- 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/A+A/407/1139
- Title:
- RVB photometry of Kuiper-Belt object 1999 TD10
- Short Name:
- J/A+A/407/1139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric observations of the Kuiper-Belt object 1999 TD_10_ at different phase angles and for three different broad band filters (B, V and R). This object was observed with the Danish 1.54-m telescope of ESO in Chile during six different observing nights corresponding to a phase angle of 0.30, 0.37, 0.92, 3.43, 3.48 and 3.66{deg}. Extra observations were obtained in September 2002 with the VLT UT1/FORS1 combination to confirm that 1999 TD_10_ does not exhibit any cometary activity, and in October 2001 with the Sierra Nevada Observatory 1.50-m telescope in order to add relative magnitudes to improve the determination of the rotation period.
- ID:
- ivo://CDS.VizieR/J/AJ/159/44
- Title:
- RV curve of the metal-rich exoplanet host star XO-7
- Short Name:
- J/AJ/159/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Transiting planets orbiting bright stars are the most favorable targets for follow-up and characterization. We report the discovery of the transiting hot Jupiter XO-7b and of a second, massive companion on a wide orbit around a circumpolar, bright, and metal-rich G0 dwarf (V=10.52, T_eff_=6250{+/-}100K, [Fe/H]=0.432{+/-}0.057dex). We conducted photometric and radial velocity follow-up with a team of amateur and professional astronomers. XO-7b has a period of 2.8641424{+/-}0.0000043days, a mass of 0.709{+/-}0.034M_J_, a radius of 1.373{+/-}0.026R_J_, a density of 0.340{+/-}0.027g/cm^3^, and an equilibrium temperature of 1743{+/-}23K. Its large atmospheric scale height and the brightness of the host star make it well suited to atmospheric characterization. The wide-orbit companion is detected as a linear trend in radial velocities with an amplitude of ~100m/s over two years, yielding a minimum mass of 4M_J_; it could be a planet, a brown dwarf, or a low-mass star. The hot Jupiter orbital parameters and the presence of the wide-orbit companion point toward a high-eccentricity migration for the hot Jupiter. Overall, this system will be valuable to understand the atmospheric properties and migration mechanisms of hot Jupiters and will help constrain the formation and evolution models of gas giant exoplanets.
- ID:
- ivo://CDS.VizieR/J/AJ/162/181
- Title:
- RVel & Hipparcos positions of epsilon Eridani
- Short Name:
- J/AJ/162/181
- Date:
- 14 Mar 2022 06:39:08
- Publisher:
- CDS
- Description:
- {epsilon}Eridani is a young planetary system hosting a complex multibelt debris disk and a confirmed Jupiter-like planet orbiting at 3.48au from its host star. Its age and architecture are thus reminiscent of the early Solar System. The most recent study of Mawet et al., which combined radial-velocity data and Ms-band direct imaging upper limits, started to constrain the planet's orbital parameters and mass, but are still affected by large error bars and degeneracies. Here we make use of the most recent data compilation from three different techniques to further refine {epsilon}Eridani b's properties: RVs, absolute astrometry measurements from the Hipparcos and Gaia missions, and new Keck/NIRC2 Ms-band vortex coronagraph images. We combine this data in a Bayesian framework. We find a new mass, M_b_=0.66_-0.09_^+0.12^M_Jup_, and inclination, i=78.81_-22.41_^+29.34^deg, with at least a factor 2 of improvement over previous uncertainties. We also report updated constraints on the longitude of the ascending node, the argument of the periastron, and the time of periastron passage. With these updated parameters, we can better predict the position of the planet at any past and future epoch, which can greatly help define the strategy and planning of future observations and with subsequent data analysis. In particular, these results can assist the search for a direct detection with JWST and the Nancy Grace Roman Space Telescope's coronagraph instrument.
- ID:
- ivo://CDS.VizieR/J/AJ/155/79
- Title:
- RV & light curves data for 4 G-type dwarf stars
- Short Name:
- J/AJ/155/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four close-in transiting exoplanets (HATS-50b through HATS-53b), discovered using the HATSouth three-continent network of homogeneous and automated telescopes. These new exoplanets belong to the class of hot Jupiters and orbit G-type dwarf stars, with brightness in the range V=12.5-14.0 mag. While HATS-53 has many physical characteristics similar to the Sun, the other three stars appear to be metal-rich ([Fe/H]=0.2-0.3), larger, and more massive. Three of the new exoplanets, namely HATS-50b, HATS-51b, and HATS-53b, have low density (HATS-50b: 0.39+/-0.10 M_J_, 1.130+/-0.075 R_J_; HATS-51b: 0.768+/-0.045 M_J_, 1.41+/-0.19 R_J_; HATS-53b: 0.595+/-0.089 M_J_, 1.340+/-0.056 R_J_) and similar orbital periods (3.8297 days, 3.3489 days, 3.8538 days, respectively). Instead, HATS-52b is more dense (mass 2.24+/-0.15 M_J_ and radius 1.382+/-0.086 R_J_) and has a shorter orbital period (1.3667 days). It also receives an intensive radiation from its parent star and, consequently, presents a high equilibrium temperature (T_eq_=1834+/-73 K). HATS-50 shows a marginal additional transit feature consistent with an ultra-short-period hot super Neptune (upper mass limit 0.16 M_J_), which will be able to be confirmed with TESS photometry.
