adsabs/SciX_UAT_keywords huggingface dataset:
The Gaia-Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age

Studies of exoplanet demographics require large samples and precise constraints on exoplanet host stars. Using the homogeneous Kepler stellar properties derived using the Gaia Data Release 2 by Berger et al., we recompute Kepler planet radii and incident fluxes and investigate their distributions with stellar mass and age. We measure the stellar mass dependence of the planet radius valley to be $d\mathrm{log}{R}_{{\rm{p}}}$ / $d\mathrm{log}{M}_{\star }$ = ${0.26}_{-0.16}^{+0.21}$ , consistent with the slope predicted by a planet mass dependence on stellar mass (0.24-0.35) and core-powered mass loss (0.33). We also find the first evidence of a stellar age dependence of the planet populations straddling the radius valley. Specifically, we determine that the fraction of super-Earths (1-1.8 ${R}_{\oplus }$ ) to sub-Neptunes (1.8-3.5 ${R}_{\oplus }$ ) increases from 0.61 ± 0.09 at young ages (<1 Gyr) to 1.00 ± 0.10 at old ages (>1 Gyr), consistent with the prediction by core-powered mass loss that the mechanism shaping the radius valley operates over Gyr timescales. Additionally, we find a tentative decrease in the radii of relatively cool (Fp < 150 ${F}_{\oplus }$ ) sub-Neptunes over Gyr timescales, which suggests that these planets may possess H/He envelopes instead of higher mean molecular weight atmospheres. We confirm the existence of planets within the hot sub-Neptunian "desert" (2.2 R⊕ < Rp < 3.8 ${R}_{\oplus }$ , Fp > 650 ${F}_{\oplus }$ ) and show that these planets are preferentially orbiting more evolved stars compared to other planets at similar incident fluxes. In addition, we identify candidates for cool (Fp < 20 ${F}_{\oplus }$ ) inflated Jupiters, present a revised list of habitable zone candidates, and find that the ages of single and multiple transiting planet systems are statistically indistinguishable.

Keywords: super earths; habitable planets; exoplanet catalogs; planet hosting stars; exoplanet systems; exoplanet evolution; hot neptunes; extrasolar gaseous giant planets
Energy Dependence of the Low-frequency Quasiperiodic Oscillations in Swift J1727.8–1613

Based on observations from the Insight Hard X-ray Modulation Telescope (Insight-HXMT), an analysis of type C quasiperiodic oscillations (QPOs) observed during the outburst of the new black hole candidate Swift J1727.8–1613 in 2023 was conducted. This analysis scrutinized the QPO's evolution throughout the outburst, particularly noting its rapid frequency escalation during two flare events. Utilizing the energy range covered by Insight-HXMT, a dependency of the QPO frequency on energy was observed. Below approximately 3 Hz, minimal variations in frequency with energy were noted, whereas clear variations with photon energy were observed when it exceeded approximately 3 Hz. Additionally, a sharp drop in the rate of change was observed when the frequency exceeded approximately 8 Hz. This behavior, similar to several previously reported sources, suggests the presence of a common underlying physical mechanism. Moreover, the QPO rms–frequency relationship can be explained by the Lense–Thirring precession model. The relationship between rms energy and phase lag with frequency suggests the black hole system as a high-inclination source.

Keywords: black hole physics; high energy astrophysics; stellar accretion disks; x-ray sources; x-ray binary stars
Probing the Growth of Massive Black Holes with Black Hole-Host Galaxy Spin Correlations

Supermassive black holes are commonly found at the centers of their host galaxies, but their formation still remains an open question. In light of the tight correlation between the black hole (BH) mass and the velocity dispersions of the bulge component of the host galaxy, a BH-host galaxy coevolution scenario has been established. Such a description, however, still contains many theoretical uncertainties, including puzzles about the formation of BH seeds at high redshifts and the growth channel fueling these seeds. In this work, we systematically analyze the signatures of different growth channels on massive BH (MBH) spins. We show that different growth channels can be partially distinguished with the magnitudes of MBH spins inferred from extreme-mass-ratio inspirals detected by the Laser Interferometer Space Antenna. In addition, we propose measuring the correlation between the directions of MBH spins and their host galaxy spins, which is possible for extreme-mass-ratio inspirals happening in low-redshift galaxies ( $z\leqslant 0.3$ ). With the inclusion of spin direction correlation different formation channels shall be significantly better constrained.

