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Start Over Subject exoplanets Validation Level 2
211. Light curve of K2-292 (HD 119130)
ID:
ivo://CDS.VizieR/J/A+A/623/A114
Title:
Light curve of K2-292 (HD 119130)
Short Name:
J/A+A/623/A114
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery and characterisation of a new transiting planet from Campaign 17 of the Kepler extended mission K2. The planet K2-292 b is a warm sub-Neptune on a 17-d orbit around a bright (V=9.9mag) solar-like G3 V star with a mass and radius of Ms=1.00+/-0.03M_{sun}_ and Rs=1.09+/-0.03R_{sun}_ respectively. We model simultaneously the K2 photometry and CARMENES spectroscopic data and derive a radius of Rp=2.63_-0.10+^+0.12^R_{earth}_ and mass of Mp=24.5_-4.4_^+4.4^M_{earth}_, yielding a mean density of 7.4_-1.5_^+1.6^g/cm^3^, which makes it one of the densest sub-Neptune planets known to date. We also detect a linear trend in radial velocities of HD 119130 that suggests a long-period companion with a minimum mass on the order of 33M_{earth}_. If confirmed, it would support a formation scenario of K2-292 b by migration caused by Kozai-Lidov oscillations.
212. Light curve of OGLE-2018-BLG-0677
ID:
ivo://CDS.VizieR/J/AJ/159/256
Title:
Light curve of OGLE-2018-BLG-0677
Short Name:
J/AJ/159/256
Date:
08 Dec 2021
Publisher:
CDS
Description:
We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star-planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super- Earth/sub-Neptune with a mass of M_planet_=3.96_-2.66_^+5.88^M_{Earth}_. The host star has a mass of M_host_=0.12_-0.08_^+0.14^M_{odot}_. The projected separation for the inner and outer solutions are 0.63_-0.17_^+0.20^au and 0.72_-0.19_^+0.23^au respectively. At {Delta}{chi}^2^={chi}^2^(1L1S-{chi}^2^(2L1S)=46, this is by far the lowest {Delta}{chi}^2^ for any securely detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump."
213. Light curve & radial velocities for TOI-172
ID:
ivo://CDS.VizieR/J/AJ/157/191
Title:
Light curve & radial velocities for TOI-172
Short Name:
J/AJ/157/191
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of TOI-172 b from the Transiting Exoplanet Survey Satellite (TESS) mission, a massive hot Jupiter transiting a slightly evolved G star with a 9.48-day orbital period. This is the first planet to be confirmed from analysis of only the TESS full frame images, because the host star was not chosen as a two-minute cadence target. From a global analysis of the TESS photometry and follow-up observations carried out by the TESS Follow-up Observing Program Working Group, TOI-172 (TIC 29857954) is a slightly evolved star with an effective temperature of T_eff_=5645+/-50 K, a mass of M_*_=1.128_-0.061_^+0.065^ M_{sun}_, radius of R_*_=1.777_-0.044_^+0.047^ R_{sun}_, a surface gravity of log g_*_=3.993_-0.028_^+0.027^, and an age of 7.4_-1.5_^+1.6^ Gyr. Its planetary companion (TOI-172 b) has a radius of R_P_=0.965_-0.029_^+0.032^ R_J_, a mass of M_P_=5.42_-0.20_^+0.22^ M_J_, and is on an eccentric orbit (e=0.3806_-0.0090_^+0.0093^). TOI-172 b is one of the few known massive giant planets on a highly eccentric short-period orbit. Future study of the atmosphere of this planet and its system architecture offer opportunities to understand the formation and evolution of similar systems.
