- ID:
- ivo://CDS.VizieR/J/A+A/619/A2
- Title:
- Velocity curves of 3 open cluster stars
- Short Name:
- J/A+A/619/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this work is to search for planets around intermediate-mass stars in open clusters by using data from an extensive survey with more than 15 years of observations. We obtain high-precision radial velocities (RV) with the HARPS spectrograph for a sample of 142 giant stars in 17 open clusters. We fit Keplerian orbits when a significant periodic signal is detected. We also study the variation of stellar activity indicators and line-profile variations to discard stellar-induced signals. We present the discovery of a periodic RV signal compatible with the presence of a planet candidate in the 1.15Gyr open cluster IC4651 orbiting the 2.06M_{sun}_ star No. 9122. If confirmed, the planet candidate would have a minimum mass of 7.2M_J_ and a period of 747 days. However, we also find that the FWHM of the CCF varies with a period close to the RV, casting doubts on the planetary nature of the signal. We also provide refined parameters for the previously discovered planet around NGC2423 No. 3 but show evidence that the BIS of the CCF is correlated with the RV during some of the observing periods. This fact advises us that this might not be a real planet and that the RV variations could be caused by stellar activity and/or pulsations. Finally, we show that the previously reported signal by a brown dwarf around NGC4349 No. 127 is presumably produced by stellar activity modulation. The long-term monitoring of several red giants in open clusters has allowed us to find periodic RV variations in several stars. However, we also show that the follow-up of this kind of stars should last more than one orbital period to detect long-term signals of stellar origin. This work warns that although it is possible to detect planets around red giants, large-amplitude, long-period RV modulations do exist in such stars that can mimic the presence of an orbiting planetary body. Therefore, we need to better understand how such RV modulations behave as stars evolve along the Red Giant Branch and perform a detailed study of all the possible stellar-induced signals (e.g. spots, pulsations, granulation) to comprehend the origin of RV variations.
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Search Results
- 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/ApJ/889/176
- Title:
- Very low-mass binaries with Gaia DR2 data
- Short Name:
- J/ApJ/889/176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of WISE 2150-7520AB (W2150AB): a widely separated (~341au) very low-mass L1+T8 co-moving system. The system consists of the previously known L1 primary 2MASS J21501592-7520367 and a newly discovered T8 secondary found at position 21:50:18.99-75:20:54.6 (MJD=57947) using Wide-field Infrared Survey Explorer data via the Backyard Worlds: Planet 9 citizen science project. We present Spitzer ch1 and ch2 photometry (ch1-ch2=1.41+/-0.04mag) of the secondary and Folded-port InfraRed Echellette prism spectra of both components. The sources show no peculiar spectral or photometric signatures, indicating that each component is likely field age. Using all observed data and the Gaia DR2 parallax of 41.3593+/-0.2799mas for W2150A we deduce fundamental parameters of log(L_bol_/L_{sun}_)=-3.69+/-0.01, Teff=2118+/-62K, and an estimated mass=72+/-12M_Jup_ for the L1 and log(L_bol_/L_{sun}_)=-5.64+/-0.02, Teff=719+/-61K, and an estimated mass=34+/-22M_Jup_ for the T8. At a physical separation of ~341au this system has E_bin_=10^41^erg, making it the lowest binding energy system of any pair with M_tot_<0.1M_{sun}_ not associated with a young cluster. It is equivalent in estimated mass ratio, E_bin_, and physical separation to the ~2Myr M7.25+M8.25 binary brown dwarf 2MASS J11011926-7732383AB (2M1101AB) found in the Chameleon star-forming region. W2150AB is the widest companion system yet observed in the field where the primary is an L dwarf or later.
- ID:
- ivo://CDS.VizieR/J/A+A/364/665
- Title:
- Very low mass stars radial velocities
- Short Name:
- J/A+A/364/665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained adaptive optics images and accurate radial velocities for 7 very low mass objects, In the course of a long term effort to determine accurate masses for very low mass stars (M<0.6 M{sun}). We use the new data, together with measurements from the literature for some stars, to determine new or improved orbits for these 7 systems. They provide masses for 16 very low mass stars with accuracies that range between 0.2% and 5%, and in some cases a very accurate distance as well. This information is used in a companion paper to discuss the Mass-Luminosity relation for the V, J, H and K photometric bands.