Keywords: supermassive black holes; galaxy mergers; gravitational wave sources; gravitational waves
Cosmic Ray Jump Detection for the Roman Wide Field Instrument

We investigate algorithms for detecting and correcting for jumps due to cosmic rays in infrared detectors, with emphasis on Roman telescope's Wide Field Instrument. We use a statistic S based on the excess difference between adjacent resultants (average over a group of reads) normalized to the square root of the expected variance that accommodates the uneven resultants of Roman. We show that it is important to account for the covariance of excess difference with that of the estimated count rate. Due to averaging of reads, the ability to detect jumps is reduced, specially if the jump is in the first or the last resultant. Having the first and last resultants as a single-read resultants improves the ability to detect cosmic rays. The signal due to a jump is split across two resultant differences and this motivates small adjustments to the basic algorithm which improves the jump detection. Bias and false negative rate are investigated using Monte Carlo simulations for a few readout patterns. In order to investigate other scenarios approximate formulas for predicting the bias and the misclassification rate are presented. Using cosmic ray properties based on JWST darks, we show that for high count rates (1000 e‑1 s‑1) most of the cosmic rays remain undetected, with 65% missed identifications. When averaging over multiple exposures, due to low event rates of cosmic rays, the overall bias in estimated count rate due to undetected cosmic rays is negligible. However, for a single exposure with an undetected cosmic ray, one can have a bias of a few percent. This will manifest as abrupt changes in brightness of targets. Fortunately, the bias ranges between 1 and 5 the measurement uncertainty, and this fact can be used to screen out cosmic rays for scientific applications that seek to detect short duration time domain events.

Keywords: space telescopes; near infrared astronomy; algorithms; cosmic rays; astronomy data analysis
Nearby Quintuple Systems κ Tucanae and ξ Scorpii

Architecture and parameters of two wide, nearby hierarchical systems containing five solar-type stars each, κ Tuc and ξ Sco, are studied. Using Gaia astrometry and photometry, masses are determined from visual orbits and isochrones, and effective temperatures from spectra or colors. Both systems are ∼2 Gyr old. Their spatial motion corresponds to a young disk but does not match any known kinematic group. Internal proper motions relative to the center of mass and radial velocities show that wide ∼8 kau outer pairs are bound. No correlation between orbit orientations in the inner subsystems is observed. All masses except one are confined to the narrow range from 0.8 to 1.5 solar. Strongly correlated masses and wide orbits can be explained if those systems formed by fragmentation in relative isolation and their components accreted gas from a common source, as expected in a hierarchical collapse. Young moving groups could be formed in similar environments, and many of them contain high-order hierarchies.

Keywords: visual binary stars; wide binary stars; multiple stars; star formation
Chemical Composition of Bright Stars in the Northern Hemisphere: Star-Planet Connection

In fulfilling the aims of the planetary and asteroseismic research missions, such as that of the NASA Transiting Exoplanet Survey Satellite (TESS) space telescope, accurate stellar atmospheric parameters and a detailed chemical composition are required as inputs. We have observed high-resolution spectra for all 848 bright (V < 8 mag) stars that are cooler than F5 spectral class in the area up to 12 deg surrounding the northern TESS continuous viewing zone and uniformly determined the main atmospheric parameters, ages, orbital parameters, velocity components, and precise abundances of up to 24 chemical species (C(C2), N(CN), [O I], Na I, Mg I, Al I, Si I, Si II, Ca I, Ca II, Sc I, Sc II, Ti I, Ti II, V I, Cr I, Cr II, Mn I, Fe I, Fe II, Co I, Ni I, Cu I, and Zn I) for 740 slowly rotating stars. The analysis of 25 planet-hosting stars in our sample drove us to the following conclusions: the dwarf stars hosting high-mass planets are more metal rich than those with low-mass planets. We find slightly negative C/O and Mg/Si slopes toward the stars with high-mass planets. All the low-mass planet hosts in our sample show positive Δ[El/Fe] versus condensation temperature slopes, in particular, the star with the largest number of various planets. The high-mass planet hosts have a diversity of slopes, but in more metal-rich, older, and cooler stars, the positive elemental abundance slopes are more common.

