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111. 181 new planet candidates with TESS
ID:
ivo://CDS.VizieR/J/AJ/161/273
Title:
181 new planet candidates with TESS
Short Name:
J/AJ/161/273
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Transiting Exoplanet Survey Satellite (TESS) mission measured light from stars in ~75% of the sky throughout its 2yr primary mission, resulting in millions of TESS 30-minute-cadence light curves to analyze in the search for transiting exoplanets. To search this vast data trove for transit signals, we aim to provide an approach that both is computationally efficient and produces highly performant predictions. This approach minimizes the required human search effort. We present a convolutional neural network, which we train to identify planetary transit signals and dismiss false positives. To make a prediction for a given light curve, our network requires no prior transit parameters identified using other methods. Our network performs inference on a TESS 30-minute-cadence light curve in ~5ms on a single GPU, enabling large-scale archival searches. We present 181 new planet candidates identified by our network, which pass subsequent human vetting designed to rule out false positives. Our neural network model is additionally provided as open-source code for public use and extension.
112. New reduction of UVES data for 35 M dwarfs
ID:
ivo://CDS.VizieR/J/AJ/158/251
Title:
New reduction of UVES data for 35 M dwarfs
Short Name:
J/AJ/158/251
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UVES (Ultraviolet and Visible Spectrometer) M Dwarf Planet Search program surveyed 40 M dwarfs and 1 M giant from 2000 through 2007 March. Two of the M dwarfs were double-lined spectroscopic binaries. The 38 single-lined M dwarfs in this survey are among the nearest and brightest M dwarfs. Starting with the reduced 1D spectra provided by the UVES team, we reanalyzed the UVES velocities of Proxima Cen as part of the "Pale Red Dot" program. The velocity rms decreased from 3.6 to 2.3 m/s. Motivated by this result, we have harvested all of the raw data from the UVES M Dwarf Planet Search from the European Southern Observatory (ESO) archives and have written custom packages to generate 1D spectra from the raw data, and velocities from the 1D spectra. The median improvement in the velocity rms from the new analysis is 1.8 m/s. Six of the 38 M dwarfs from the original study had a velocity rms<4 m/s. In the reanalysis presented here, 22 of these stars have a velocity rms<4 m/s. We improve the upper limits on possible planets orbiting these stars by a factor of typically two to three. For many of these M dwarfs, these observations represent the first epoch of high-precision velocity measurements.
113. New substellar discoveries from Kepler and K2
ID:
ivo://CDS.VizieR/J/AJ/158/38
Title:
New substellar discoveries from Kepler and K2
Short Name:
J/AJ/158/38
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discoveries of a brown dwarf (BD) and a low-mass star from the Kepler and K2 missions. The newly discovered BD is EPIC 212036875b and the low-mass star is KOI-607b. EPIC 212036875b has a mass of M_b_=52.3+/-1.9 M_J_, a radius of R_b_=0.874+/-0.017 R_J_, and orbits its host star in P=5.169885+/-0.000027 days. Its host star is a late F-type star with M_*_=1.288+/-0.065 M_{sun}_, R_*_= 1.498+/-0.025 R_{sun}_, and T_eff_=6238+/-60 K. KOI-607b has a mass of M_b_=95.1+/-3.4 M_J_, a radius of R_b_=1.089+/-0.089 R_J_, and an orbital period of P=5.89399148+/-0.00000060 days. The primary star in the KOI-607 system is a G dwarf with M_*_=0.993+/-0.052 M_{sun}_, R_*_= 0.915+/-0.031 R_{sun}_, and T_eff_=5418+/-87 K. We also revisit a BD, CWW 89Ab, that was previously published by Nowak et al. 2017AJ....153..131N (under the designation EPIC 219388192b). CWW 89Ab is one of two known transiting BDs associated with a star cluster, which illustrates the need for more BDs with accurate masses, radii, and reliable age determinations to test theoretical models. We find that the newly discovered BD, EPIC 212036875b, falls in the middle of the so-called BD desert, indicating that EPIC 212036875b is either a particularly rare object, or the BD desert may not be so dry after all.
