- ID:
- ivo://CDS.VizieR/J/A+A/529/A134
- Title:
- Velocity curve of {alpha} Arietis
- Short Name:
- J/A+A/529/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To search for extra-solar planets around intermediate mass stars, we are conducting a precise RV survey around K-giants. We present high-accuracy RV measurements of alpha Ari from November 2003 to February 2010. This star belongs to our sample of 55 K-giants studied for extra-solar planet and pulsation searches using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) attached to the 1.8-m telescope at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We find a planetary companion with a long-period and low-amplitude radial velocity (RV) variations in oscillating K2 III star alpha Ari (HD 12929). We do not find the correlation between RV variations and chromospheric activity indicators (CaII H & K region, H{alpha} line). The bisector analysis also shows that bisector velocity span (BVS) does not show any obvious correlation with RV variation but has periodic component that may be attributed to the rotation of the star. If the RV variation is indeed caused by a planetary companion, an orbital solution with a period of P=381-days, a semi-amplitude of K=41m/s, and an eccentricity of e=0.25 fits the data best. Assuming a possible stellar mass of M_star_=1.5M_{sun}_, we estimate the minimum mass for the planetary companion of m_2_sini=1.8M_{Jupiter}_ with an orbital semi-major axis of 1.2AU. Our finding of a likely exoplanet in alpha Ari gives a support to search for extra-solar planets around giant stars with multi-periodic oscillations.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/578/A64
- Title:
- Velocity curve of {tau} Boo A
- Short Name:
- J/A+A/578/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the tau Boo system with the HARPS-N spectrograph in order to test a new observational strategy aimed to jointly study asteroseismology, the planetary orbit and star-planet magnetic interaction. We collected high-cadence observations on 11 nearly consecutive nights, and for each night averaged the raw FITS files using dedicated software in order to obtain high S/N spectra to study the variation of the CaII H&K lines and radial velocity values free from stellar oscillations without losing this latter information. Specific software was written to build a new custom mask used to refine the RV determination with the HARPS-N pipeline and to perform the spectroscopic analysis. We updated the planetary ephemeris and proved the acceleration due to the stellar binary companion. The study of stellar activity variation suggests the presence of an high-latitude plage during the time span of our observations. The correlation between the chromospheric activity and the planetary orbital phase remains unclear. Solar-like oscillations are detected in the radial velocity time series: we estimate asteroseismic quantities finding good agreement with theoretical predictions. With the stellar model built we find for tau Boo an age of 0.9+/-0.5Gyr, and could further constrain the value of the stellar mass to 1.38+/-0.05M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/A+A/566/A67
- Title:
- Velocity curves of {beta}Cnc, {mu}Leo and {beta}UMi
- Short Name:
- J/A+A/566/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To investigate the low-amplitude and long-period variations in evolved stars with a precise radial velocity (RV) survey. The high-resolution, the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) was used from 2003 to 2013 for an RV survey of giant stars as part of the exoplanet search program at Bohyunsan Optical Astronomy Observatory (BOAO). We report the detection of three new planetary companions orbiting the K giants beta Cnc, mu Leo, and beta UMi. The planetary nature of the RV variations is supported by analyses of ancillary data. The HIPPARCOS photometry shows no variations with periods close to those in RV variations and there is no strong correlation between the bisector velocity span (BVS) and the RVs for each star. Furthermore, the stars show weak or no core reversal in Ca II H lines indicating that they are inactive stars. The companion to beta Cnc has a minimum mass of 7.8M_Jup_ in a 605-day orbit with an eccentricity of 0.08. mu Leo is orbited by a companion of minimum mass of 2.4M_Jup_ having a period of 357-days, and an eccentricity of 0.09. beta UMi is a known barium star and is suspected of harbouring a white dwarf or substellar mass companion. Its companion has a minimum mass of 6.1M_Jup_, a period of 522-days, and an eccentricity e=0.19.
