- ID:
- ivo://CDS.VizieR/J/AJ/154/188
- Title:
- Radial velocities and photometry of K2-114&K2-115
- Short Name:
- J/AJ/154/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first results from a search for transiting warm Jupiter exoplanets-gas giant planets receiving stellar irradiation below about 10^8^ erg/s/cm^2^, equivalent to orbital periods beyond about 10 days around Sun-like stars. We have discovered two transiting warm Jupiter exoplanets initially identified as transiting candidates in K2 photometry. K2-114b has a mass of 1.85_-0.22_^+0.23^ M_J_, a radius of 0.942_-0.020_^+0.032^ R_J_, and an orbital period of 11.4 days. K2-115b has a mass of 0.84_-0.20_^+0.18^ M_J_, a radius of 1.115_-0.061_^+0.057^ R_J_, and an orbital period of 20.3 days. Both planets are among the longest-period transiting gas giant planets with a measured mass, and they are orbiting relatively old host stars. Both planets are not inflated, as their radii are consistent with theoretical expectations. Their position in the planet radius-stellar irradiation diagram is consistent with the scenario where the radius-irradiation correlation levels off below about 10^8^ erg/s/cm^2^, suggesting that for warm Jupiters stellar irradiation does not play a significant role in determining the planet radius. We also report our identification of another K2 transiting warm Jupiter candidate, EPIC 212504617, as a false positive.
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- ID:
- ivo://CDS.VizieR/J/AJ/158/181
- Title:
- Radial velocities and S-index values for HR 5183
- Short Name:
- J/AJ/158/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on two decades of radial velocity (RV) observations using Keck/High Resolution Echelle Spectrometer (HIRES) and McDonald/Tull, and more recent observations using the Automated Planet Finder, we found that the nearby star HR 5183 (HD 120066) hosts a 3 M_J_ minimum mass planet with an orbital period of 74_-22_^+43^ yr. The orbit is highly eccentric (e~0.84), shuttling the planet from within the orbit of Jupiter to beyond the orbit of Neptune. Our careful survey design enabled high cadence observations before, during, and after the planet's periastron passage, yielding precise orbital parameter constraints. We searched for stellar or planetary companions that could have excited the planet's eccentricity, but found no candidates, potentially implying that the perturber was ejected from the system. We did identify a bound stellar companion more than 15000 au from the primary, but reasoned that it is currently too widely separated to have an appreciable effect on HR 5183 b. Because HR 5183 b's wide orbit takes it more than 30 au (1") from its star, we also explored the potential of complimentary studies with direct imaging or stellar astrometry. We found that a Gaia detection is very likely, and that imaging at 10 {mu}m is a promising avenue. This discovery highlights the value of long-baseline RV surveys for discovering and characterizing long-period, eccentric Jovian planets. This population may offer important insights into the dynamical evolution of planetary systems containing multiple massive planets.
- ID:
- ivo://CDS.VizieR/J/AJ/157/192
- Title:
- Radial velocities and transit times for KOI 4
- Short Name:
- J/AJ/157/192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of thousands of planetary systems by Kepler has demonstrated that planets are ubiquitous. However, a major challenge has been the confirmation of Kepler planet candidates, many of which still await confirmation. One of the most enigmatic examples is KOI 4.01, Kepler's first discovered planet candidate detection (as KOI 1.01, 2.01, and 3.01 were known prior to launch). Here we present the confirmation and characterization of KOI 4.01 (now Kepler-1658), using a combination of asteroseismology and radial velocities. Kepler-1658 is a massive, evolved subgiant (M_*_=1.45+/-0.06 M_{sun}_, R_*_=2.89+/-0.12 R_{sun}_) hosting a massive (M_p_=5.88+/-0.47 M_J_, R_p_=1.07+/-0.05 R_J_) hot Jupiter that orbits every 3.85 days. Kepler-1658 joins a small population of evolved hosts with short-period (~<100 days) planets and is now the closest known planet in terms of orbital period to an evolved star. Because of its uniqueness and short orbital period, Kepler-1658 is a new benchmark system for testing tidal dissipation and hot Jupiter formation theories. Using all four years of the Kepler data, we constrain the orbital decay rate to be P=<-0.42 s/yr, corresponding to a strong observational limit of Q'_*_>=4.826x10^3^ for the tidal quality factor in evolved stars. With an effective temperature of T_eff_~6200 K, Kepler-1658 sits close to the spin-orbit misalignment boundary at ~6250 K, making it a prime target for follow-up observations to better constrain its obliquity and to provide insight into theories for hot Jupiter formation and migration.
