- ID:
- ivo://CDS.VizieR/J/A+A/613/A47
- Title:
- Radial velocities of 12 evolved stars
- Short Name:
- J/A+A/613/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocities and line bisectors for 12 giants with high Li abundance. We report the discovery of two new planetary systems around HD238914 and TYC3318-01333-1, reveal a binary Li-rich giant HD181368. Although our current phase coverage is not complete, we suggest the presence of planetary mass companions around TYC3663-01966-1 and TYC3105-00152-1. We confirm the previous result for BD+48 740 (Adamow et al, 2012ApJ...754L..15A).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/727/117
- Title:
- Radial velocities of four exoplanet candidates
- Short Name:
- J/ApJ/727/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new precise HIRES radial velocity (RV) data sets of five nearby stars obtained at Keck Observatory. HD 31253, HD 218566, HD 177830, HD 99492, and HD 74156 are host stars of spectral classes F through K and show RV variations consistent with new or additional planetary companions in Keplerian motion. The orbital parameters of the candidate planets in the five planetary systems span minimum masses of Msini=27.43M_{sun}_ to 8.28M_J_, periods of 17.05-4696.95 days and eccentricities ranging from circular to extremely eccentric (e~0.63). The fifth star, HD 74156, was known to have both a 52 day and a 2500 day planet, and was claimed to also harbor a third planet at 336 days, in apparent support of the "Packed Planetary System" hypothesis. Our greatly expanded data set for HD 74156 provides strong confirmation of both the 52 day and 2500 day planets, but strongly contradicts the existence of a 336 day planet, and offers no significant evidence for any other planets in the system.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A112
- Title:
- Radial velocities of HARPS metal-poor sample
- Short Name:
- J/A+A/526/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Searching for extrasolar planets around stars of different metallicity may provide strong constraints to the models of planet formation and evolution. In this paper we present the overall results of a HARPS (a high-precision spectrograph mostly dedicated to deriving precise radial velocities) program to search for planets orbiting a sample of 104 metal-poor stars (selected [Fe/H] below -0.5). Radial velocity time series of each star are presented and searched for signals using several statistical diagnostics. tars with detected signals are presented, including 3 attributed to the presence of previously announced giant planets orbiting the stars HD171028, HD181720, and HD190984. Several binary stars and at least one case of a coherent signal caused by activity-related phenomena are presented. One very promising new, possible giant planet orbiting the star HD107094 is discussed, and the results are analyzed in light of the metallicity-giant planet correlation. We conclude that the frequency of giant planets orbiting metal-poor stars may be higher than previously thought, probably reflecting the higher precision of the HARPS survey. In the metallicity domain of our sample, we also find evidence that the frequency of planets is a steeply rising function of the stellar metal content, as found for higher metallicity stars.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A35
- Title:
- Radial velocities of HD 41248
- Short Name:
- J/A+A/566/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The search for planets orbiting metal-poor stars is of uttermost importance for our understanding of the planet formation models. However, no dedicated searches have been conducted so far for very low mass planets orbiting such objects. Only a few cases of low mass planets orbiting metal-poor stars are thus known. Amongst these, HD 41248 is a metal-poor, solar-type star on which a resonant pair of super-Earth like planets has been announced. This detection was based on 62 radial velocity measurements obtained with the HARPS spectrograph (public data). In the present paper we present a new planet search program that is using the HARPS spectrograph to search for Neptunes and Super-Earths orbiting a sample of metal-poor FGK dwarfs. We then present a detailed analysis of an additional 162 radial velocity measurements of HD 41248, obtained within this program, with the goal of confirming the existence of the proposed planetary system. We analyzed the precise radial velocities, obtained with the HARPS spectrograph, together with several stellar activity diagnostics and line profile indicators. A careful analysis shows no evidence for the planetary system previously announced. One of the signals, with a period of ~25 days, is shown to be related to the rotational period of the star, and is clearly seen in some of the activity proxies. The remaining signal (P~18 days) could not be convincingly retrieved in the new data set. We discuss possible causes for the complex (evolving) signals observed in the data of HD 41248, proposing that they may be explained by the appearance and disappearance of active regions on the surface of a star with strong differential rotation, or by a combination of the sparse data sampling and active region evolution.
