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51. Four Jovian planets RV and activity indexes
ID:
ivo://CDS.VizieR/J/A+A/646/A131
Title:
Four Jovian planets RV and activity indexes
Short Name:
J/A+A/646/A131
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of planetary companions orbiting four low-luminosity giant stars with M* between 1.04 and 1.39M_{sun}_. All four host stars have been independently observed by the EXoPlanets aRound Evolved StarS (EXPRESS) program and the Pan-Pacific Planet Search (PPPS). The companion signals were revealed by multi-epoch precision radial velocities obtained in nearly a decade. The planetary companions exhibit orbital periods between ~1.2 and 7.1 years, minimum masses of m_p_*sini~1.8-3.7M_Jup_, and eccentricities between 0.08 and 0.42. With these four new systems, we have detected planetary companions to 11 out of the 37 giant stars that are common targets in the EXPRESS and PPPS. After excluding four compact binaries from the common sample, we obtained a fraction of giant planets (m_p_~1-2M_Jup_) orbiting within 5AU from their parent star of f=33.3^+9.0^_-7.1_%. This fraction is slightly higher than but consistent at the 1{sigma} level with previous results obtained by different radial velocity surveys. Finally, this value is substantially higher than the fraction predicted by planet formation models of gas giants around stars more massive than the Sun.
52. 68 Gaia DR2 ultra-short-period planet host stars
ID:
ivo://CDS.VizieR/J/AJ/160/138
Title:
68 Gaia DR2 ultra-short-period planet host stars
Short Name:
J/AJ/160/138
Date:
21 Oct 2021
Publisher:
CDS
Description:
It has been unambiguously shown both in individual systems and at the population level that hot Jupiters experience tidal inspiral before the end of their host stars main-sequence lifetimes. Ultra-short-period (USP) planets have orbital periods P<1 day, rocky compositions, and are expected to experience tidal decay on similar timescales to hot Jupiters if the efficiency of tidal dissipation inside their host stars parameterized as Q_*_' is independent of P and/or secondary mass M_p_. Any difference between the two classes of systems would reveal that a model with constant Q_*_' is insufficient. If USP planets experience tidal inspiral, then USP planet systems will be relatively young compared to similar stars without USP planets. Because it is a proxy for relative age, we calculate the Galactic velocity dispersions of USP planet candidate host and non-host stars using data from Gaia Data Release 2 supplemented with ground-based radial velocities. We find that main-sequence USP planet candidate host stars have kinematics consistent with similar stars in the Kepler field without observed USP planets. This indicates that USP planet hosts have similar ages to field stars and that USP planets do not experience tidal inspiral during the main-sequence lifetimes of their host stars. The survival of USP planets requires that Q_*_'>~10^7^ at P~0.7day and M_p_~2.6M{Earth}. This result demands that Q_*_' depend on the orbital period and/or mass of the secondary in the range 0.5day<~P<~5days and 1M{Earth}<~M_p_<~1000M{sun}.
53. Gaia-Kepler stellar properties catalog. II. Planets
ID:
ivo://CDS.VizieR/J/AJ/160/108
Title:
Gaia-Kepler stellar properties catalog. II. Planets
Short Name:
J/AJ/160/108
Date:
21 Oct 2021
Publisher:
CDS
Description:
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 dlogR_p/d_logM_{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_{Earth}_) to sub-Neptunes (1.8-3.5R_{Earth}_) increases from 0.61{+/-}0.09 at young ages (<1Gyr) to 1.00{+/-}0.10 at old ages (>1Gyr), 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}_{Earth}_) 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" (2.2R_{Earth}_<Rp<3.8R_{Earth}_, Fp>650F_{Earth}_) 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<20F_{Earth}_) 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.