- ID:
- ivo://CDS.VizieR/J/AJ/134/2272
- Title:
- Visual binaries in the Orion Nebula Cluster
- Short Name:
- J/AJ/134/2272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a major survey for visual binaries toward the Orion Nebula Cluster, using images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope through an Halpha filter. From 1051 stars more than 60" from theta^1^ Ori C, we have selected 781 that fulfill the criteria for membership in the Orion Nebula Cluster. Among these, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". We perform a statistical study of the 72 binaries and 3 triples that have separations in the limited range 0.15" to 1.5", within which we need no incompleteness correction.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A98
- Title:
- VIsual Binary Exoplanet survey with SPHERE
- Short Name:
- J/A+A/643/A98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent surveys indicate that planets in binary systems are more abunda- nt than previously thought, which is in agreement with theoretical work on disc dynamics and planet formation in binaries. So far, most observational surveys, however, have focused on short-period planets in binaries, thus little is known about the occurrence rates of planets on longer periods (>10au). In order to measure the abundance and physical characteristics of wide-orbit giant exoplanets in binary systems, we have designed the 'VIsual Binary Exoplanet survey with Sphere' (VIBES) to search for planets in visual binaries. It uses the SPHERE instrument at VLT to search for planets in 23 visual binary and four visual triple systems with ages of <145Myr and distances of <150pc. We used the IRDIS dual-band imager on SPHERE to acquire high-contrast images of the sample targets. For each binary, the two components were observed at the same time with a coronagraph masking only the primary star. For the triple star, the tight components were treated as a single star for data reduction. This enabled us to effectively search for companions around 50 individual stars in binaries and four binaries in triples. We derived upper limits of <13.7% for the frequency of sub-stellar companions around primaries in visual binaries, <26.5% for the fraction of sub-stellar companions around secondaries in visual binaries, and an occurrence rate of <9.0% for giant planets and brown dwarfs around either component of visual binaries. We have combined our observations with literature measurements to astrometrically confirm, for the first time, that 20 binaries and two triple systems, which were previously known, are indeed physically bound. Finally, we discovered a third component of the binary HD 121336. The upper limits we derived are compatible with planet formation through the core accretion and the gravitational instability processes in binaries. These limits are also in line with limits found for single star and circumbinary planet search surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/341/121
- Title:
- Visual binary orbits and masses
- Short Name:
- J/A+A/341/121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper gives orbits and masses for some 200 nearby visual binaries, as derived from combining ground-based and Hipparcos data. Table 6 gives identifications and notes, and points to the detailed data in Table 1 (short-P systems with mass-ratio from the Hipparcos observations), Table 3 (mass-uncertainty below 10%) or Table 4 (mass-uncertainty above 10%).
- ID:
- ivo://CDS.VizieR/J/PAZh/24/307
- Title:
- Visual components in 82 multiple systems
- Short Name:
- J/PAZh/24/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a BVR photometry observations are presented for multiple stars visual subsystems (table2.dat). The objects (table1.dat) were observed in 1996 with the 60 cm and 1 m telescopes at Maidanak Observatory (Uzbekistan) by aperture and scanning photometers. The positional parameters and physical relation of visual subsystems are also given (table4.dat).
- ID:
- ivo://CDS.VizieR/I/260
- Title:
- Visual Double Stars in Hipparcos
- Short Name:
- I/260
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue is the only complete list of all known double and multiple systems (18644) of which at least one component was identified in the Hipparcos final catalog in July 1997 (Cat. <I/239>), including the 2994 systems newly discovered by the satellite, as well as the 155 new astrometric orbital pairs also discovered by the satellite (Dommanget, 2000Obs...120..202D), and also the 38 new astrometric binaries components of known systems. It may be considered as a subset of the CCDM as existing in 1998 of which a first edition appeared in 1994 (Cat. <I/211>), and of which a second edition containing more than 45,000 systems is being prepared for publication. Consequently, the format of this list is that of the CCDM for which all information may be found in the introduction of its 1994 published version (as file I/211/ccdm.doc) The format of this catalogue is the same as the CCDM (Cat. <I/211>)
