these two astrometric missions solves for the dynamical mass of HD 190360 b and contributes to our understanding of the overall system architecture, while the long baseline of RVs enables the robust characterization of HD 190360 c and confirms the discovery of HD 190360 d.

The rapid growth of imaging and spectroscopic surveys has intensified the need for efficient tools that support visual inspection, a practice that remains essential for tasks such as classification, catalog refinement, and validation of automated methods. Existing solutions, however, often require the use of multiple platforms and complex workflows to integrate heterogeneous data. To address this challenge, we present the first release of AstroInspect (https://astroinspect.github.io), a web-based system designed to ensure seamless access to several astronomical resources. The system provides an intuitive graphical user interface that allows users to upload catalogs of objects defined by celestial coordinates. AstroInspect automatically enriches these catalogs with complementary information, including imaging, spectroscopic, and photometric data retrieved in real time from surveys such as the Sloan Digital Sky Survey, the Legacy Surveys, and the Southern Photometric Local Universe Survey (S-PLUS). To demonstrate its scientific utility, we used AstroInspect to identify Hα emission-line galaxies within a 7 deg radius in the direction of the Hydra I cluster (also known as A1060) by visual inspection. Using a candidate set of 981 galaxies selected from S-PLUS photometric data, we produced a catalog of 80 galaxies with confirmed Hα emission. These results highlight the potential of AstroInspect to support efficient visual inspection workflows.

We present a sample of large double radio sources hosted by spiral galaxies (spiral double radio active galactic nuclei, SDRAGNs). Candidates were initially selected through the Radio Galaxy Zoo project and subsequently refined using Sloan Digital Sky Survey images. The most promising were targeted in the Zoo Gems Hubble Space Telescope (HST) program, yielding images for 36 candidates. We assess the likelihood that each spiral galaxy is the genuine host of the radio emission, finding 15 new high-probability SDRAGNs. The hosts are seen preferentially close to edge-on. SDRAGNs predominantly show type II Fanaroff–Riley (FR II) radio structures and optical pseudobulges. After accounting for sample selection effects, the radio-jet axes lie preferentially near the poles of the galactic disks; we find a constant probability distribution for intrinsic pole–jet angles ϕ < 30°, declining to zero at ϕ = 60°. We have obtained optical spectra for all these newly identified SDRAGNs. Among both previously known and new SDRAGN samples, 8/25 show Seyfert 2 signatures, 6/25 show central star formation, and 5/25 show low-ionization nuclear emission-line region emission strong enough to indicate active galactic nuclei (AGN) activity or shock ionization, broadly similar to radio galaxies in elliptical hosts but with the addition of star formation (diluting or masking weak AGN signatures). SDRAGNs include FR II sources seen at unusually low radio powers, and preferentially occur in significant galaxy overdensities on 1 Mpc scales. Our “false alarms”—systems where HST data show the spiral is not the actual host galaxy—include radio sources seen through large portions of foreground spiral disks, potentially providing useful probes for Faraday rotation studies of disk magnetic fields.

We present a ground-based time-series photometric study of stellar variability in four intermediate- to old-age open clusters—NGC 2192, NGC 2266, NGC 2509, and IC 1369—based on high-cadence Cousins R-band observations obtained with the 0.6 m VASISTHA telescope at the IERCOO observatory. The monitoring campaign comprises more than ∼34 hr of time-series data, providing sensitivity to short-period variability on timescales of ∼0.02–2 days. We identified between 190 and 290 probable members in each cluster using a Gaussian mixture model. Structural parameters were derived from radial density profiles fitted with King models. Fundamental parameters were further constrained using color–magnitude diagram analysis with PARSEC isochrones, yielding ages of ∼0.3–1.6 Gyr and distances of ∼2.5–3.9 kpc. From the time-series photometry, we identify four new variable stars and seven previously uncharacterized periodic variables, including δ Scuti and γ Doradus pulsators, as well as rotational variables. The detected variables exhibit periods between ∼0.12 and 0.90 days, with R-band amplitudes ranging from 0.01 to 0.20 mag. Periods were determined using Lomb–Scargle analysis of calibrated light curves. For a subset of variables, spectral energy distribution fitting was performed to derive effective temperatures (∼4300–10,000 K), radii (∼1.3–46 R_⊙), and luminosities (∼2–100 L_⊙), enabling reliable placement on the Hertzsprung–Russell diagram. We present PHOEBE light-curve modelling of the W UMa-type eclipsing binary Gaia DR3 2164531610149292288 in IC 1369, deriving its physical parameters and providing the first detailed characterization beyond its previously reported variability. These results demonstrate that combining dense-cadence ground-based observations with Gaia astrometry provides a reliable approach for identifying and characterizing variable stars in open clusters.