54. Giant planet bulk and atmosphere metallicities
ID:
ivo://CDS.VizieR/J/ApJ/874/L31
Title:
Giant planet bulk and atmosphere metallicities
Short Name:
J/ApJ/874/L31
Date:
21 Oct 2021
Publisher:
CDS
Description:
Atmospheric characterization through spectroscopic analysis, an essential tool of modern exoplanet science, can benefit significantly from the context provided by the interior structure models. In particular, the planet's bulk metallicity, Zp, places an upper limit on the potential atmospheric metallicity. Here we construct interior structure models to derive Zp and atmospheric metallicity upper limits for 403 known transiting giant exoplanets. These limits are low enough that they can usefully inform atmosphere models. Additionally, we argue that comparing Zp to the observed atmospheric metallicity gives a useful measure of how well mixed metals are within the planet. This represents a new avenue for learning about planetary interiors. To aid in the future characterization of new planet discoveries we derive analytic prior predictions of atmosphere metallicity as a function of planet mass, and evaluate the effectiveness of our approach on Jupiter and Saturn. We include log-linear fits for approximating the metallicities of planets not in our catalog.
55. Gl617A and Gl96 radial velocity curves
ID:
ivo://CDS.VizieR/J/A+A/618/A103
Title:
Gl617A and Gl96 radial velocity curves
Short Name:
J/A+A/618/A103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of two exoplanets and a further tentative candidate around the M-dwarf stars Gl96 and Gl617A, based on radial velocity measurements obtained with the SOPHIE spectrograph at the Observatoire de Haute-Provence. Both stars were observed in the context of the SOPHIE exoplanet consortium's dedicated M-dwarf subprogramme, which aims to detect exoplanets around nearby M-dwarf stars through a systematic survey. For Gl96 we present the discovery of a new exoplanet at 73.9d with a minimum mass of 19.66 earth masses. Gl96b has an eccentricity of 0.44, placing it among the most eccentric planets orbiting M stars. For Gl617A we independently confirm a recently reported exoplanet at 86.7d with a minimum mass of 31.29 earth masses. Both Gl96 b and Gl617Ab are potentially within the habitable zone, though the high eccentricity of Gl96 b may take it too close to the star at periapsis.
56. HARPS radial velocity database
ID:
ivo://CDS.VizieR/J/A+A/636/A74
Title:
HARPS radial velocity database
Short Name:
J/A+A/636/A74
Date:
21 Oct 2021
Publisher:
CDS
Description:
The High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph is mounted since 2003 at the ESO 3.6m telescope in La Silla and provides state-of-the-art stellar radial velocity (RV) measurements with a precision down to ~1m/s. The spectra are extracted with a dedicated data-reduction software (DRS) and the RVs are computed by cross correlating with a numerical mask. The aim of this study is three-fold: (i) Create an easy access to the public HARPS RV data set. (ii) Apply the new public SpEctrum Radial Velocity AnaLyser (SERVAL) pipeline to the spectra, and produce a more precise RV data set. (iii) Check whether the precision of the RVs can be further improved by correcting for small nightly systematic effects. For each star observed with HARPS, we downloaded the publicly available spectra from the ESO archive, and recomputed the RVs with SERVAL. This was based on fitting each observed spectrum with a high signal-to-noise ratio template created by co-adding all the available spectra of that star. We then computed nightly zero points (NZPs) by averaging the RVs of quiet stars. Analysing the RVs of the most RV-quiet stars, whose RV scatter is <5m/s, we find that SERVAL RVs are on average more precise than DRS RVs by a few percent. Investigating the NZP time series, we find three significant systematic effects, whose magnitude is independent of the software used for the RV derivation: (i) stochastic variations with a magnitude of ~1m/s; (ii) longterm variations, with a magnitude of ~1m/s and a typical timescale of a few weeks; and (iii) 20-30NZPs significantly deviating by few m/s. In addition, we find small (<~1m/s) but significant intra-night drifts in DRS RVs before the 2015 intervention, and in SERVAL RVs after it. We confirm that the fibre exchange in 2015 caused a discontinuous RV jump, which strongly depends on the spectral type of the observed star: from ~14m/s for late F-type stars, to ~-3m/sx for M dwarfs. The combined effect of extracting the RVs with SERVAL and correcting them for the systematics we find is an improved average RV precision: ~5% improvement for spectra taken before the 2015 intervention, and ~15% improvement for spectra taken after it. To demonstrate the quality of the new RV data set, we present an updated orbital solution of the GJ 253 two-planet system. Our NZP-corrected SERVAL RVs can be retrieved from a user-friendly, public database. It provides more than 212000 RVs for about 3000 stars along with many auxiliary information, such as the NZP corrections, various activity indices, and DRS-CCF products.
