- ID:
- ivo://CDS.VizieR/J/AJ/150/169
- Title:
- Radial velocities of HD 6434
- Short Name:
- J/AJ/150/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The current goal of exoplanetary science is not only focused on detecting but characterizing planetary systems in hopes of understanding how they formed, evolved, and relate to the solar system. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) combines both radial velocity (RV) and photometric data in order to achieve unprecedented ground-based precision in the fundamental properties of nearby, bright, exoplanet-hosting systems. Here we discuss HD 6434 and its planet, HD 6434b, which has a M_p_sini=0.44M_J_ mass and orbits every 22.0170 days with an eccentricity of 0.146. We have combined previously published RV data with new measurements to derive a predicted transit duration of ~6 hr, or 0.25 days, and a transit probability of 4%. Additionally, we have photometrically observed the planetary system using both the 0.9 and 1.0m telescopes at the Cerro Tololo Inter-American Observatory, covering 75.4% of the predicted transit window. We reduced the data using the automated TERMS Photometry Pipeline, developed to ensure consistent and accurate results. We determine a dispositive null result for the transit of HD 6434b, excluding the full transit to a depth of 0.9% and grazing transit due to impact parameter limitations to a depth of 1.6%.
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Search Results
- 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/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.
- ID:
- ivo://CDS.VizieR/J/A+A/447/1159
- Title:
- Radial velocities of HD 142022
- Short Name:
- J/A+A/447/1159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report precise Doppler measurements of HD 142022 obtained during the past six years with the CORALIE echelle spectrograph at La Silla Observatory together with a few additional observations made recently with the HARPS echelle spectrograph. Our radial velocities reveal evidence of a planetary companion with an orbital period P=1928^+53^_-39^d, an eccentricity e=0.53^+0.23^_-0.18_, and a velocity semiamplitude K=92^+102^_-29_m/s. The inferred companion minimum mass is M_2_sin{i}=5.1^+2.6^_-1.5_M_Jup_ and the semimajor axis a=3.03+/-0.05AU. Only one full orbital revolution has been monitored yet, and the periastron passage could not be observed since the star was too low on the horizon. The eccentricity and velocity semiamplitude remain therefore quite uncertain and the orbital solution is preliminary. HD 142022 is a chromospherically inactive K0 dwarf, metal rich relative to the Sun, and is the primary component of a wide binary. HD 142022b is thus a new "planet in binary" candidate, and its high eccentricity might be due to secular interactions with the distant stellar companion.
- ID:
- ivo://CDS.VizieR/J/A+A/528/A112
- Title:
- Radial velocities of HD 10180
- Short Name:
- J/A+A/528/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-mass extrasolar planets are presently being discovered at an increased pace by radial velocity and transit surveys, which opens a new window on planetary systems. We are conducting a high-precision radial velocity survey with the HARPS spectrograph, which aims at characterizing the population of ice giants and super-Earths around nearby solar-type stars. This will lead to a better understanding of their formation and evolution, and will yield a global picture of planetary systems from gas giants down to telluric planets. Progress has been possible in this field thanks in particular to the sub-m/s radial velocity precision achieved by HARPS. We present here new high-quality measurements from this instrument. We report the discovery of a planetary system comprising at least five Neptune-like planets with minimum masses ranging from 12 to 25M_{earth}_, orbiting the solar-type star HD 10180 at separations between 0.06 and 1.4AU.
- 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/A+A/480/L33
- Title:
- Radial velocities of HD 4113 and HD 156846
- Short Name:
- J/A+A/480/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of two very eccentric planets orbiting HD 4113 and HD 156846 with the CORALIE Echelle spectrograph mounted on the 1.2-m Euler Swiss telescope at La Silla. The first planet, HD 4113 b, has minimum mass of msini=1.6+/-0.2M_{Jup}_, a period of P=526.59+/-0.21-days and an eccentricity of e=0.903+/-0.02. It orbits a metal rich G5V star at a=1.28AU, which displays an additional radial velocity drift of 28m/s/ observed during 8 years. The second planet, HD 156846 b, has minimum mass of msini=10.45+/-0.05M_{Jup}_, a period of P=359.51+/-0.09days, an eccentricity of e=0.847+/-0.002 and is located at a=1.0AU from its parent star. HD 156846 is a metal rich G0 dwarf and is also the primary of a wide binary system (a>250AU, P>4000-years). Its stellar companion, IDS 17147-1914 B, is a M4 dwarf.
- ID:
- ivo://CDS.VizieR/J/AJ/154/120
- Title:
- Radial velocities of HD 96511, HR 7578, and KZ And
- Short Name:
- J/AJ/154/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From an extensive number of newly acquired radial velocities we determine the orbital elements for three late-type dwarf systems, HD 96511, HR 7578, and KZ And. The orbital periods are 18.89737+/-0.00002, 46.81610+/-0.00006, and 3.0329113+/-0.0000005 days, respectively, and all three systems are eccentric, although KZ And is just barely so. We have detected lines of the secondary of HD 96511 for the first time. The orbital dimensions (a_1_ sin i and a_2_ sin i) and minimum masses (m_1_ sin^3^i and m_2_ sin^3^i) of the binary components all have accuracies of 0.2% or better. Extensive photometry of the chromospherically active binary HR 7578 confirms a rather long rotation period of 16.446+/-0.002 days and that the K3 V components do not eclipse. We have estimated the basic properties of the stars in the three systems and compared those results with evolutionary tracks. The results for KZ And that we computed with the revised Hipparcos parallax of van Leeuwen (Cat. I/311) produce inconsistencies. That parallax appears to be too large, and so, instead, we used the original Hipparcos parallax of the common proper motion primary, which improves the results, although some problems remain.
- ID:
- ivo://CDS.VizieR/J/AJ/124/1118
- Title:
- Radial velocities of high-velocity white dwarfs
- Short Name:
- J/AJ/124/1118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radial velocities and complete space motions were measured for 116 white dwarf stars with M dwarf companions (WD+M), including thirteen pairs having "halo-like" velocities. These 116 WD+dM binaries were observed on the 3.5 m telescope at the Apache Point Observatory (APO) on nearly 30 half-nights between 2000 September 4 and 2001 October 20. The APO Double Imaging Spectrograph was used with a 15" slit, yielding a resolution of approximately 2arcsrc/pixel. From the near-solar abundance levels of the M dwarf companions, only one potential stellar halo white dwarf (LP 164-52) was found in the sample, 12 of the 13 high-velocity white dwarfs being actually part of the high-velocity tail of the thick disk rather than the dark matter halo of the Galaxy.
- 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.