- ID:
- ivo://CDS.VizieR/J/A+A/493/639
- Title:
- Velocity curves of HD 40307
- Short Name:
- J/A+A/493/639
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a planetary system with three Super-Earths orbiting HD 40307. HD 40307 is a K2 V metal-deficient star at a distance of only 13 parsec, which is part of the HARPS GTO high-precision planet-search programme. The three planets on circular orbits have very low minimum masses of 4.2, 6.9, and 9.2 Earth masses and periods of 4.3, 9.6, and 20.5 days, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A59
- Title:
- Velocity monitoring for 3 stars with HARPS
- Short Name:
- J/A+A/551/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of 850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD 103774, HD 109271, and BD-061339. In this work we present the detection of five planets orbiting these stars, with msini between 0.6 and 7 Neptune masses, four of which are in two multiple systems, comprising one super-Earth and one planet within the habitable zone of a late-type dwarf. Although for strategic reasons we chose efficiency over precision in this survey, we have the capability to detect planets down to the Neptune and super-Earth mass range as well as multiple systems, provided that enough data points are made available.
- ID:
- ivo://CDS.VizieR/J/A+A/526/A141
- Title:
- Velocity monitoring of Gl 676A and HIP 12961
- Short Name:
- J/A+A/526/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fewer giants planets are found around M dwarfs than around more massive stars, and this dependence of planetary characteristics on the mass of the central star is an important observational diagnostic of planetary formation theories. In part to improve on those statistics, we are monitoring the radial velocities of nearby M dwarfs with the HARPS spectrograph on the ESO 3.6m telescope. We present here the detection of giant planets around two nearby M0 dwarfs: planets, with minimum masses of respectively 5 Jupiter masses and 1 Saturn mass, orbit around Gl 676A and HIP 12961.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A53
- Title:
- Venus mesosphere ALMA observations
- Short Name:
- J/A+A/606/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Water vapor and sulfur compounds are key species in the photochemistry of Venus mesosphere. These species, together with mesospheric temperatures, exhibit drastic temporal variations, both on short timescales (diurnal and day-to-day) as well on long timescales, far from being understood. We targeted CO, SO, H_2_O and SO_2_ transitions in the submillimeter range using the Atacama Large Millimeter Array (ALMA) to study their spatial and temporal variations. Four sets of observations were acquired on different dates in November 2011 during the first ALMA Early Science observation Cycle 0. Venus angular diameter was about 11" with an illumination factor of 92%, so that mostly the day side of the planet was mapped. Assuming a nominal CO abundance profile, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time. Temperature profiles were later used to retrieve SO, SO_2_, and H_2_O. We used H_2_O as a tracer for water assuming a D/H enrichment of 200 times the terrestrial value. We derived 3-D maps of mesospheric temperatures in the altitude range 70-105km. SO, SO_2_, and H_2_O are characterized by a negligible abundance below ~85km followed by an increase with altitude in the upper mesosphere. Disk-averaged SO abundances present a maximum mixing ratio of 15.0+/-3.1ppb on November 26 followed the next day by a minimum value of 9.9+/-1.2ppb. Due to a very low S/N, SO_2_ could only be derived from the disk-averaged spectrum on the first day of observation revealing an abundance of 16.5+/-4.6ppb. We found a SO_2_/SO ratio of 1.5+/-0.4. Global maps of SO reveal strong variations both with latitude and local time and from day to day with abundance ranging from <1 to 15ppb. H_2_O disk-averages retrievals reveal a steady decrease from November 14 to 27, with the abundance varying from 3.6+/-0.6ppm on the first day to 2.9+/-0.7ppm on the last day. H_2_O maps reveal a slightly higher abundance on the evening side compared to the morning side and a strong depletion between the first and the second day of observation.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A82
- Title:
- Venus photometric flux and los velocities
