- ID:
- ivo://CDS.VizieR/J/A+A/567/A14
- Title:
- RV and g'z' transits of KOI-1089b/Kepler-418b
- Short Name:
- J/A+A/567/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1M_jup_ on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~40% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110+/-0.0025, more than 25% more than the 0.087 measured by Kepler, leading to a radius of 1.20+/-0.16R_jup_ instead of the 0.94R_jup_ measured by the Kepler team. This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors and binary companions that do not affect the classification of the transiting object but can have a very significant effect on the perceived planetary radius.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/1503
- Title:
- RV curves of WASP-16, 25 and 31
- Short Name:
- J/MNRAS/423/1503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new measurements of the Rossiter-McLaughlin (RM) effect for three Wide Angle Search for transiting Planets (WASP) planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of their complete sets of photometric and spectroscopic data.
- ID:
- ivo://CDS.VizieR/J/A+A/639/A35
- Title:
- RV jitter and photometric var. correlation
- Short Name:
- J/A+A/639/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Characterizing the relation between stellar photometric variability and radial velocity (RV) jitter can help us to better understand the physics behind these phenomena. The current and upcoming high precision photometric surveys such as TESS, CHEOPS, and PLATO will provide the community with thousands of new exoplanet candidates. As a consequence, the presence of such a correlation is crucial in selecting the targets with the lowest RV jitter for efficient RV follow-up of exoplanetary candidates. Studies of this type are also crucial to design optimized observational strategies to mitigate RV jitter when searching for Earth-mass exoplanets. Aims. Our goal is to assess the correlation between high-precision photometric variability measurements and high-precision RV jitter over different time scales. We analyze 171 G, K, and M stars with available TESS high precision photometric time-series and HARPS precise RVs. We derived the stellar parameters for the stars in our sample and measured the RV jitter and photometric variability. We also estimated chromospheric CaII H & K activity indicator log(R'_HK_), vsini, and the stellar rotational period. Finally, we evaluate how different stellar parameters and an RV sampling subset can have an impact on the potential correlations. We find a varying correlation between the photometric variability and RV jitter as function of time intervals between the TESS photometric observation and HARPS RV. As the time intervals of the observations considered for the analysis increases, the correlation value and significance becomes smaller and weaker, to the point that it becomes negligible. We also find that for stars with a photometric variability above 6.5 ppt the correlation is significantly stronger. We show that such a result can be due to the transition between the spot-dominated and the faculae-dominated regime. We quantified the correlations and updated the relationship between chromospheric CaII H & K activity indicator log(R'_HK_) and RV jitter.
- ID:
- ivo://CDS.VizieR/J/AN/338/671
- Title:
- RV measurements of eight spectroscopic binaries
- Short Name:
- J/AN/338/671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since early 2015 a new radial velocity monitoring campaign is going on at the University Observatory Jena. The aim of this project is to obtain current radial velocity measurements of selected single-lined spectroscopic binary systems, to re-determine and/or constrain their orbital solutions.
- ID:
- ivo://CDS.VizieR/J/AJ/157/55
- Title:
- RVs and light curves for HATS-60-HATS-69
- Short Name:
- J/AJ/157/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 10 transiting extrasolar planets by the HATSouth survey. The planets range in mass from the super-Neptune HATS-62b, with M_p_<0.179 M_J_, to the super-Jupiter HATS-66b, with M_p_=5.33 M_J_, and in size from the Saturn HATS-69b, with R_p_=0.94 R_J_, to the inflated Jupiter HATS-67b, with R_p_=1.69 R_J_. The planets have orbital periods between 1.6092 days (HATS-67b) and 7.8180 days (HATS-61b). The hosts are dwarf stars with masses ranging from 0.89 M_{sun}_ (HATS-69) to 1.56 M_{sun}_ (HATS-64) and have apparent magnitudes between V=12.276+/-0.020 mag (HATS-68) and V=14.095+/-0.030 mag (HATS-66). The super-Neptune HATS-62b is the least massive planet discovered to date with a radius larger than Jupiter. Based largely on the Gaia DR2 distances and broadband photometry, we identify three systems (HATS-62, HATS-64, and HATS-65) as having possible unresolved binary star companions. We discuss in detail our methods for incorporating the Gaia DR2 observations into our modeling of the system parameters and into our blend analysis procedures.
- ID:
- ivo://CDS.VizieR/J/AJ/160/222
- Title:
- RVs and RI-photometry of HATS-37 and HATS-38
- Short Name:
- J/AJ/160/222
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- We report the discovery of two transiting Neptunes by the HATSouth survey. The planet HATS-37Ab has a mass of 0.099{+/-}0.042M_Jup_ (31.5{+/-}13.4M{Earth}) and a radius of 0.606{+/-}0.016R_Jup_, and is on a P=4.3315day orbit around a V=12.266{+/-}0.030mag, 0.843_-0.012_^+0.017^M{odot} star with a radius of 0.877_-0.012_^+0.019^R{odot}. We also present evidence that the star HATS-37A has an unresolved stellar companion HATS-37B, with a photometrically estimated mass of 0.654{+/-}0.033M{odot}. The planet HATS-38b has a mass of 0.074{+/-}0.011M_Jup_ (23.5{+/-}3.5M{Earth}) and a radius of 0.614{+/-}0.017R_Jup_, and is on a P=4.3750day orbit around a V=12.411{+/-}0.030mag, 0.890_-0.012_^+0.016^M{odot} star with a radius of 1.105{+/-}0.016 R{odot}. Both systems appear to be old, with isochrone-based ages of 11.46_-1.45_^+0.79^Gyr, and 11.89{+/-}0.60Gyr, respectively. Both HATS-37Ab and HATS-38b lie in the Neptune desert and are thus examples of a population with a low occurrence rate. They are also among the lowest-mass planets found from ground-based wide-field surveys to date.