Keywords: high resolution spectroscopy
A Comparison between the Morphologies and Structures of Dwarf Galaxies with and without Active Massive Black Holes

We study the morphologies and structures of 57 dwarf galaxies that are representative of the general population of dwarf galaxies and compare their demographics to a sample of dwarf galaxies hosting optically selected active galactic nuclei (AGNs). The two samples span the same galaxy stellar mass (109 ≲ M ⋆/M ⊙ ≲ 109.5) and color range, and the observations are well-matched in physical resolution. The fractions of irregular galaxies (14%) and early types/ellipticals (~18%) are nearly identical among the two samples. However, among galaxies with disks (the majority of each sample), the AGN hosts almost always have a detectable (pseudo)bulge, while a large fraction of the non-AGN hosts are pure disk galaxies with no detectable (pseudo)bulge. Central point sources of light consistent with nuclear star clusters are detected in many of the non-AGN hosts. In contrast, central point sources detected in the AGN hosts are, on average, more than 2 orders of magnitude more luminous, suggesting the point sources in these objects are dominated by AGN light. The preference for (pseudo)bulges in dwarf AGN hosts may inform searches for massive black holes in dwarf galaxies and attempts to constrain the black hole occupation fraction, which, in turn, has implications for our understanding of black hole seeding mechanisms.

Keywords: dwarf galaxies; active galactic nuclei; intermediate-mass black holes; agn host galaxies
Large-scale Linear Magnetic Holes with Magnetic Mirror Properties in Hybrid Simulations of Solar Wind Turbulence

Magnetic holes (MHs) are coherent magnetic field dips whose size ranges from fluid to kinetic scale, ubiquitously observed in the heliosphere and in planetary environments. Despite the long-standing effort in interpreting the abundance of observations, the origin and properties of MHs are still debated. In this Letter, we investigate the interplay between plasma turbulence and MHs, using a 2D hybrid simulation initialized with solar wind parameters. We show that fully developed turbulence exhibits localized elongated magnetic depressions, whose properties are consistent with linear MHs frequently encountered in space. The observed MHs develop self-consistently from the initial magnetic field perturbations by trapping hot ions with large pitch angles. Ion trapping produces an enhanced perpendicular temperature anisotropy that makes MHs stable for hundreds of ion gyroperiods, despite the surrounding turbulence. We introduce a new quantity, based on local magnetic field and ion temperature values, to measure the efficiency of ion trapping, with potential applications to the detection of MHs in satellite measurements. We complement this method by analyzing the ion velocity distribution functions inside MHs. Our diagnostics reveal the presence of trapped gyrotropic ion populations, whose velocity distribution is consistent with a loss cone, as expected for the motion of particles inside a magnetic mirror. Our results have potential implications for the theoretical and numerical modeling of MHs.

Keywords: solar wind
Analysis of the Internal Structure of the Streamer Blowout Observed by the Parker Solar Probe During the First Solar Encounter

In this paper, we present an analysis of the internal structure of a coronal mass ejection (CME) detected by in situ instruments on board the Parker Solar Probe (PSP) spacecraft during its first solar encounter. On 2018 November 11 at 23:53 UT, the FIELDS magnetometer measured an increase in strength of the magnetic field as well as a coherent change in the field direction. The SWEAP instrument simultaneously detected a low proton temperature and signatures of bidirectionality in the electron pitch angle distribution (PAD). These signatures are indicative of a CME embedded in the slow solar wind. Operating in conjunction with PSP was the STEREO A spacecraft, which enabled the remote observation of a streamer blowout by the SECCHI suite of instruments. The source at the Sun of the slow and well-structured flux rope was identified in an overlying streamer, the details of which are described in Korreck et al. Our detailed inspection of the internal transient structure magnetic properties suggests high complexity in deviations from an ideal flux rope 3D topology. Reconstructions of the magnetic field configuration reveal a highly distorted structure consistent with the highly elongated "bubble" observed remotely. A double-ring substructure observed in the SECCHI-COR2 field of view (FOV) is suggestive of a double internal flux rope. Furthermore, we describe a scenario in which mixed topology of a closed flux rope is combined with the magnetically open structure, which helps explain the flux dropout observed in the measurements of the electron PAD. Our justification for this is the plethora of structures observed by the EUV imager (SECCHI-EUVI) in the hours preceding the streamer blowout evacuation. Finally, taking advantage of the unique observations from PSP, we explore the first stages of the effects of coupling with the solar wind and the evolutionary processes in the magnetic structure. We found evidence of bifurcated current sheets in the structure boundaries, suggestive of magnetic reconnection. Our analysis of the internal force imbalance indicates that internal Lorentz forces continue to dominate the evolution of the structure in the COR2 FOV and serve as the main driver of the internal flux rope distortion detected in situ at PSP solar distance.