Recent observations have shown that sufficiently slow rotation disrupts the organization of large-scale magnetic field in older main-sequence stars, leading to weakened magnetic braking (WMB) and a collapse in the efficiency of the global stellar dynamo. Recent simulations predict a shift from solar-like to antisolar differential rotation (DR) at slower rotation rates, which typically do not occur on the main sequence due to WMB. However, physical expansion on the subgiant branch can eventually slow the stellar rotation beyond this threshold, yielding a noncycling large-scale field that revives magnetic braking. We combine asteroseismology from the Transiting Exoplanet Survey Satellite (TESS) with spectropolarimetry from the Large Binocular Telescope (LBT) to test these predictions in the old metal-rich subgiant 31 Aql. The LBT observations reveal a strong large-scale magnetic field in this star, and archival measurements of its chromospheric emission over 50 yr confirm that it is noncycling, as predicted. The star exhibits a variety of rotation periods during different observing seasons, consistent with DR but with no means of distinguishing between solar-like and antisolar patterns. We incorporate the TESS observations to estimate the current wind-braking torque of 31 Aql, demonstrating that it supports revived magnetic braking in this old subgiant. We also use rotational evolution modeling to place a preliminary constraint on the stellar Rossby number for the transition to antisolar DR. Future refinements in both asteroseismic observations and rotational modeling may yield improvements to this initial analysis.

We present the confirmation of HD 190360 d, a warm ($P=88.69{0}_{-0.049}^{+0.051}\,\mathrm{days}$), low-mass ($m\sin i=10.2{3}_{-0.80}^{+0.81}\,{M}_{\oplus }$) planet orbiting the nearby (d = 16.0 pc), Sun-like (G7) star HD 190360. We detect HD 190360 d at high statistical significance even though its radial velocity (RV) semiamplitude is only K = 1.48 ± 0.11 m s⁻¹. Such low-amplitude signals are often challenging to confirm due to potential confusion with low-amplitude stellar signals. The HD 190360 system previously had two known planets: the 1.7 M_J (true mass) HD 190360 b on a 7.9 yr orbit and the 21 M_⊕(minimum mass) HD 190360 c on a 17.1 days orbit. Here, we present an in-depth analysis of the HD 190360 planetary system that comprises more than 30 yr of RV measurements and absolute astrometry from the Hipparcos and Gaia spacecraft. Our analysis uses more than 1400 RVs, including nearly 100 from NEID. The proper motion anomaly as measured by these two astrometric missions solves for the dynamical mass of HD 190360 b and contributes to our understanding of the overall system architecture, while the long baseline of RVs enables the robust characterization of HD 190360 c and confirms the discovery of HD 190360 d.

In 2021 May the Dark Energy Spectroscopic Instrument (DESI) collaboration began a 5 yr spectroscopic redshift survey to produce a detailed map of the evolving three-dimensional structure of the Universe between z = 0 and z ≈ 4. DESI’s principal scientific objectives are to place precise constraints on the equation of state of dark energy, the gravitationally driven growth of large-scale structure, and the sum of the neutrino masses, and to explore the observational signatures of primordial inflation. We present DESI DR1, which consists of all data acquired during the first 13 months of the DESI main survey, as well as a uniform reprocessing of the DESI Survey Validation data, which were previously made public in the DESI Early Data Release. The DR1 main survey includes high-confidence redshifts for 18.7M objects, of which 13.1M are spectroscopically classified as galaxies, 1.6M as quasars, and 4M as stars, making DR1 the largest sample of extragalactic redshifts ever assembled. We summarize the DR1 observations, the spectroscopic data-reduction pipeline and data products, large-scale structure catalogs, value-added catalogs, and describe how to access and interact with the data. In addition to fulfilling its core cosmological objectives with unprecedented precision, we expect DR1 to enable a wide range of transformational astrophysical studies and discoveries.

We present astrometric measurements for 13 cold brown dwarfs in the solar neighborhood (d  <  20 pc). By combining archival Spitzer data with our own Hubble Space Telescope (HST) observations, we achieve parallax uncertainties typically around 10%. Using Spitzer and HST photometry we compare our targets with other known late T and Y dwarfs in the Solar neighborhood, confirming that there is large intrinsic scatter in the near- and mid-infrared absolute magnitudes and colors of this population, further highlighting the diversity observed spectroscopically by several James Webb Space Telescope programs. This scatter makes photometric distance estimates highly unreliable and, therefore, makes astrometric parallax measurements fundamental for a meaningful characterization of even the nearest cold brown dwarfs.

