- ID:
- ivo://CDS.VizieR/J/A+A/465/257
- Title:
- Radial velocity in multiple systems
- Short Name:
- J/A+A/465/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We want to improve the knowledge of orbits, physical parameters and statistics of nearby multiple systems. Radial velocities were measured with a correlation spectrometer during 2001-2006 to determine or improve spectroscopic orbits of the components of some visual multiple systems. We compile all available observational data and estimate masses and orbital periods in these hierarchical multiple systems. Masses and ages of evolved components are derived by fitting isochrones. Three new spectroscopic orbits of close sub-systems (HD 52452B, 157358Aab, 219877B) are determined and one more orbit (HD 139461) is improved. The composite-spectrum system HD 157358Aab was resolved by speckle-interferometry; its preliminary combined orbit is computed to guide future interferometric observations.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/374/227
- Title:
- Radial velocity in multiple systems
- Short Name:
- J/A+A/374/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New close sub-systems are reported and studied in eight visual multiple systems. Elements of one double-lined and eight single-lined spectroscopic orbits are given. Magnitudes, colors, spectral types, masses of individual components are estimated by combining all available data. The visual secondary component of the young binary HD 27638 is a double-lined pair of G-type dwarfs on a 17-day orbit with an unseen but massive (>1.2M_{sun}_) spectroscopic tertiary on an 8-year orbit. The invisible secondary of HD 28271A is also massive, but it is not seen probably owing to a high luminosity of the primary - an F7 star with fast axial rotation and active chromosphere which evolves off the Main Sequence. Two additional companions are found in the visual triple system HD 179484.
- ID:
- ivo://CDS.VizieR/J/AJ/159/235
- Title:
- Radial Velocity jitters in ~600 planet host stars
- Short Name:
- J/AJ/159/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radial velocity (RV) detection of planets is hampered by astrophysical processes on the surfaces of stars that induce a stochastic signal, or "jitter," which can drown out or even mimic planetary signals. Here, we empirically and carefully measure the RV jitter of more than 600 stars from the California Planet Search sample on a star by star basis. As part of this process, we explore the activity-RV correlation of stellar cycles and include appendices listing every ostensibly companion-induced signal we removed and every activity cycle we noted. We then use precise stellar properties from Brewer+, 2017ApJS..230...12B to separate the sample into bins of stellar mass and examine trends with activity and with evolutionary state. We find that RV jitter tracks stellar evolution and that in general, stars evolve through different stages of RV jitter: the jitter in younger stars is driven by magnetic activity, while the jitter in older stars is convectively driven and dominated by granulation and oscillations. We identify the "jitter minimum"-where activity-driven and convectively driven jitter have similar amplitudes-for stars between 0.7 and 1.7M{sun} and find that more-massive stars reach this jitter minimum later in their lifetime, in the subgiant or even giant phases. Finally, we comment on how these results can inform future RV efforts, from prioritization of follow-up targets from transit surveys like the Transiting Exoplanet Survey Satellite (TESS) to target selection of future RV surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A71
- Title:
- Radial velocity measurements for 7 stars
- Short Name:
- J/A+A/625/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Since 1998, a planet-search around main sequence stars within 50pc in the southern hemisphere has been underway with the CORALIE spectrograph at La Silla Observatory. With an observing time span of more than 20 years, the CORALIE survey is able to detect long-term trends in data with masses and separations large enough to select ideal targets for direct imaging. Detecting these giant companion candidates will allow us to start bridging the gap between radial-velocity-detected exoplanets and directly imaged planets and brown dwarfs. Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of massive planetary companions and brown dwarfs on long-period orbits. In this paper we report the discovery of new companions orbiting HD 181234, HD 13724, HD 25015, HD 92987 and HD 50499. We also report updated orbital parameters for HD 50499b, HD 92788b and HD 98649b. In addition, we confirm the recent detection of HD 92788c. The newly reported companions span a period range of 15.6 to 40.4 years and a mass domain of 2.93 to 26.77 MJup, the latter of which straddles the nominal boundary between planets and brown dwarfs. We report the detection of five new companions and updated parameters of four known extrasolar planets. We identify at least some of these companions to be promising candidates for imaging and further characterisation.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/27
- Title:
- Radial velocity measurements in LAMOST-II
- Short Name:
- J/ApJS/244/27
- Date:
- 09 Dec 2021
- Publisher:
- CDS
- Description:
- The radial velocity (RV) is a basic physical quantity that can be determined through the Doppler shift of the spectrum of a star. The precision of the RV measurement depends on the resolution of the spectrum we used and the accuracy of wavelength calibration. In this work, radial velocities of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope-II (LAMOST-II) medium-resolution (R~7500) spectra are measured for 1,594,956 spectra (each spectrum has two wavebands) through matching with templates. A set of RV standard stars are used to recalibrate the zero point of the measurement, and some reference sets with RVs derived from medium-/high-resolution observations are used to evaluate the accuracy of the measurement. By comparing with reference sets, the accuracy of our measurement can get 0.0277km/s with respect to radial velocities of standard stars. The intrinsic precision is estimated with the multiple observations of single stars, which can be achieved to 1.36km/s, 1.08km/s, and 0.91km/s for the spectra at signal-to-noise levels of 10, 20, and 50, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/507/1659
- Title:
- Radial velocity measurements of 30 Ari B
- Short Name:
- J/A+A/507/1659
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Most current radial velocity planet search programs have concentrated on stars of one solar mass. Our knowledge on the frequency of giant planets and brown dwarf companions to more massive stars is thus rather limited. In the case of solar-like stars, the frequency of short-period brown dwarf companions and very massive planets seems to be low. Aims. Here we present evidence for a substellar companion to 30 Ari B, an F-star of 1.16+/-0.04M_{sun}_ that is a member of a hierarchical triple system. The companion was detected by means of precise radial velocity measurements using the 2-m Alfred-Jensch telescope and its echelle spectrograph. An iodine absorption cell provided the wavelength reference for precise stellar radial velocity measurements.