- ID:
- ivo://CDS.VizieR/J/AJ/154/122
- Title:
- Radial velocities for the HD 3167 system
- Short Name:
- J/AJ/154/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD 3167 is a bright (V=8.9), nearby K0 star observed by the NASA K2 mission (EPIC 220383386), hosting two small, short-period transiting planets. Here we present the results of a multi-site, multi-instrument radial-velocity campaign to characterize the HD 3167 system. The masses of the transiting planets are 5.02+/-0.38 M_{earth}_ for HD 3167 b, a hot super-Earth with a likely rocky composition ({rho}_b_=5.60_-1.43_^+2.15^ g/cm^3^), and 9.80_-1.24_^+1.30^ M_{earth}_ for HD 3167 c, a warm sub-Neptune with a likely substantial volatile complement ({rho}_c_=1.97_-0.59_^+0.94^ g/cm^3^). We explore the possibility of atmospheric composition analysis and determine that planet c is amenable to transmission spectroscopy measurements, and planet b is a potential thermal emission target. We detect a third, non-transiting planet, HD 3167 d, with a period of 8.509+/-0.045 d (between planets b and c) and a minimum mass of 6.90+/-0.71 M_{earth}_. We are able to constrain the mutual inclination of planet d with planets b and c: we rule out mutual inclinations below 1.3{deg} because we do not observe transits of planet d. From 1.3{deg} to 40{deg}, there are viewing geometries invoking special nodal configurations, which result in planet d not transiting some fraction of the time. From 40{deg} to 60{deg}, Kozai-Lidov oscillations increase the system's instability, but it can remain stable for up to 100 Myr. Above 60{deg}, the system is unstable. HD 3167 promises to be a fruitful system for further study and a preview of the many exciting systems expected from the upcoming NASA TESS mission.
- ID:
- ivo://CDS.VizieR/J/AJ/154/181
- Title:
- Radial velocities for the star HD 34445
- Short Name:
- J/AJ/154/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new precision radial velocity (RV) data set that reveals a multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists of 333 precision RV observations, 56 of which were previously published and 277 of which are new data from the Keck Observatory, Magellan at Las Campanas Observatory, and the Automated Planet Finder at Lick Observatory. These data indicate the presence of six planet candidates in Keplerian motion about the host star with periods of 1057, 215, 118, 49, 677, and 5700 days, and minimum masses of 0.63, 0.17, 0.1, 0.05, 0.12, and 0.38 MJ, respectively. The HD 34445 planetary system, with its high degree of multiplicity, its long orbital periods, and its induced stellar RV half-amplitudes in the range 2 m/s~<K~<5 m/s is fundamentally unlike either our own solar system (in which only Jupiter and Saturn induce significant reflex velocities for the Sun), or the Kepler multiple-transiting systems (which tend to have much more compact orbital configurations).
- ID:
- ivo://CDS.VizieR/J/AJ/155/112
- Title:
- Radial velocities & light curves for HATS-43-HATS-46
- Short Name:
- J/AJ/155/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four short-period extrasolar planets transiting moderately bright stars from photometric measurements of the HATSouth network coupled to additional spectroscopic and photometric follow-up observations. While the planet masses range from 0.26 to 0.90 M_J_, the radii are all approximately a Jupiter radii, resulting in a wide range of bulk densities. The orbital period of the planets ranges from 2.7 days to 4.7 days, with HATS-43b having an orbit that appears to be marginally non-circular (e=0.173+/-0.089). HATS-44 is notable for having a high metallicity ([Fe/H]=0.320+/-0.071). The host stars spectral types range from late F to early K, and all of them are moderately bright (13.3<V<14.4), allowing the execution of future detailed follow-up observations. HATS-43b and HATS-46b, with expected transmission signals of 2350 ppm and 1500 ppm, respectively, are particularly well suited targets for atmospheric characterization via transmission spectroscopy.