Optical astronomical projects have traditionally relied on charge-coupled device (CCD) detectors. However, next-generation complementary metal-oxide-semiconductor (CMOS) technology, with advantages including high-speed readout, low dark current, and electronic shutter capability, is reshaping observational strategies and substantially improving observing efficiency. Many ground-based facilities are now transitioning from CCDs to scientific CMOS (sCMOS) detectors, yet the long-term radiation-induced performance degradation of sCMOS devices in space environments has not been systematically characterized. In this work, we irradiate a GSENSE1081BSI sCMOS detector under representative on-orbit operating conditions, including vacuum and low temperature, and continuously monitor its performance during both the irradiation and subsequent annealing phases. Based on the measured evolution of key detector parameters, we predict the corresponding on-orbit degradation of photometric signal-to-noise ratio. The predicted performance meets the requirements of the microlensing telescope of the forthcoming Earth 2.0 mission, demonstrating the suitability of this detector for space-based time-domain observations and for potential application in future space missions. Our results further provide quantitative benchmarks and practical guidance for ground-based radiation testing of sCMOS detectors and for assessing their long-term performance evolution in space.

Young stars host only a small fraction of the known exoplanet population because their photometric variability, magnetic activity, and frequent placement in dense, poorly resolved regions hamper exoplanet detections. Yet, measuring planets at these ages is crucial since these phases are when dynamical processes that drive planetary migration are most active. We assess the expected yield of a hypothetical Nancy Grace Roman Space Telescope transit survey of the Rosette Nebula, an ∼10 Myr star-forming region with a dense and diverse stellar population. Using the Roman Exposure Time Calculator to quantify sensitivity to Rosette members, we establish detection thresholds for companions and evaluate yields via Monte Carlo injection-recovery simulations, accounting for nebular extinction and youth-driven stellar variability. We predict the detection of 33 ± 9 young transiting exoplanets orbiting stellar hosts in a month-long survey, and 29 ± 8 in a 2 week survey. The extended baseline primarily improves sensitivity to longer-period planets orbiting FGK stars, while most M dwarf detections are well-sampled within 2 weeks. Irrespective of the temporal baseline, transit detections are dominated by 1–2 R_⊕ super-Earths and sub-Neptunes with P ≲ 8 days. Such a sample would substantially expand the census of only three detected transiting planets younger than 20 Myr around stars less massive than the Sun, probing an age regime in which planetary radii remain inflated, the stability of close-in orbits is uncertain, and planetary migration may still be ongoing. This survey offers a path to constrain early planetary evolution and establish prime follow-up targets for the James Webb Space Telescope, Rubin, and the Habitable Worlds Observatory.

The field of pulsar candidate identification still faces the challenge of algorithm generalization, as a single model often fails to adapt to datasets with diverse sources and characteristics. To address this issue, we propose a Genetic Algorithm for Multi-Modal Adaptive Convolutional Neural Network (GAMMA-CNN), which identifies pulsar candidates using diagnostic-style features derived from pulsar search pipelines. This model employs a genetic algorithm to automatically construct network architectures, introducing skip connections and multimodal fusion mechanisms. It can adaptively explore architectures under different modality configurations, thereby obtaining structures well suited to the current observational mode. GAMMA-CNN operates on diagnostic-style features and incorporates a flexible interface that automatically detects 1D and 2D plot formats, enabling convenient dimensional alignment and multimodal fusion. To evaluate the performance of GAMMA-CNN, we designed a series of experiments on the High Time Resolution Universe (HTRU) and Five-hundred-meter Aperture Spherical Telescope (FAST) datasets, covering both unimodal and multimodal inputs, including profile, dispersion measure curve (DM-curve), subband, subintegration, period–dispersion measure (HTRU only), and diagnostic plots. Results show that multimodal fusion enables the network to capture pulsar signal features more comprehensively and surpass the performance limits of unimodal models. When trained with multimodal data, comprising profile, DM-curve, subband, and subintegration plots, GAMMA-CNN achieved an F₁ score of 97.79%, recall of 95.80%, and precision of 99.80% on the HTRU dataset and an F₁ score of 99.70%, recall of 99.40%, and precision of 100.0% on the FAST dataset, demonstrating its performance across multiple modality settings on the HTRU and FAST datasets.