- Short Name:
- J/A+A/627/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measuring Venus' atmospheric circulation at different altitudes is important for understanding its complex dynamics, in particular the mechanisms driving the super-rotation. Observationally, Doppler imaging spectroscopy is in principle be the most reliable way to measure wind speeds of planetary atmospheres because it directly provides the projected speed of atmospheric particles. However, high-resolution imaging-spectroscopy is challenging, especially in the visible domain, and most of the knowledge about atmospheric dynamics has been obtained with cloud-tracking technique. The objective of the present work is to measure the global properties of Venus' atmospheric dynamics at the altitude of the uppermost clouds, which is probed by reflected solar lines in the visible domain. Our results are based on high-resolution spectroscopic observations with the long slit spectrometer of the solar telescope THEMIS. We present the first instantaneous "radial-velocity snapshot" of any planet of the solar system in the visible domain, i.e., a complete RV map of the planet obtained by stacking data on less than 10% of its rotation period. From this, we measure the properties of the zonal and meridional winds, which we unambiguously detect. We identify a wind circulation pattern that significantly differs from previous knowledge about Venus. The zonal wind displays a "hot spot" structure, featuring about 200m/s at sunrise and 70m/s at noon in the equatorial region. Regarding meridional winds, we detect an equator-to-pole meridional flow peaking at 45m/s at mid latitudes, i.e., which is about twice as large as what was reported so far.
- ID:
- ivo://CDS.VizieR/J/A+A/572/A49
- Title:
- WASP-94AB photometry and radial velocities
- Short Name:
- J/A+A/572/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two hot-Jupiter planets, one orbiting each star of a wide binary system. WASP-94A (2MASS 20550794-3408079) is an F8 type star hosting a transiting planet with a radius of 1.72+/-0.06R_Jup_, a mass of 0.445+/ 0.026M_Jup_ and an orbital period of 3.95 days. The Rossiter-McLaughlin effect is clearly detected and the measured projected spin-orbit angle indicates that the planet occupies a retrograde orbit. WASP-94B (2MASS 20550915-3408078) is an F9 stellar companion at an angular separation of 15" (projected separation 2700AU), hosting a gas giant of minimum mass 0.617+/-0.028M_Jup_ with a period of 2.008-days, detected by Doppler measurements. The orbital planes of the two planets are inclined relative to each other, indicating that at least one of them is inclined relative to the plane of the stellar binary. These hot Jupiters in a binary system bring new insights into the formation of close-in giant planets and the role of stellar multiplicity.
- ID:
- ivo://CDS.VizieR/J/A+A/599/A3
- Title:
- WASP 127, 136 and 138 RV and light curves
- Short Name:
- J/A+A/599/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report three newly discovered exoplanets from the SuperWASP survey. WASP-127b is a heavily inflated super-Neptune of mass 0.18+/-0.02 M_J_ and radius 1.37+/-0.04 R_J_. This is one of the least massive planets discovered by the WASP project. It orbits a bright host star (Vmag=10.16) of spectral type G5 with a period of 4.17 days. WASP-127b is a low-density planet that has an extended atmosphere with a scale height of 2500+/-400km, making it an ideal candidate for transmission spectroscopy. WASP-136b and WASP-138b are both hot Jupiters with mass and radii of 1.51+/-0.08M_J_ and 1.38+/-0.16R_J_, and 1.22+/-0.08M_J_ and 1.09+/-0.05R_J_, respectively. WASP-136b is in a 5.22-day orbit around an F9 subgiant star with a mass of 1.41+/-0.07M_{sun}_ and a radius of 2.21+/-0.22R_{sun}_. The discovery of WASP-136b could help constrain the characteristics of the giant planet population around evolved stars. WASP-138b orbits an F7 star with a period of 3.63 days. Its radius agrees with theoretical values from standard models, suggesting the presence of a heavy element core with a mass of ~10M_{earth}_. The discovery of these new planets helps in exploring the diverse compositional range of short-period planets, and will aid our understanding of the physical characteristics of both gas giants and low-density planets.