- ID:
- ivo://CDS.VizieR/J/AJ/158/197
- Title:
- Radial velocities & light curves of KELT-24
- Short Name:
- J/AJ/158/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of KELT-24 b, a massive hot Jupiter orbiting a bright (V=8.3 mag, K=7.2 mag) young F-star with a period of 5.6 days. The host star, KELT-24 (HD 93148), has a T_eff_=6509_-49_^+50^ K, a mass of M_*_=1.460_-0.059_^+0.055^ M_{sun}_, a radius of R_*_=1.506+/-0.022 R_{sun}_, and an age of 0.78_-0.42_^+0.61^ Gyr. Its planetary companion (KELT-24 b) has a radius of R_P_=1.272+/-0.021 R_J_ and a mass of M_P_=5.18_-0.22_^+0.21^ M_J_, and from Doppler tomographic observations, we find that the planet's orbit is well-aligned to its host star's projected spin axis ({lambda}=2.6_-3.6_^+5.1^). The young age estimated for KELT-24 suggests that it only recently started to evolve from the zero-age main sequence. KELT-24 is the brightest star known to host a transiting giant planet with a period between 5 and 10 days. Although the circularization timescale is much longer than the age of the system, we do not detect a large eccentricity or significant misalignment that is expected from dynamical migration. The brightness of its host star and its moderate surface gravity make KELT-24b an intriguing target for detailed atmospheric characterization through spectroscopic emission measurements since it would bridge the current literature results that have primarily focused on lower mass hot Jupiters and a few brown dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A39
- Title:
- Radial velocities of GJ 357
- Short Name:
- J/A+A/628/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq=525+/-11K) with a radius of R_b_=1.217+/-0.084R_{Earth}_ and an orbital period of P_b_=3.93d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the existence of the planet and leading to a planetary mass of M_b_=1.84+/-0.31M_{Earth}_. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two more planets in the system: GJ 357 c, with a minimum mass of M_c_=3.40+/-0.46M_{Earth}_ in a 9.12d orbit, and GJ 357 d, with a minimum mass of M_d_=6.1+/-1.0M_{Earth}_ in a 55.7d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot=78+/-2d. GJ 357 b is to date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A171
- Title:
- Radial velocities of GJ 3779 and GJ 1265
- Short Name:
- J/A+A/620/A171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We announce the discovery of two planetary companions orbiting around the low-mass stars Ross 1020 (GJ 3779, M4.0V) and LP 819-052 (GJ 1265, M4.5V). The discovery is based on the analysis of CARMENES radial velocity (RV) observations in the visual channel as part of its survey for exoplanets around M dwarfs. In the case of GJ 1265, CARMENES observations were complemented with publicly available Doppler measurements from HARPS. The datasets reveal two planetary companions, one for each star, that share very similar properties: minimum masses of 8.0+/-0.5M_{Earth}_ and 7.4+/-0.5M_{Earth}_ in low-eccentricity orbits with periods of 3.023+/-0.001d and 3.651+/-0.001d for GJ 3779 b and GJ 1265 b, respectively. The periodic signals around three days found in the RV data have no counterpart in any spectral activity indicator. Furthermore, we collected available photometric data for the two host stars, which confirm that the additional Doppler variations found at periods of approximately 95d can be attributed to the rotation of the stars. The addition of these planets to a mass-period diagram of known planets around M dwarfs suggests a bimodal distribution with a lack of short-period low-mass planets in the range of 2-5M_{Earth}_. It also indicates that super-Earths (>5M_{Earth}_) currently detected by RV and transit techniques around M stars are usually found in systems dominated by a single planet.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A133
- Title:
- Radial velocities of HD215152
- Short Name:
- J/A+A/614/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of four super-earth planets around HD215152, with orbital periods of 5.76, 7.28, 10.86, and 25.2d, and minimum masses of 1.8, 1.7, 2.8, and 2.9M_Earth_ respectively. This discovery is based on 373 high quality radial velocity measurements taken by HARPS over thirteen years. Given the low masses of the planets, the S/N is not sufficient to constrain the planets eccentricities. However, a preliminary dynamical analysis suggests that eccentricities should be typically lower than about 0.03 for the system to remain stable. With two pairs of planets with a period ratio smaller than 1.5, with short orbital periods, small masses, and small eccentricities, HD215152 is similar to the very compact multi-planet systems found by Kepler, and very rare in RV surveys. This discovery proves that those systems are reachable with the RV technique, however they require a huge amount of observations to be characterized.