Multi-epoch radial velocity measurements of stars can be used to identify stellar, substellar, and planetary-mass companions. Even a small number of observation epochs can be informative about companions, though there can be multiple qualitatively different orbital solutions that fit the data. We have custom-built a Monte Carlo sampler (The Joker) that delivers reliable (and often highly multimodal) posterior samplings for companion orbital parameters given sparse radial velocity data. Here we use The Joker to perform a search for companions to 96,231 red giant stars observed in the APOGEE survey (DR14) with ≥3 spectroscopic epochs. We select stars with probable companions by making a cut on our posterior belief about the amplitude of the variation in stellar radial velocity induced by the orbit. We provide (1) a catalog of 320 companions for which the stellar companion’s properties can be confidently determined, (2) a catalog of 4898 stars that likely have companions, but would require more observations to uniquely determine the orbital properties, and (3) posterior samplings for the full orbital parameters for all stars in the parent sample. We show the characteristics of systems with confidently determined companion properties and highlight interesting systems with candidate compact object companions.

We present spectral and photometric observations of 10 Type Ia supernovae (SNe Ia) in the redshift range 0.16 ≤ z ≤ 0.62. The luminosity distances of these objects are determined by methods that employ relations between SN Ia luminosity and light curve shape. Combined with previous data from our High-z Supernova Search Team and recent results by Riess et al., this expanded set of 16 high-redshift supernovae and a set of 34 nearby supernovae are used to place constraints on the following cosmological parameters: the Hubble constant (H₀), the mass density (Ω_M), the cosmological constant (i.e., the vacuum energy density, Ω_Λ), the deceleration parameter (q₀), and the dynamical age of the universe (t₀). The distances of the high-redshift SNe Ia are, on average, 10%–15% farther than expected in a low mass density (Ω_M = 0.2) universe without a cosmological constant. Different light curve fitting methods, SN Ia subsamples, and prior constraints unanimously favor eternally expanding models with positive cosmological constant (i.e., Ω_Λ > 0) and a current acceleration of the expansion (i.e., q₀ < 0). With no prior constraint on mass density other than Ω_M ≥ 0, the spectroscopically confirmed SNe Ia are statistically consistent with q₀ < 0 at the 2.8 σ and 3.9 σ confidence levels, and with Ω_Λ > 0 at the 3.0 σ and 4.0 σ confidence levels, for two different fitting methods, respectively. Fixing a "minimal" mass density, Ω_M = 0.2, results in the weakest detection, Ω_Λ > 0 at the 3.0 σ confidence level from one of the two methods. For a flat universe prior (Ω_M + Ω_Λ = 1), the spectroscopically confirmed SNe Ia require Ω_Λ > 0 at 7 σ and 9 σ formal statistical significance for the two different fitting methods. A universe closed by ordinary matter (i.e., Ω_M = 1) is formally ruled out at the 7 σ to 8 σ confidence level for the two different fitting methods. We estimate the dynamical age of the universe to be 14.2 ± 1.7 Gyr including systematic uncertainties in the current Cepheid distance scale. We estimate the likely effect of several sources of systematic error, including progenitor and metallicity evolution, extinction, sample selection bias, local perturbations in the expansion rate, gravitational lensing, and sample contamination. Presently, none of these effects appear to reconcile the data with Ω_Λ = 0 and q₀ ≥ 0.

The all sky surveys done by the Palomar Observatory Schmidt, the European Southern Observatory Schmidt, and the United Kingdom Schmidt, the InfraRed Astronomical Satellite, and the Two Micron All Sky Survey have proven to be extremely useful tools for astronomy with value that lasts for decades. The Wide-field Infrared Survey Explorer (WISE) is mapping the whole sky following its launch on 2009 December 14. WISE began surveying the sky on 2010 January 14 and completed its first full coverage of the sky on July 17. The survey will continue to cover the sky a second time until the cryogen is exhausted (anticipated in 2010 November). WISE is achieving 5σ point source sensitivities better than 0.08, 0.11, 1, and 6 mJy in unconfused regions on the ecliptic in bands centered at wavelengths of 3.4, 4.6, 12, and 22 μm. Sensitivity improves toward the ecliptic poles due to denser coverage and lower zodiacal background. The angular resolution is 61, 64, 65, and 120 at 3.4, 4.6, 12, and 22 μm, and the astrometric precision for high signal-to-noise sources is better than 015.

The Sloan Digital Sky Survey (SDSS) will provide the data to support detailed investigations of the distribution of luminous and nonluminous matter in the universe: a photometrically and astrometrically calibrated digital imaging survey of π sr above about Galactic latitude 30° in five broad optical bands to a depth of g′ ∼ 23 mag, and a spectroscopic survey of the approximately 10⁶ brightest galaxies and 10⁵ brightest quasars found in the photometric object catalog produced by the imaging survey. This paper summarizes the observational parameters and data products of the SDSS and serves as an introduction to extensive technical on-line documentation.