Keywords: solar coronal mass ejections; solar wind; interplanetary magnetic fields; space plasmas; solar magnetic reconnection
Disks around Young Planetary-mass Objects: Ultradeep Spitzer Imaging of NGC 1333

We report on a sensitive infrared search for disks around isolated young planetary-mass objects (PMOs) in the NGC 1333 cluster, by stacking 70 Spitzer/IRAC frames at 3.6 and 4.5 μm. Our coadded images go >2.3 mag deeper than single-epoch frames, and cover 50 brown dwarfs, 15 of which have M9 or later spectral types. Spectral types >M9 correspond to masses in the giant-planet domain, i.e., near or below the deuterium-burning limit of 0.015 M ⊙. Five of the 12 PMOs show definitive evidence of excess, implying a disk fraction of 42%, albeit with a large statistical uncertainty given the small sample. Comparing with measurements for higher-mass objects, the disk fraction does not decline substantially with decreasing mass in the substellar domain, consistent with previous findings. Thus, free-floating PMOs have the potential to form their own miniature planetary systems. We note that only one of the six lowest-mass objects in NGC 1333, with spectral type L0 or later, has a confirmed disk. Reviewing the literature, we find that the lowest-mass free-floating objects with firm disk detections have masses ~0.01 M ⊙ (or ~10 M Jup). It is not clear yet whether even lower-mass objects harbor disks. If not, it may indicate that ~10 M Jup is the lower-mass limit for objects that form like stars. Our disk-detection experiment on deep Spitzer images paves the way for studies with JWST at longer wavelengths and higher sensitivity, which will further explore disk prevalence and formation of free-floating PMOs.

Keywords: brown dwarfs
X-Ray Observations of the Enigmatic Wolf–Rayet System θ Mus: Two's Company but Three's a Crowd

θ Mus is a remarkable spectroscopic binary (SB) consisting of a carbon-type Wolf–Rayet star and OV companion (WC6+O6–7V) in a ≈19 days orbit. In addition an O-supergiant is visually detected at a small offset of 46 mas and if gravitationally bound to the SB system would have an orbital period of many decades. θ Mus is X-ray bright and a nonthermal radio source as commonly observed in massive colliding wind (CW) binaries. We present new Chandra X-ray observations of θ Mus, which complement previous XMM-Newton observations. The X-ray emission consists of a cool, nearly steady, weakly absorbed plasma component with broad redshifted emission lines located in an extended region far from the SB system. Hotter plasma is also present traced by Fe XXV emission. The observed flux in the ≈2–5 keV range dropped significantly on a timescale of ≤5 yr. The flux decrease can be attributed to an increase in absorption toward the hotter plasma which is likely located in the confined wind interaction region of the short-period SB system. The X-ray emission of θ Mus is remarkably similar to the WC+O binary γ 2 Vel including carbon recombination spectral lines but both systems show unusual line centroid properties that challenge CW models.