214. Light curves and RVs of WASP-174
ID:
ivo://CDS.VizieR/J/A+A/633/A30
Title:
Light curves and RVs of WASP-174
Short Name:
J/A+A/633/A30
Date:
21 Oct 2021
Publisher:
CDS
Description:
The transiting exoplanetary system WASP-174 was reported to be composed by a main-sequence F star and a giant planet, WASP-174b. However only an upper limit was placed on the planet mass, and a highly uncertain planetary radius was determined. We aim to better characterise both the star and the planet and precisely measure their orbital and physical parameters. In order to constrain the mass of the planet, we obtained new measurements of the radial velocity of the star and joined them with those from the discovery paper. Photometric data Q1 from the HATSouth survey and new multi-band, high-quality (precision reached up to 0.37mmag) photometric follow-up observations of transit events were acquired and analysed for getting accurate photometric parameters. We fit the model to all the observations, including data from the TESS space telescope, in two different modes: incorporating the stellar isochrones into the fit, and using an empirical method to get the stellar parameters. The two modes resulted to be consistent with each other. We confirm the grazing nature of the WASP-174b transits, which is also corroborated by simultaneously observing the transit through four optical bands and noting how the transit depth changes due to the limb-darkening effect. We estimate that 76% of the disk of the planet actually eclipses the parent star at mid-transit of its transit events. We find that WASP-174b is a highly-inflated hot giant planet with a mass of 0.330M_Jup_ and a radius of 1.435R_Jup_, and is therefore a good target for transmission-spectroscopy observations. With a density of 0.135g/cm^3^, it is amongst the lowest-density planets ever discovered with precisely measured mass and radius.
215. Light curve segments of 22 host stars with TESS
ID:
ivo://CDS.VizieR/J/AJ/160/155
Title:
Light curve segments of 22 host stars with TESS
Short Name:
J/AJ/160/155
Date:
10 Dec 2021
Publisher:
CDS
Description:
We present a systematic phase curve analysis of known transiting systems observed by the Transiting Exoplanet Survey Satellite (TESS) during year one of the primary mission. Using theoretical predictions for the amplitude of the planetary longitudinal atmospheric brightness modulation, stellar ellipsoidal distortion and Doppler boosting, as well as brightness considerations to select targets with likely detectable signals, we applied a uniform data processing and light-curve modeling framework to fit the full-orbit phase curves of 22 transiting systems with planet-mass or brown dwarf companions, including previously published systems. Statistically significant secondary eclipse depths and/or atmospheric brightness modulation amplitudes were measured for HIP65A, WASP-18, WASP-19, WASP-72, WASP-100, WASP-111, WASP-121, and WASP-122/KELT-14. For WASP-100b, we found marginal evidence that the brightest region of the atmosphere is shifted eastward away from the substellar point. We detected significant ellipsoidal distortion signals in the light curves of HIP65A, TOI-503, WASP-18, and WASP-30, with HIP65A, TOI-503 and WASP-18 also exhibiting Doppler boosting. The measured amplitudes of these signals agree with the predictions of theoretical models. Combining the optical secondary eclipse depths with previously published Spitzer 3.6 and 4.5{mu}m measurements, we derived dayside brightness temperatures and visible-light geometric albedos for a subset of the analyzed systems. We also calculated updated transit ephemerides combining the transit timings from the TESS light curves with previous literature values.
216. Light curves of WASP-74
ID:
ivo://CDS.VizieR/J/MNRAS/485/5168
Title:
Light curves of WASP-74
Short Name:
J/MNRAS/485/5168
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present broad-band photometry of 11 planetary transits of the hot Jupiter WASP-74 b, using three medium-class telescopes and employing the telescope-defocusing technique. Most of the transits were monitored through I filters and one was simultaneously observed in five optical (U, g', r', i', z') and three near-infrared (J, H, K) passbands, for a total of 18 light curves. We also obtained new high-resolution spectra of the host star. We used these new data to review the orbital and physical properties of the WASP-74 planetary system. We were able to better constrain the main system characteristics, measuring smaller radius and mass for both the hot Jupiter and its host star than previously reported in the literature. Joining our optical data with those taken with the HST in the near infrared, we built up an observational transmission spectrum of the planet, which suggests the presence of strong optical absorbers, as TiO and VO gases, in its atmosphere.