Stellar distances constitute a foundational pillar of astrophysics. The publication of 1.47 billion stellar parallaxes from Gaia is a major contribution to this. Despite Gaia’s precision, the majority of these stars are so distant or faint that their fractional parallax uncertainties are large, thereby precluding a simple inversion of parallax to provide a distance. Here we take a probabilistic approach to estimating stellar distances that uses a prior constructed from a three-dimensional model of our Galaxy. This model includes interstellar extinction and Gaia’s variable magnitude limit. We infer two types of distance. The first, geometric, uses the parallax with a direction-dependent prior on distance. The second, photogeometric, additionally uses the color and apparent magnitude of a star, by exploiting the fact that stars of a given color have a restricted range of probable absolute magnitudes (plus extinction). Tests on simulated data and external validations show that the photogeometric estimates generally have higher accuracy and precision for stars with poor parallaxes. We provide a catalog of 1.47 billion geometric and 1.35 billion photogeometric distances together with asymmetric uncertainty measures. Our estimates are quantiles of a posterior probability distribution, so they transform invariably and can therefore also be used directly in the distance modulus ($5{\mathrm{log}}_{10}r\,-\,5$). The catalog may be downloaded or queried using ADQL at various sites (see http://www.mpia.de/~calj/gedr3_distances.html), where it can also be cross-matched with the Gaia catalog.

The light scattered from dust grains in debris disks is typically modeled as compact spheres using the Lorenz–Mie theory or as porous spheres by incorporating an effective medium theory. In this work we examine the effect of incorporating a more realistic particle morphology on estimated radiation-pressure blowout sizes. To calculate the scattering and absorption cross-sections of irregularly shaped dust grains, we use the discrete dipole approximation. These cross-sections are necessary to calculate the β-ratio, which determines whether dust grains can remain gravitationally bound to their star. We calculate blowout sizes for a range of stellar spectral types corresponding with stars known to host debris disks. As with compact spheres, more luminous stars blow out larger irregularly shaped dust grains. We also find that dust grain composition influences blowout size such that absorptive grains are more readily removed from the disk. Moreover, the difference between blowout sizes calculated assuming spherical particles versus particle morphologies more representative of real dust particles is compositionally dependent as well, with blowout size estimates diverging further for transparent grains. We find that the blowout sizes calculated have a strong dependence on the particle model used, with differences in the blowout size calculated being as large as an order of magnitude for particles of similar porosities.

We have compiled a new and complete catalog of the main properties of the 1509 pulsars for which published information currently exists. The catalog includes all spin-powered pulsars, as well as anomalous X-ray pulsars and soft gamma-ray repeaters showing coherent pulsed emission, but excludes accretion-powered systems. References are given for all data listed. We have also developed a new World Wide Web interface for accessing and displaying either tabular or plotted data with the option of selecting pulsars to be displayed via logical conditions on parameter expressions. The Web interface has an "expert" mode giving access to a wider range of parameters and allowing the use of custom databases. For users with locally installed software and database on Unix or Linux systems, the catalog may be accessed from a command-line interface. C-language functions to access specified parameters are also available. The catalog is updated from time to time to include new information.

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the Sloan 2.5 m Telescope, APOGEE has collected a half million high-resolution (R ∼ 22,500), high signal-to-noise ratio (>100), infrared (1.51–1.70 μm) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design—hardware, field placement, target selection, operations—and gives an overview of these aspects as well as the data reduction, analysis, and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity, and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12 and later releases, all of the APOGEE data products are publicly available.

Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998% of the celestial sphere in the near-infrared J (1.25 μm), H (1.65 μm), and K_s (2.16 μm) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 σ point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and K_s bands, respectively, for virtually the entire sky. Bright source extractions have 1 σ photometric uncertainty of <0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are <0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.

The Dark Energy Spectroscopic Instrument (DESI) completed its 5 month Survey Validation in 2021 May. Spectra of stellar and extragalactic targets from Survey Validation constitute the first major data sample from the DESI survey. This paper describes the public release of those spectra, the catalogs of derived properties, and the intermediate data products. In total, the public release includes good-quality spectral information from 466,447 objects targeted as part of the Milky Way Survey, 428,758 as part of the Bright Galaxy Survey, 227,318 as part of the Luminous Red Galaxy sample, 437,664 as part of the Emission Line Galaxy sample, and 76,079 as part of the Quasar sample. In addition, the release includes spectral information from 137,148 objects that expand the scope beyond the primary samples as part of a series of secondary programs. Here, we describe the spectral data, data quality, data products, Large-Scale Structure science catalogs, access to the data, and references that provide relevant background to using these spectra.