114. NIR transmission spectra of TRAPPIST-1 planets
ID:
ivo://CDS.VizieR/J/AJ/156/178
Title:
NIR transmission spectra of TRAPPIST-1 planets
Short Name:
J/AJ/156/178
Date:
21 Oct 2021
Publisher:
CDS
Description:
The seven approximately Earth-sized transiting planets in the TRAPPIST-1 system provide a unique opportunity to explore habitable- and nonhabitable-zone small planets within the same system. Its habitable-zone exoplanets - due to their favorable transit depths - are also worlds for which atmospheric transmission spectroscopy is within reach with the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST). We present here an independent reduction and analysis of two HST Wide Field Camera 3 (WFC3) near-infrared transit spectroscopy data sets for six planets (b through g). Utilizing our physically motivated detector charge-trap correction and a custom cosmic-ray correction routine, we confirm the general shape of the transmission spectra presented by de Wit et al. (2016Natur.537...69D). Our data reduction approach leads to a 25% increase in the usable data and reduces the risk of confusing astrophysical brightness variations (e.g., flares) with instrumental systematics. No prominent absorption features are detected in any individual planet's transmission spectra; by contrast, the combined spectrum of the planets shows a suggestive decrease around 1.4 {mu}m similar to an inverted water absorption feature. Including transit depths from K2, the SPECULOOS-South Observatory, and Spitzer, we find that the complete transmission spectrum is fully consistent with stellar contamination owing to the transit light source effect. These spectra demonstrate how stellar contamination can overwhelm planetary absorption features in low-resolution exoplanet transit spectra obtained by HST and JWST and also highlight the challenges in combining multi-epoch observations for planets around rapidly rotating spotted stars.
115. NUV and FUV measurements of planet host stars
ID:
ivo://CDS.VizieR/J/ApJ/890/23
Title:
NUV and FUV measurements of planet host stars
Short Name:
J/ApJ/890/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We search for evidence of the cause of the exoplanet radius gap, i.e., the dearth of planets with radii near 1.8R_{Earth}_. If the cause were photoevaporation, the radius gap should trend with proxies for the early-life high-energy emission of the planet-hosting stars. If, alternatively, the cause were core-powered mass loss, no such trends should exist. Critically, spurious trends between the radius gap and stellar properties arise from an underlying correlation with instellation. After accounting for this underlying correlation, we find that no trends remain between the radius gap and stellar mass or present-day stellar activity as measured by near-UV emission. We dismiss the nondetection of a radius gap trend with near-UV emission because present-day near-UV emission is unlikely to trace early-life high-energy emission, but we provide a catalog of Galaxy Evolution Explorer near-UV and far-UV emission measurements for general use. We interpret the nondetection of a radius gap trend with stellar mass by simulating photoevaporation with mass-dependent evolution of stellar high-energy emission. The simulation produces an undetectable trend between the radius gap and stellar mass under realistic sources of error. We conclude that no evidence, from this analysis or others in the literature, currently exists that clearly favors either photoevaporation or core-powered mass loss as the primary cause of the exoplanet radius gap. However, repeating this analysis once the body of well-characterized <4R_{Earth}_ planets has roughly doubled could confirm or rule out photoevaporation.
116. Obliquities of planetary & eclipsing binary systems
ID:
ivo://CDS.VizieR/J/AJ/155/177
Title:
Obliquities of planetary & eclipsing binary systems
Short Name:
J/AJ/155/177
Date:
21 Oct 2021
Publisher:
CDS
Description:
The light curve of an eclipsing system shows anomalies whenever the eclipsing body passes in front of active regions on the eclipsed star. In some cases, the pattern of anomalies can be used to determine the obliquity {Psi} of the eclipsed star. Here we present a method for detecting and analyzing these patterns, based on a statistical test for correlations between the anomalies observed in a sequence of eclipses. Compared to previous methods, ours makes fewer assumptions and is easier to automate. We apply it to a sample of 64 stars with transiting planets and 24 eclipsing binaries for which precise space-based data are available, and for which there was either some indication of flux anomalies or a previously reported obliquity measurement. We were able to determine obliquities for 10 stars with hot Jupiters. In particular we found {Psi}~<10{deg} for Kepler-45, which is only the second M dwarf with a measured obliquity. The other eight cases are G and K stars with low obliquities. Among the eclipsing binaries, we were able to determine obliquities in eight cases, all of which are consistent with zero. Our results also reveal some common patterns of stellar activity for magnetically active G and K stars, including persistently active longitudes.
117. Observation & radial velocity of WASP-150 & WASP-176
ID:
ivo://CDS.VizieR/J/AJ/159/255
Title:
Observation & radial velocity of WASP-150 & WASP-176
Short Name:
J/AJ/159/255
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of two transiting exoplanets from the Wide Angle Search for Planets (WASP) survey, WASP-150b and WASP-176b. WASP-150b is an eccentric (e=0.38) hot Jupiter on a 5.6day orbit around a V=12.03, F8 main-sequence host. The host star has a mass and radius of 1.4M_{sun}_ and 1.7R_{sun}_ respectively. WASP-150b has a mass and radius of 8.5M_J_ and 1.1R_J_, leading to a large planetary bulk density of 6.4{rho}_J_. WASP-150b is found to be ~3Gyr old, well below its circularization timescale, supporting the eccentric nature of the planet. WASP-176b is a hot Jupiter planet on a 3.9day orbit around a V=12.01, F9 sub-giant host. The host star has a mass and radius of 1.3M{sun} and 1.9R{sun}. WASP-176b has a mass and radius of 0.86M_J_ and 1.5R_J_, respectively, leading to a planetary bulk density of 0.23{rho}_J_.