- ID:
- ivo://CDS.VizieR/J/AJ/152/167
- Title:
- Radial velocities of HD 133131A and HD 133131B
- Short Name:
- J/AJ/152/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new precision radial velocity (RV) data set that reveals multiple planets orbiting the stars in the ~360 au, G2+G2 "twin" binary HD133131AB. Our six years of high-resolution echelle observations from MIKE and five years from the Planet Finder Spectrograph (PFS) on the Magellan telescopes indicate the presence of two eccentric planets around HD133131A with minimum masses of 1.43+/-0.03 and 0.63+/-0.15M_J_ at 1.44+/-0.005 and 4.79+/-0.92au, respectively. Additional PFS observations of HD133131B spanning five years indicate the presence of one eccentric planet of minimum mass 2.50+/-0.05M_J_ at 6.40+/-0.59au, making it one of the longest-period planets detected with RV to date. These planets are the first to be reported primarily based on data taken with the PFS on Magellan, demonstrating the instrument's precision and the advantage of long-baseline RV observations. We perform a differential analysis between the Sun and each star, and between the stars themselves, to derive stellar parameters and measure a suite of 21 abundances across a wide range of condensation temperatures. The host stars are old (likely ~9.5Gyr) and metal-poor ([Fe/H]~-0.30), and we detect a ~0.03dex depletion in refractory elements in HD133131A versus B (with standard errors ~0.017). This detection and analysis adds to a small but growing sample of binary "twin" exoplanet host stars with precise abundances measured, and represents the most metal-poor and likely oldest in that sample. Overall, the planets around HD133131A and B fall in an unexpected regime in planet mass-host star metallicity space and will serve as an important benchmark for the study of long-period giant planets.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/L33
- Title:
- Radial velocities of 2 hot Jupiters in Praesepe
- Short Name:
- J/ApJ/756/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two giant planets orbiting stars in Praesepe (also known as the Beehive Cluster). These are the first known hot Jupiters in an open cluster and the only planets known to orbit Sun-like, main-sequence stars in a cluster. The planets are detected from Doppler-shifted radial velocities; line bisector spans and activity indices show no correlation with orbital phase, confirming the variations are caused by planetary companions. Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264+/-0.0070 days and has a minimum mass of 0.540+/-0.039M_Jup_, and Pr0211b orbits a V=12.06 late G dwarf with a period of 2.1451+/-0.0012 days and has a minimum mass of 1.844+/-0.064M_Jup_. The detection of two planets among 53 single members surveyed establishes a lower limit of 3.8^+5.0^_-2.4_% on the hot Jupiter frequency in this metal-rich open cluster. Given the precisely known age of the cluster, this discovery also demonstrates that, in at least two cases, giant planet migration occurred within 600Myr after formation. As we endeavor to learn more about the frequency and formation history of planets, environments with well-determined properties--such as open clusters like Praesepe--may provide essential clues to this end.
- ID:
- ivo://CDS.VizieR/J/ApJ/654/625
- Title:
- Radial velocities of 9 long-period objects
- Short Name:
- J/ApJ/654/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The possible existence of additional long-period planetary-mass objects in the extrasolar planetary systems 47 UMa and 14 Her is investigated. We combine all available radial velocity data on these stars, spanning up to 18yr. For the 47 UMa system, we show that while a second planet improves the fit to all available data, there is still substantial ambiguity as to the orbital parameters of the proposed planetary companion 47 UMa c. We also present new observations that clearly support a long-period companion in the 14 Her system. With a period of 6906+/-70 days, 14 Her c may be in a 4:1 resonance with the inner planet. We also present revised orbital solutions for seven previously known planets, incorporating recent additional data obtained with the 2.7m Harlan J. Smith Telescope at McDonald Observatory.
- ID:
- ivo://CDS.VizieR/J/ApJ/800/22
- Title:
- Radial velocities of long-period planets
- Short Name:
- J/ApJ/800/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an update to seven stars with long-period planets or planetary candidates using new and archival radial velocities from Keck-HIRES and literature velocities from other telescopes. Our updated analysis better constrains orbital parameters for these planets, four of which are known multi-planet systems. HD24040b and HD183263c are super-Jupiters with circular orbits and periods longer than 8yr. We present a previously unseen linear trend in the residuals of HD 66428 indicative of an additional planetary companion. We confirm that GJ 849 is a multi-planet system and find a good orbital solution for the c component: it is a 1M_Jup_ planet in a 15yr orbit (the longest known for a planet orbiting an M dwarf). We update the HD74156 double-planet system. We also announce the detection of HD145934b, a 2M_Jup_ planet in a 7.5yr orbit around a giant star. Two of our stars, HD187123 and HD217107, at present host the only known examples of systems comprising a hot Jupiter and a planet with a well constrained period greater than 5yr, and with no evidence of giant planets in between. Our enlargement and improvement of long-period planet parameters will aid future analysis of origins, diversity, and evolution of planetary systems.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/97
- Title:
- Radial velocities of multi-planet systems
- Short Name:
- J/ApJS/182/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extrasolar multiple-planet systems provide valuable opportunities for testing theories of planet formation and evolution. The architectures of the known multiple-planet systems demonstrate a fascinating level of diversity, which motivates the search for additional examples of such systems in order to better constrain their formation and dynamical histories. Here we describe a comprehensive investigation of 22 planetary systems in an effort to answer three questions: (1) are there additional planets? (2) where could additional planets reside in stable orbits? and (3) what limits can these observations place on such objects? We find no evidence for additional bodies in any of these systems; indeed, these new data do not support three previously announced planets (HD 20367 b: Udry et al., 2003ASPCC..294...17U; HD 74156 d: Bean et al., 2008ApJ...672.1202B; and 47 UMa c: Fischer et al., 2002ApJ...564.1028F). The dynamical simulations show that nearly all of the 22 systems have large regions in which additional planets could exist in stable orbits. The detection-limit computations indicate that this study is sensitive to close-in Neptune-mass planets for most of the systems targeted. We conclude with a discussion on the implications of these nondetections.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/46
- Title:
- Radial velocities of 3 Neptune-mass planet hosts
- Short Name:
- J/ApJ/830/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD42618b has a minimum mass of 15.4+/-2.4 M_{Earth}_, a semimajor axis of 0.55au, an equilibrium temperature of 337K, and is the first planet discovered to orbit the solar analogue host star, HD42618. We also discover new planets orbiting the known exoplanet host stars HD164922 and HD143761 ({rho} CrB). The new planet orbiting HD164922 has a minimum mass of 12.9+/-1.6 M_{Earth}_ and orbits interior to the previously known Jovian mass planet orbiting at 2.1au. HD164922c has a semimajor axis of 0.34au and an equilibrium temperature of 418K. HD143761c orbits with a semimajor axis of 0.44au, has a minimum mass of 25+/-2 M_{Earth}_, and is the warmest of the three new planets with an equilibrium temperature of 445K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets.