57. HATSouth-K2 C7 transiting/eclipsing systems
ID:
ivo://CDS.VizieR/J/AJ/155/119
Title:
HATSouth-K2 C7 transiting/eclipsing systems
Short Name:
J/AJ/155/119
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the result of a campaign to monitor 25 HATSouth candidates using the Kepler space telescope during Campaign 7 of the K2 mission. We discover HATS-36b (EPIC 215969174b, K2-145b), an eccentric (e=0.105+/-0.028) hot Jupiter with a mass of 3.216+/-0.062 M_J_ and a radius of 1.235+/-0.043 R_J_, which transits a solar-type G0V star (V=14.386) in a 4.1752-day period. We also refine the properties of three previously discovered HATSouth transiting planets (HATS-9b, HATS-11b, and HATS-12b) and search the K2 data for TTVs and additional transiting planets in these systems. In addition, we also report on a further three systems that remain as Jupiter-radius transiting exoplanet candidates. These candidates do not have determined masses, however pass all of our other vetting observations. Finally, we report on the 18 candidates that we are now able to classify as eclipsing binary or blended eclipsing binary systems based on a combination of the HATSouth data, the K2 data, and follow-up ground-based photometry and spectroscopy. These range in periods from 0.7 day to 16.7 days, and down to 1.5 mmag in eclipse depths. Our results show the power of combining ground-based imaging and spectroscopy with higher precision space-based photometry, and serve as an illustration as to what will be possible when combining ground-based observations with TESS data.
58. HD 108236 CHEOPS light curves
ID:
ivo://CDS.VizieR/J/A+A/646/A157
Title:
HD 108236 CHEOPS light curves
Short Name:
J/A+A/646/A157
Date:
21 Oct 2021
Publisher:
CDS
Description:
The detection of a super-Earth and three mini-Neptunes transiting the bright (V=9.2mag) star HD108236 (also known as TOI-1233) was recently reported on the basis of TESS and ground-based light curves. We perform a first characterisation of the HD108236 planetary system through high-precision CHEOPS photometry and improve the transit ephemerides and system parameters. We characterise the host star through spectroscopic analysis and derive the radius with the infrared flux method.We constrain the stellar mass and age by combining the results obtained from two sets of stellar evolutionary tracks. We analyse the available TESS light curves and one CHEOPS transit light curve for each known planet in the system. We find that HD108236 is a Sun-like star with R*=0.877+/-0.008R_{sun}_, M*=0.869^+0.050^_0.048_M_{sun}_, and an age of 6.7^+4.0^_5.1_Gyr. We report the serendipitous detection of an additional planet, HD108236 f, in one of the CHEOPS light curves. For this planet, the combined analysis of the TESS and CHEOPS light curves leads to a tentative orbital period of about 29.5days. From the light curve analysis, we obtain radii of 1.615+/-0.051, 2.071+/-0.052, 2.539^+0.062^_0.065_, 3.083+/-0.052, and 2.017^+0.052^+0.057_R_{Earth}_ for planets HD108236 b to HD108236 f, respectively. These values are in agreement with previous TESS-based estimates, but with an improved precision of about a factor of two. We perform a stability analysis of the system, concluding that the planetary orbits most likely have eccentricities smaller than 0.1. We also employ a planetary atmospheric evolution framework to constrain the masses of the five planets, concluding that HD108236 b and HD108236 c should have an Earth-like density, while the outer planets should host a low mean molecular weight envelope. The detection of the fifth planet makes HD108236 the third system brighter than V=10mag to host more than four transiting planets. The longer time span enables us to significantly improve the orbital ephemerides such that the uncertainty on the transit times will be of the order of minutes for the years to come. A comparison of the results obtained from the TESS and CHEOPS light curves indicates that for a V~9mag solar-like star and a transit signal of 500ppm, one CHEOPS transit light curve ensures the same level of photometric precision as eight TESS transits combined, although this conclusion depends on the length and position of the gaps in the light curve.
