- ID:
- ivo://CDS.VizieR/J/AJ/162/117
- Title:
- Radial velocity for 19 RR Lyrae
- Short Name:
- J/AJ/162/117
- Date:
- 21 Mar 2022 00:54:18
- Publisher:
- CDS
- Description:
- We report 272 radial velocities for 19 RR-Lyrae variables. For most of the stars we have radial velocities for the complete pulsation cycle. These data are used to determine robust center-of-mass radial velocities that have been compared to values from the literature in a search for evidence of binary systems. Center-of-mass velocities were determined for each star using Fourier Series and template fits to the radial velocities. Our center-of-mass velocities have uncertainties from {+/-}0.16km/s to {+/-}2.5km/s, with a mean uncertainty of {+/-}0.92km/s. We combined our center-of-mass velocities with values from the literature to look for deviations from the mean center-of-mass velocity of each star. Fifteen RR-Lyrae show no evidence of binary motion (BK And, CI And, Z CVn, DM Cyg, BK Dra, RR Gem, XX Hya, SZ Leo, BX Leo, TT Lyn, CN Lyr, TU Per, U Tri, RV UMa, and AV Vir). In most cases this conclusion is reached due to the sporadic sampling of the center-of-mass velocities over time. Three RR Lyrae show suspicious variation in the center-of-mass velocities that may indicate binary motion but do not prove it (SS Leo, ST Leo, and AO Peg). TU UMa was observed by us near a predicted periastron passage (at 0.14 in orbital phase) but the absence of additional center-of-mass velocities near periastron makes the binary detection, based on radial velocities alone, uncertain. Two stars in our sample show H{gamma} emission in phases 0.9-1.0: SS Leo and TU UMa.
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Search Results
1072. Radial velocity in Draco
- ID:
- ivo://CDS.VizieR/J/MNRAS/330/792
- Title:
- Radial velocity in Draco
- Short Name:
- J/MNRAS/330/792
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present stellar radial velocity data for the Draco dwarf spheroidal (dSph) galaxy obtained using the AF2/WYFFOS instrument combination on the William Herschel Telescope. Our data set consists of 186 member stars, 159 of which have good quality velocities, extending to a magnitude V~19.5 with a mean velocity precision of ~2km/s. As this survey is based on a high-precision photometric target list, it contains many more Draco members at large radii. For the first time, this allows a robust determination of the radial behaviour of the velocity dispersion in a dSph.
- 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/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/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.
- ID:
- ivo://CDS.VizieR/J/ApJ/818/34
- Title:
- Radial velocity monitoring of 5 FGK stars
- Short Name:
- J/ApJ/818/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of two new long-period giant planets orbiting the stars HD 95872 and HD 162004 ({psi}^1^ Dra B) by the McDonald Observatory planet search. The planet HD 95872b has a minimum mass of 4.6M_Jup_ and an orbital semimajor axis of 5.2AU. The giant planet {psi}^1^ Dra Bb has a minimum mass of 1.5M_Jup_ and an orbital semimajor axis of 4.4AU. Both of these planets qualify as Jupiter analogs. These results are based on over one and a half decades of precise radial velocity (RV) measurements collected by our program using the McDonald Observatory Tull Coude spectrograph at the 2.7m Harlan J. Smith Telescope. In the case of {psi}^1^ Dra B we also detect a long-term nonlinear trend in our data that indicates the presence of an additional giant planet, similar to the Jupiter-Saturn pair. The primary of the binary star system, {psi}^1^ Dra A, exhibits a very large amplitude RV variation due to another stellar companion. We detect this additional member using speckle imaging. We also report two cases --HD 10086 and HD 102870 ({beta} Virginis)-- of significant RV variation consistent with the presence of a planet, but that are probably caused by stellar activity, rather than reflexive Keplerian motion. These two cases stress the importance of monitoring the magnetic activity level of a target star, as long-term activity cycles can mimic the presence of a Jupiter-analog planet.
- ID:
- ivo://CDS.VizieR/J/AJ/157/52
- Title:
- Radial velocity observations in super-Earth systems
- Short Name:
- J/AJ/157/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use radial velocity (RV) observations to search for long-period gas giant companions in systems hosting inner super-Earth (1-4 R_{Earth}_, 1-10 M_{Earth}_) planets to constrain formation and migration scenarios for this population. We consistently refit published RV data sets for 65 stars and find nine systems with statistically significant trends indicating the presence of an outer companion. We combine these RV data with AO images to constrain the masses and semi-major axes of these companions. We quantify our sensitivity to the presence of long-period companions by fitting the sample with a power-law distribution and find an occurrence rate of 39%+/-7% for companions 0.5-20 M_Jup_ and 1-20 au. Half of our systems were discovered by the transit method, and half were discovered by the RV method. While differences in the RV baselines and number of data points between the two samples lead to different sensitivities to distant companions, we find that occurrence rates of gas giant companions in each sample are consistent at the 0.5{sigma} level. We compare the frequency of Jupiter analogs in these systems to the equivalent rate from field star surveys and find that Jupiter analogs are more common around stars hosting super-Earths. We conclude that the presence of outer gas giants does not suppress the formation of inner super-Earths, and that these two populations of planets instead appear to be correlated. We also find that the stellar metallicities of systems with gas giant companions are higher than those without companions, in agreement with the well-established metallicity correlation from RV surveys of field stars.