- ID:
- ivo://CDS.VizieR/J/AJ/155/159
- Title:
- RVs of the late-T dwarf GL 758 B host star
- Short Name:
- J/AJ/155/159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gl 758 B is a late-T dwarf orbiting a metal-rich Sun-like star at a projected separation of {rho}~1.6" (25 au). We present four epochs of astrometry of this system with NIRC2 at Keck Observatory spanning 2010 to 2017 together with 630 radial velocities (RVs) of the host star acquired over the past two decades from McDonald Observatory, Keck Observatory, and the Automated Planet Finder at Lick Observatory. The RVs reveal that Gl 758 is accelerating with an evolving rate that varies between 2 and 5 m/s/yr, consistent with the expected influence of the imaged companion Gl 758 B. A joint fit of the RVs and astrometry yields a dynamical mass of 42_-7_^+19^ M_Jup_ for the companion with a robust lower limit of 30.5 M_Jup_ at the 4-{sigma} level. Gl 758 B is on an eccentric orbit (e=0.26-0.67 at 95% confidence) with a semimajor axis of a=21.1_-1.3_^+2.7^ au and an orbital period of P=96_-9_^+21^ yr, which takes it within ~9 au from its host star at periastron passage. Substellar evolutionary models generally underpredict the mass of Gl 758 B for nominal ages of 1-6 Gyr that have previously been adopted for the host star. This discrepancy can be reconciled if the system is older - which is consistent with activity indicators and recent isochrone fitting of the host star - or alternatively if the models are systematically overluminous by ~0.1-0.2 dex. Gl 758 B is currently the lowest-mass directly imaged companion inducing a measured acceleration on its host star. In the future, bridging RVs and high-contrast imaging with the next generation of extremely large telescopes and space-based facilities will open the door to the first dynamical mass measurements of imaged exoplanets.
- ID:
- ivo://CDS.VizieR/J/AJ/156/89
- Title:
- RVs & predicted transit-times for the K2-24 system
- Short Name:
- J/AJ/156/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- While planets between the size of Uranus and Saturn are absent within the solar system, the star K2-24 hosts two such planets, K2-24b and c, with radii equal to 5.4 R_{Earth}_ and 7.5 R_{Earth}_, respectively. The two planets have orbital periods of 20.9 days and 42.4 days, residing only 1% outside the nominal 2:1 mean-motion resonance. In this work, we present results from a coordinated observing campaign to measure planet masses and eccentricities that combines radial velocity measurements from Keck/HIRES and transit-timing measurements from K2 and Spitzer. K2-24b and c have low, but nonzero, eccentricities of e_1_~e_2_~0.08. The low observed eccentricities provide clues to the formation and dynamical evolution of K2-24b and K2-24c, suggesting that they could be the result of stochastic gravitational interactions with a turbulent protoplanetary disk, among other mechanisms. K2-24b and c are 19.0_-2.1_^+2.2^ M_{Earth}_ and 15.4_-1.8_^+1.9^ M_{Earth}_, respectively; K2-24c is 20% less massive than K2-24b, despite being 40% larger. Their large sizes and low masses imply large envelope fractions, which we estimate at 26_-3_^+3^ % and 52_-3_^+5^ %. In particular, K2-24c's large envelope presents an intriguing challenge to the standard model of core-nucleated accretion that predicts the onset of runaway accretion when f_env_~50%.
- ID:
- ivo://CDS.VizieR/J/ApJ/787/110
- Title:
- SAGA: Stromgren survey of seismic KIC stars
- Short Name:
- J/ApJ/787/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asteroseismology has the capability of precisely determining stellar properties that would otherwise be inaccessible, such as radii, masses, and thus ages of stars. When coupling this information with classical determinations of stellar parameters, such as metallicities, effective temperatures, and angular diameters, powerful new diagnostics for Galactic studies can be obtained. The ongoing Stromgren survey for Asteroseismology and Galactic Archaeology (SAGA) has the goal of transforming the Kepler field into a new benchmark for Galactic studies, similar to the solar neighborhood. Here we present the first results from a stripe centered at a Galactic longitude of 74{deg} and covering latitude from about 8{deg} to 20{deg}, which includes almost 1000 K giants with seismic information and the benchmark open cluster NGC 6819. We describe the coupling of classical and seismic parameters, the accuracy as well as the caveats of the derived effective temperatures, metallicities, distances, surface gravities, masses, and radii. Confidence in the achieved precision is corroborated by the detection of the first and secondary clumps in a population of field stars with a ratio of 2 to 1 and by the negligible scatter in the seismic distances among NGC 6819 member stars. An assessment of the reliability of stellar parameters in the Kepler Input Catalog is also performed, and the impact of our results for population studies in the Milky Way is discussed, along with the importance of an all-sky Stromgren survey.
1010. Sco OB2 association
- ID:
- ivo://CDS.VizieR/J/A+A/382/92
- Title:
- Sco OB2 association
- Short Name:
- J/A+A/382/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the dependence of (visual) binarity characteristics on the primary component mass, we selected all stars of spectral type B in Sco OB2 association and searched for near-infrared companions to them with ADONIS and Coronograph. The data acquisition and companions measurement results are described; the mass ratio distribution f(q)=q**(-0.5) is derived using the PMS stars evolution tracks. Target stars J- and K-magnitudes are presented in Table 1; differential photometry and astrometry results for secondary companions and background sources in sky-offset fields are given in Table 2 and 3, respectively.