- ID:
- ivo://CDS.VizieR/J/AJ/123/3154
- Title:
- RV light curves of variable stars in Leo A
- Short Name:
- J/AJ/123/3154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for short-period variable stars in Leo A. We have found 92 candidate variables, including eight candidate RR Lyrae stars. From the RR Lyrae stars, we measure a distance modulus of (m-M)0=24.51+/-0.12, or 0.80+/-0.04Mpc. This discovery of RR Lyrae stars confirms for the first time the presence of an ancient (older than ~11Gyr) population in Leo A, accounting for at least 0.1% of the galaxy's V luminosity. We have also discovered a halo of old (more than ~2Gyr) stars surrounding Leo A, with a scale length roughly 50% larger than that of the dominant young population. We also report the discovery of a large population of Cepheids in Leo A. The median absolute magnitude of our Cepheid sample is M_V_=-1.1, fainter than 96% of SMC and 99% of LMC Cepheids. Their periods are also unusual, with three Cepheids that are deduced to be pulsating in the fundamental mode having periods of under 1 day. Upon examination, these characteristics of the Leo A Cepheid population appear to be a natural extension of the classical Cepheid period-luminosity relations to low metallicity, rather than being indicative of a large population of "anomalous" Cepheids. We demonstrate that the periods and luminosities are consistent with the expected values of low-metallicity blue helium-burning stars (BHeB's), which populate the instability strip at lower luminosities than do higher metallicity BHeB's. Observations of Leo A were obtained at the WIYN 3.5 m telescope on the nights of 20-22 December 2000, using the MIMO camera.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1337
- Title:
- RV of 111 Galactic halo stars in Virgo
- Short Name:
- J/AJ/140/1337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-slit radial velocity measurements for 111 stars in the direction of the Virgo Stellar Stream (VSS). The stars were photometrically selected to be probable main-sequence stars in the Galactic halo. When compared with the radial velocity distribution expected for the halo of the Milky Way, as well as the distribution seen in a control field, we observe a significant excess of negative velocity stars in the field, which can likely be attributed to the presence of a stellar stream.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/11
- Title:
- RV photon limits of well-characterized F-M stars
- Short Name:
- J/ApJS/247/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The determination of extrasolar planet masses with the radial velocity (RV) technique requires spectroscopic Doppler information from the planet's host star, which varies with stellar brightness and temperature. We analyze the Doppler information in spectra from dwarfs of spectral types F-M utilizing empirical information from HARPS and CARMENES data and model spectra. We revisit the question of whether optical or near-infrared instruments are more efficient for RV observations in low-mass stars, and we come to the conclusion that an optical setup (BVR bands) is more efficient than a near-infrared one (YJHK) in dwarf stars hotter than 3200K. We publish a catalog of 46480 well-studied F-M dwarfs in the solar neighborhood, and we compare its distribution to more than 1 million stars from Gaia DR2. For all stars, we estimate the RV photon noise achievable in typical observations under the assumption of no activity jitter and slow rotation. We find that with an ESPRESSO-like instrument at an 8m telescope, a photon noise limit of 10cm/s or lower can be reached in more than 280 stars in a 5 minute observation. At 4m telescopes, a photon noise limit of 1m/s can be reached in a 10 minute exposure in approximately 10000 predominantly Sun-like stars with a HARPS-like (optical) instrument. The same applies to ~3000 stars for a red optical setup that covers the R and I bands and ~700 stars for a near-infrared instrument. For the latter two, many of the targets are nearby M dwarfs. Finally, we identify targets in which Earth-mass planets within the liquid water habitable zone can cause RV amplitudes comparable to the RV photon noise. Assuming the same exposure times as above, we find that an ESPRESSO-like instrument can reach this limit for 1M_{Earth}_ planets in more than 1000 stars. The optical, red optical, and near-infrared configurations reach the limit for 2M_{Earth}_ planets in approximately 500, 700, and 200 stars, respectively. An online tool is provided to estimate the RV photon noise as a function of stellar temperature and brightness and wavelength coverage.
- 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/159/145
- Title:
- RVs and opt. photometry of the host star TOI-677
- Short Name:
- J/AJ/159/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of TOI-677b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677b has a mass of M_p_=1.236_-0.067_^+0.069^M_J_, a radius of R_P_=1.170{+/-}0.03R_J_, and orbits its bright host star (V=9.8mag) with an orbital period of 11.23660{+/-}0.00011d, on an eccentric orbit with e=0.435{+/-}0.024. The host star has a mass of M_*_=1.181{+/-}0.058M_{sun}_, a radius of R_*_=1.28_-0.03_^+0.03^R_{sun}_, an age of 2.92_-0.73_^+0.80^Gyr and solar metallicity, properties consistent with a main-sequence late-F star with T_eff_=6295{+/-}77K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677b system is a well-suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.