- ID:
- ivo://CDS.VizieR/J/ApJ/860/1
- Title:
- Radial velocity measurements of 20 EBs in LMC
- Short Name:
- J/ApJ/860/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a determination of the precise fundamental physical parameters of 20 detached, double-lined, eclipsing binary stars in the Large Magellanic Cloud (LMC) containing G- or early K-type giant stars. Eleven are new systems; the remaining nine are systems already analyzed by our team for which we present updated parameters. The catalog results from our long-term survey of eclipsing binaries in the Magellanic Clouds suitable for high-precision determination of distances (the Araucaria Project). The V-band brightnesses of the systems range from 15.4 to 17.7mag, and their orbital periods range from 49 to 773days. Six systems have favorable geometry showing total eclipses. The absolute dimensions of all eclipsing binary components are calculated with a precision of better than 3%, and all systems are suitable for a precise distance determination. The measured stellar masses are in the range 1.4 to 4.6M_{sun}_, and comparison with the MESA isochrones gives ages between 0.1 and 2.1Gyr. The systems show an age-metallicity relation with no evolution of metallicity for systems older than 0.6Gyr, followed by a rise to a metallicity maximum at age 0.5Gyr and then a slow metallicity decrease until 0.1Gyr. Two systems have components with very different masses: OGLE LMC-ECL-05430 and OGLE LMC-ECL-18365. Neither system can be fitted by a single stellar evolution isochrone, explained by a past mass transfer scenario in the case of ECL-18365 and a gravitational capture or hierarchical binary merger scenario in the case of ECL-05430. The longest-period system, OGLE LMC SC9_230659, shows a surprising apsidal motion that shifts the apparent position of the eclipses. This is a clear sign of a physical companion to the system; however, neither investigation of the spectra nor light-curve analysis indicates a third-light contribution larger than 2%-3%. In one spectrum of OGLE LMC-ECL-12669, we noted a peculiar dimming of one of the components by 65% well outside of the eclipses. We interpret this observation as arising from an extremely rare occultation event, as a foreground Galactic object covers only one component of an extragalactic eclipsing binary.
- ID:
- ivo://CDS.VizieR/J/AJ/157/97
- Title:
- Radial velocity measurements of K2-3 & GJ3470
- Short Name:
- J/AJ/157/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report improved masses, radii, and densities for four planets in two bright M-dwarf systems, K2-3 and GJ3470, derived from a combination of new radial velocity and transit observations. Supplementing K2 photometry with follow-up Spitzer transit observations refined the transit ephemerides of K2-3 b, c, and d by over a factor of 10. We analyze ground-based photometry from the Evryscope and Fairborn Observatory to determine the characteristic stellar activity timescales for our Gaussian Process fit, including the stellar rotation period and activity region decay timescale. The stellar rotation signals for both stars are evident in the radial velocity data and is included in our fit using a Gaussian process trained on the photometry. We find the masses of K2-3 b, K2-3 c, and GJ3470 b to be 6.48_-0.93_^+0.99^, 2.14_-1.04_^+1.08^, and 12.58_-1.28_^+1.31^ M_{Earth}_, respectively. K2-3 d was not significantly detected and has a 3{sigma} upper limit of 2.80 M_{Earth}_. These two systems are training cases for future TESS systems; due to the low planet densities ({rho}<3.7 g/cm^-3^) and bright host stars (K<9 mag), they are among the best candidates for transmission spectroscopy in order to characterize the atmospheric compositions of small planets.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A159
- Title:
- Radial velocity measurements of 51 Peg
- Short Name:
- J/A+A/646/A159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The analysis of exoplanetary atmospheres by means of high-resolution spectroscopy is an expanding research field which provides information o n chemical composition, thermal structure, atmospheric dynamics and orbital velocity of exoplanets. In this work, we aim at the detection of the light reflected by the exoplanet 51 Peg b employing optical high-resolution spectroscopy. To detect the light reflected by the planetary dayside we use optical HARPS and HARPS-N spectra taken near the superior conjunction of the planet, when the flux contrast between the planet and the star is maximum. To search for the weak planetary signal, we cross-correlate the observed spectra with a high S/N stellar spectrum. We homogeneously analyze the available datasets and derive a 10^-5^ upper limit on the planet-to-star flux contrast in the optical. The upper limit on the planet-to-star flux contrast of 10^-5^ translates into a low albedo of the planetary atmosphere (A_g_~0.05-0.15 for an assumed planetary radius in the range 1.5-0.9R_Jup_, as estimated from the planet's mass).
- ID:
- ivo://CDS.VizieR/J/A+A/576/A48
- Title:
- Radial velocity monitoring for 6 stars
- Short Name:
- J/A+A/576/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe radial-velocity time series obtained by HARPS on the 3.60m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD-11 4672. Their periods range from 492 to 1684-days, semi-major axes range from 1.2 to 2.69AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5M_Jup_. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663+/-8 and 1818+/-25-days, orbital eccentricities of 0.14+/-0.08 and 0.20+/-0.04, and minimum masses of 0.36+/-0.04 and 0.93+/-0.06M_Jup_. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557+/-0.0001-days and a minimum mass of 0.62+/-0.025M_Jup_. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet stars with typical 2m/s radial velocity precision.