59. HD 117214 debris disk polarization images
ID:
ivo://CDS.VizieR/J/A+A/635/A19
Title:
HD 117214 debris disk polarization images
Short Name:
J/A+A/635/A19
Date:
21 Oct 2021
Publisher:
CDS
Description:
Young stars with debris disks are the most promising targets for an exoplanet search because debris indicate a successful formation of planetary bodies. Debris disks can be shaped by planets into ring structures that give valuable indications on the presence and location of planets in the disk. We performed observations of the Sco-Cen F star HD 117214 to search for planetary companions and to characterize the debris disk structure. HD 117214 was observed with the SPHERE subsystems IRDIS, IFS, and ZIMPOL at optical and near-IR wavelengths using angular and polarimetric differential imaging techniques. This provided the first images of scattered light from the debris disk with the highest spatial resolution of 25mas and an inner working angle <0.1". With the observations with IRDIS and IFS we derived detection limits for substellar companions. The geometrical parameters of the detected disk were constrained by fitting 3D models for the scattering of an optically thin dust disk. Investigating the possible origin of the disk gap, we introduced putative planets therein and modeled the planet-disk and planet-planet dynamical interactions. The obtained planetary architectures were compared with the detection limit curves. The debris disk has an axisymmetric ring structure with a radius of 0.42(+/-0.01)" or ~45au and an inclination of 71(+/-2.5){deg} and exhibits a 0.4" (~40au) wide inner cavity. From the polarimetric data, we derive a polarized flux contrast for the disk of (Fpol)_disk_/F*=(3.1+/-1.2)x10^-4^ in the RI band. The fractional scattered polarized flux of the disk is eight times lower than the fractional IR flux excess. This ratio is similar to the one obtained for the debris disk HIP 79977, indicating that dust radiation properties are similar for these two disks. Inside the disk cavity we achieve high-sensitivity limits on planetary companions with a mass down to ~4M_J_ at projected radial separations between 0.2" and 0.4". We can exclude stellar companions at a radial separation larger than 75mas from the star.
60. HD193571 NaCo images
ID:
ivo://CDS.VizieR/J/A+A/627/A77
Title:
HD193571 NaCo images
Short Name:
J/A+A/627/A77
Date:
21 Oct 2021
Publisher:
CDS
Description:
The interaction between low-mass companions and the debris disks they reside in is still not fully understood. A debris disk can evolve due to self-stirring, a process in which planetesimals can excite their neighbours to the point of destructive collisions. On top of this, the presence of a companion could further stir the disk (companion-stirring). Additional information is necessary to understand this fundamental step in the formation and evolution of a planetary system, and at the moment of writing only a handful of systems are known in which both a companion and a debris disk have been detected and studied at the same time. Our primary goal is to augment the sample of such systems and understand the relative importance between self-stirring and companion-stirring. In the course of the VLT/NaCo-ISPY Imaging Survey for Planets around Young stars, we observed HD 193571, an A0 debris disk hosting star at a distance of 68 pc with an age between 60-170Myr. We obtained two sets of observations in L' band and a third epoch in H band using the GPI instrument at Gemini-South. A companion was detected in all three epochs at a projected separation of 11au (0.17-arcsec), and co-motion was confirmed through proper motion analysis. Given the inferred disk size of 120au, the companion appears to reside within the gap between the host star and the disk. Comparison between the L' and H band magnitude and evolutionary tracks suggests a mass of 0.31-0.39M_{sun}_. We discovered a previously unknown M-dwarf companion around HD 193571, making it the third low-mass stellar object discovered within a debris disk. Comparison to self- and companion-stirring models suggests that the companion is likely responsible for the stirring of the disk.