217. Light curves of WASP-52
ID:
ivo://CDS.VizieR/J/MNRAS/465/843
Title:
Light curves of WASP-52
Short Name:
J/MNRAS/465/843
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM+gemc codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be {lambda}=3.8+/-8.4{deg}. We also determined the true orbital obliquity, {psi}=20+/-50{deg}, which is, although very uncertain, the first measurement of {psi} purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.
218. Lithium abundances of KOIs from CKS spectra
ID:
ivo://CDS.VizieR/J/ApJ/855/115
Title:
Lithium abundances of KOIs from CKS spectra
Short Name:
J/ApJ/855/115
Date:
21 Oct 2021
Publisher:
CDS
Description:
The lithium doublet at 6708{AA} provides an age diagnostic for main sequence FGK dwarfs. We measured the abundance of lithium in 1305 stars with detected transiting planets from the Kepler mission using high-resolution spectroscopy. Our catalog of lithium measurements from this sample has a range of abundance from A(Li)=3.11+/-0.07 to an upper limit of -0.84dex. For a magnitude-limited sample that comprises 960 of the 1305 stars, our Keck-HIRES spectra have a median signal-to-noise ratio of 45 per pixel at ~6700{AA} with spectral resolution {lambda}/{Delta}{lambda}=R=55000. We identify 80 young stars that have A(Li) values greater than the Hyades at their respective effective temperatures; these stars are younger than ~650Myr, the approximate age of the Hyades. We then compare the distribution of A(Li) with planet size, multiplicity, orbital period, and insolation flux. We find larger planets preferentially in younger systems, with an A-D two-sided test p-value=0.002, a>3{sigma} confidence that the older and younger planet samples do not come from the same parent distribution. This is consistent with planet inflation/photoevaporation at early ages. The other planet parameters (Kepler planet multiplicity, orbital period, and insolation flux) are uncorrelated with age.
219. Low-mass stars from the first two TESS sectors
ID:
ivo://CDS.VizieR/J/AJ/158/81
Title:
Low-mass stars from the first two TESS sectors
Short Name:
J/AJ/158/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
Continuous data releases throughout the Transiting Exoplanet Survey Satellite (TESS) primary mission will provide unique opportunities for the exoplanet community at large to contribute to maximizing TESS's scientific return via the discovery and validation of transiting planets. This paper introduces our independent pipeline for the detection of periodic transit events along with the results of its inaugural application to the recently released 2 minute light curves of low-mass stars from the first two TESS sectors. The stellar parameters within our sample are refined using precise parallax measurements from the Gaia DR2 (Cat. I/345), which reduce the number of low-mass stars in our sample relative to those listed in the TESS Input Catalog. In lieu of the follow-up observations required to confirm or refute the planetary nature of transit-like signals, a validation of transit-like events flagged by our pipeline is performed statistically. The resulting vetted catalog contains eight probable blended eclipsing binaries, eight known TOIs, plus seven new planet candidates (PCs) smaller than 4 Earth radii. This work demonstrates the ability of our pipeline to detect sub-Neptune-sized PCs, which to date represent some of the most attractive targets for future atmospheric characterization via transmission or thermal emission spectroscopy and for radial velocity efforts aimed at the completion of the TESS level one requirement to deliver 50 planets smaller than 4 Earth radii with measured masses.
220. LP714-47 (TOI 442) radial velocity curve
ID:
ivo://CDS.VizieR/J/A+A/644/A127
Title:
LP714-47 (TOI 442) radial velocity curve
Short Name:
J/A+A/644/A127
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of a Neptune-like planet (LP714-47b, P=4.05204d, m=30.8+/-1.5 M_Earth_, r=4.7+/-0.3 R_Earth_) located in the 'hot Neptune desert'. Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TUBITAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP714-47b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP714-47 is a slowly rotating early M dwarf (T_eff_=3950+/-51K) with a mass of 0.59+/-0.02M_{sun}_ and a radius of 0.58+/-0.02R_{sun}_. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.