118. Observations of the Kepler field with TESS
ID:
ivo://CDS.VizieR/J/AJ/157/235
Title:
Observations of the Kepler field with TESS
Short Name:
J/AJ/157/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examine the ability of the Transiting Exoplanet Survey Satellite (TESS) to detect and improve our understanding of planetary systems in the Kepler field. By modeling the expected transits of all confirmed and candidate planets detected by Kepler as expected to be observed by TESS, we provide a probabilistic forecast of the detection of each Kepler planet in TESS data. We find that TESS has a greater than 50% chance of detecting 260 of these planets at the 3{sigma} level in one sector of observations and an additional 120 planets in two sectors. Most of these are large planets in short orbits around their host stars, although a small number of rocky planets are expected to be recovered. Most of these systems have only one known transiting planet; in only ~5% of known multiply transiting systems do we anticipate more than one planet to be recovered. When these planets are recovered, we expect TESS to be a powerful tool to characterize transit timing variations. Using Kepler-88 (KOI-142) as an example, we show that TESS will improve measurements of planet-star mass ratios and orbital parameters, and significantly reduce the transit timing uncertainty in future years. Because TESS will be most sensitive to hot Jupiters, we research whether TESS will be able to detect tidal orbital decay in these systems. We find two confirmed planetary systems (Kepler-2 b and Kepler-13 b) and five candidate systems that will be good candidates to detect tidal decay.
119. Optical photometry and RVs of TOI-481b and TOI-892b
ID:
ivo://CDS.VizieR/J/AJ/160/235
Title:
Optical photometry and RVs of TOI-481b and TOI-892b
Short Name:
J/AJ/160/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of two new 10 day period giant planets from the Transiting Exoplanet Survey Satellite mission, whose masses were precisely determined using a wide diversity of ground-based facilities. TOI-481b and TOI-892b have similar radii (0.99{+/-}0.01R_Jup_ and 1.07{+/-}0.02R_Jup_, respectively), and orbital periods (10.3311days and 10.6266days, respectively), but significantly different masses (1.53{+/-}0.03M_Jup versus 0.95{+/-}0.07M_Jup_, respectively). Both planets orbit metal-rich stars ([Fe/H]=+0.26{+/-}0.05dex and [Fe/H]=+0.24{+/-}0.05 for TOI-481 and TOI-892, respectively) but at different evolutionary stages. TOI-481 is a M_*_=1.14{+/-}0.02M_{odot}_, R_*_=1.66{+/-}0.02R_{odot}_ G-type star (Teff=5735{+/-}72K), that with an age of 6.7Gyr, is in the turn-off point of the main sequence. TOI-892 on the other hand, is a F-type dwarf star (Teff=6261{+/-}80K), which has a mass of M_*_=1.28{+/-}0.03M_{odot}_ and a radius of R_*_=1.39{+/-}0.02R_{odot}_. TOI-481b and TOI-892b join the scarcely populated region of transiting gas giants with orbital periods longer than 10days, which is important to constrain theories of the formation and structure of hot Jupiters.
120. 10 parsec sample in the Gaia era
ID:
ivo://CDS.VizieR/J/A+A/650/A201
Title:
10 parsec sample in the Gaia era
Short Name:
J/A+A/650/A201
Date:
22 Feb 2022
Publisher:
CDS
Description:
The nearest stars provide a fundamental constraint for our understanding of stellar physics and the Galaxy. The nearby sample serves as an anchor where all objects can be seen and understood with precise data. This work is triggered by the most recent data release of the astrometric space mission Gaia and uses its unprecedented high precision parallax measurements to review the census of objects within 10pc. The first aim of this work was to compile all stars and brown dwarfs within 10pc observable by Gaia and compare it with the Gaia Catalogue of Nearby Stars as a quality assurance test. We complement the list to get a full 10 pc census, including bright stars, brown dwarfs, and exoplanets. We started our compilation from a query on all objects with a parallax larger than 100 mas using the Set of Identifications, Measurements, and Bibliography for Astronomical Data database (SIMBAD). We completed the census by adding companions, brown dwarfs with recent parallax measurements not in SIMBAD yet, and vetted exoplanets. The compilation combines astrometry and photometry from the recent Gaia Early Data Release 3 with literature magnitudes, spectral types, and line-of-sight velocities. We give a description of the astrophysical content of the 10pc sample. We find a multiplicity frequency of around 27%. Among the stars and brown dwarfs, we estimate that around 61% are M stars and more than half of the M stars are within the range from M3.0 V to M5.0 V. We give an overview of the brown dwarfs and exoplanets that should be detected in the next Gaia data releases along with future developments. We provide a catalogue of 540 stars, brown dwarfs, and exoplanets in 339 systems, within 10pc from the Sun. This list is as volume-complete as possible from current knowledge and it provides benchmark stars that can be used, for instance, to define calibration samples and to test the quality of the forthcoming Gaia releases. It also has a strong outreach potential.