Keywords: wolf-rayet stars; x-ray astronomy; spectroscopic binary stars
The Dark World: A Tale of WASP-43b in Reflected Light with HST WFC3/UVIS

Optical reflected light eclipse observations provide a direct probe of exoplanet scattering properties, such as from aerosols. We present here the photometric reflected light observations of WASP-43b using the Hubble Space Telescope (HST) WFC3/UVIS instrument with the F350LP filter (346-822 nm) encompassing the entire optical band. This is the first reflected light photometric eclipse using UVIS in scanning mode; as such, we further detail our scanning extraction and analysis pipeline Arctor. Our HST WFC3/UVIS eclipse light curve for WASP-43b derived a 3σ upper limit of 67 ppm on the eclipse depth, which implies that WASP-43b has a very dark dayside atmosphere. With our atmospheric modeling campaign, we compared our reflected light constraints with predictions from global circulation and cloud models benchmarked with HST and Spitzer observations of WASP-43b. We infer that we do not detect clouds on the dayside within the pressure levels probed by HST WFC3/UVIS with the F350LP filter (P > 1 bar). This is consistent with the general circulation model predictions based on previous WASP-43b observations. Dayside emission spectroscopy results from WASP-43b with HST and Spitzer observations are likely to not be significantly affected by contributions from cloud particles.

Keywords: exoplanet atmospheric composition; exoplanet atmospheres; exoplanet astronomy; exoplanets; atmospheric composition; atmospheric science; planetary atmospheres
Gravitational-wave Signatures from Compact Object Binaries in the Galactic Center

Almost every galaxy has a supermassive black hole (SMBH) residing at its center, the Milky Way included. Recent studies suggest that these unique places are expected to host a high abundance of stellar and compact object binaries. These binaries form hierarchical triple systems with the SMBH and undergo the eccentric Kozai-Lidov (EKL) mechanism. Here we estimate the detectability of potential gravitational-wave emission from these compact objects within the frequency band of the Laser Interferometer Space Antenna (LISA) and Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo detectors. We generate a post-EKL population of stars at the onset of Roche limit crossing and follow their evolution to compact object binaries. As a proof of concept, we adopt two metallicities, solar metallicity (Z = 0.02) and 15% of it (Z = 0.003). We demonstrate that over the observation timescale of LISA, black hole (BH) binaries (BH-BH) and white dwarf (WD) binaries provide the most prominent GW sources via the EKL-assisted merger channel. Systems involving neutron stars (NSs) are less observable but possibly abundant through different merger channels. Our population synthesis of BH-BH with Z = 0.02 (Z = 0.003) translates to ~4 (24) events per year with LIGO within a 1 Gpc3 sphere. We also estimated the number of binaries visible in the LISA band within the inner parsec of our Galactic center (and possibly other galaxies) to be about 14-150 WD-WD, 0-2 NS-BH, 0.2-4 NS-NS, and 0.3-20 BH-BH.

Keywords: gravitational wave detectors; galactic center; white dwarf stars; neutron stars; binary stars; compact binary stars; gravitational waves
Depletion of Moderately Volatile Elements by Open-system Loss in the Early Solar Nebula

Rocky bodies of the inner solar system display a systematic depletion of "moderately volatile elements" (MVEs) that correlates with the expected condensation temperature of their likely host materials under protoplanetary nebula conditions. In this paper, we present and test a new hypothesis in which open-system loss processes irreversibly remove vaporized MVEs from high nebula altitudes, leaving behind the more refractory solids residing much closer to the midplane. The MVEs irreversibly lost from the nebula through these open-system loss processes are then simply unavailable for condensation onto planetesimals forming even much later, after the nebula has cooled, overcoming a critical difficulty encountered by previous models of this type. We model open-system loss processes operating at high nebula altitudes, such as resulting from disk winds flowing out of the system entirely, or layered accretion directly onto the young Sun. We find that mass-loss rates higher than those found in typical T-Tauri disk winds, lasting short periods of time, are most satisfactory, pointing to multiple intense early outburst stages. Using our global nebula model, incorporating realistic particle growth and inward drift for solids, we constrain how much the MVE-depletion signature in the inner region is diluted by the drift of undepleted material from the outer nebula. We also find that a significant irreversible loss of the common rock-forming elements (Fe, Mg, Si) can occur, leading to a new explanation of another long-standing puzzle of the apparent "enhancement" in the relative abundance of highly refractory elements in chondrites.

Keywords: meteorites; planetesimals; chondrites; meteorite composition; solar system formation