- ID:
- ivo://CDS.VizieR/J/ApJ/725/L186
- Title:
- Orbital eccentricities of 31535 G-dwarfs
- Short Name:
- J/ApJ/725/L186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We test four competing models that aim to explain the nature of stars in spiral galaxies that are well away (>1kpc) from the midplane, the so-called thick disk: the stars may have gotten there through orbital migration, through satellite mergers and accretion, or through heating of pre-existing thin disk stars. The eccentricity distribution of thick disk stars has recently been proposed as a diagnostic to differentiate between these mechanisms. Drawing on SDSS-DR7, we have assembled a sample of 31535 G-dwarfs with six-dimensional phase-space information and metallicities and have derived the orbital eccentricities for them.
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- ID:
- ivo://CDS.VizieR/J/A+A/473/829
- Title:
- Orbital elements of 156 spectroscopic binaries
- Short Name:
- J/A+A/473/829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a comprehensive, long-term monitoring programme aiming to improve our knowledge of such binary systems. We monitored the radial velocities of 1309 red giants in 187 open clusters with the Coravel spectrometers for 20 years, with a typical accuracy of 0.4km/s per observation. In total, 289 spectroscopic binaries were detected in the sample. We present first orbits for 67 systems and improved elements for another 64 previously published orbits, based on additional observations. For completeness, 25 published orbits are listed as well. The orbits are based on a total of 4039 observations, an average of 26 per system. Orbital periods range from 41.5 to 14722-days (40yrs), eccentricities from 0.00 to 0.81. The remaining systems have too long periods and/or inadequate phase coverage for an orbit determination at this time or too few observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/209
- Title:
- Orbital nature of 81 ellipsoidal red giant binaries
- Short Name:
- J/ApJ/835/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we collect a sample of 81 ellipsoidal red giant binaries in the Large Magellanic Cloud (LMC), and we study their orbital natures individually and statistically. The sample contains 59 systems with circular orbits and 22 systems with eccentric orbits. We derive orbital solutions using the 2010 version of the Wilson-Devinney code (Wilson & Devinney 1971ApJ...166..605W ; Wilson 1979ApJ...234.1054W, 1990ApJ...356..613W ; Wilson+ 2009, J/ApJ/702/403). The sample is selection-bias corrected, and the orbital parameter distributions are compared to model predictions for the LMC and to observations in the solar vicinity. The masses of the red giant primaries are found to range from about 0.6 to 9M_{sun}_ with a peak at around 1.5M_{sun}_, in agreement with studies of the star formation history of the LMC, which find a burst of star formation beginning around 4 Gyr ago. The observed distribution of mass ratios q=m_2_/m_1_ is more consistent with the flat q distribution derived for the solar vicinity by Raghavan+ (2010, J/ApJS/190/1) than it is with the solar vicinity q distribution derived by Duquennoy & Mayor (1991A&A...248..485D). There is no evidence for an excess number of systems with equal mass components. We find that about 20% of the ellipsoidal binaries have eccentric orbits, twice the fraction estimated by Soszynski+ (2004, J/AcA/54/347). Our eccentricity evolution test shows that the existence of eccentric ellipsoidal red giant binaries on the upper parts of the red giant branch (RGB) can only be explained if tidal circularization rates are ~1/100 the rates given by the usual theory of tidal dissipation in convective stars.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A95
- Title:
- Orbital solutions of eight close sdB binaries
- Short Name:
- J/A+A/562/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars (sdBs) with massive compact companions such as white dwarfs, neutron stars, or stellar-mass black holes. In a supplementary programme we obtained time-resolved spectroscopy of known hot subdwarf binary candidates. Here we present orbital solutions of eight close sdB binaries with orbital periods ranging from 0.1 to 10 days, which allow us to derive lower limits on the masses of their companions. Additionally, a dedicated photometric follow-up campaign was conducted to obtain light curves of the reflection-effect binary HS 2043+0615. We are able to constrain the most likely nature of the companions in all cases but one, making use of information derived from photometry and spectroscopy. Four sdBs have white dwarf companions, while another three are orbited by low-mass main sequence stars of spectral type M.
- ID:
- ivo://CDS.VizieR/J/AJ/156/194
- Title:
- Orbits of double-lined pairs in multiple stars
- Short Name:
- J/AJ/156/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic orbits are computed for inner pairs in nine hierarchical multiple systems (HIP 19639, 60845, 75663, 76816, 78163, 78416, 80448, 84789, and HD 105080) and for one simple binary HIP 61840. All subsystems are double-lined, and their periods range from 2.27 to 30.4 days. Five spectroscopic binaries are twins with equal masses. Each hierarchical system is discussed individually, providing estimates of outer periods, masses, orbital inclination, and axial rotation. For systems with three resolved visual components (HIP 60845 and 80448), the outer and inner visual orbits are determined, complementing the description of their architecture. The radial velocities of HIP 75663A, 76816B, and 78163B are found to be variable with long periods, implying that these hierarchies are 2 + 2 quadruples. The period-eccentricity relation for spectroscopic subsystems is discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/146/129
- Title:
- Orbits of 4 double-lined spectroscopic binaries
- Short Name:
- J/AJ/146/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Improved orbital elements for four A-star double-lined spectroscopic binaries have been determined with numerous new radial velocities. Three of the four systems, HR 1528, 2 Sge, and 18 Vul, have moderately short orbital periods of 7.05, 7.39, and 9.31 days, respectively, and also have circular or nearly circular orbits. Only HR 6993 with a period of 14.68 days has a significantly eccentric orbit. The close visual companion of 2 Sge has been detected spectroscopically, and its velocity measured. The orbital dimensions (a_1_sini and a_2_sini) and minimum masses (m_1_sin^3^i and m_2_ sin^3^i) of the short-period binary components all have accuracies of 0.5% or better. We determine basic properties of the individual stars and compare them with solar-abundance evolutionary tracks to estimate their masses. Half of the eight components may be synchronously or pseudosynchronously rotating.
- ID:
- ivo://CDS.VizieR/J/AJ/152/11
- Title:
- Orbits of four triple stars
- Short Name:
- J/AJ/152/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Each of the nearby triple systems HIP 7601, 13498, 23824, and 113597 (HD 10800, 18198, 35877, 217379) consist of solar-type dwarfs with comparable masses, where all three components are resolved spectrally, while the outer pairs are resolved both visually and spectrally. These stars are relatively young (between 100 and 600Myr) and chromospherically active (X-ray sources), although they rotate slowly. I determine the spectroscopic orbits of the inner subsystems (periods 19.4, 14.1, 5.6, 20.3days) and the orbits of the outer systems (periods 1.75, 51, 27, 500years, respectively). For HIP 7601 and 13498, the combined spectro-interferometric outer orbits produce direct measurement of the masses of all of the components, allowing for a comparison with stellar models. The 6708{AA} lithium line is present and its strength is measured in each component individually by subtracting the contributions of the other components. The inner and outer orbits of HIP 7601 are nearly circular, likely co-planar, and have a modest period ratio of 1:33. This study contributes to the characterization of hierarchical multiplicity in the solar neighborhood and provides data for testing stellar evolutionary models and chronology.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/2146
- Title:
- Orbits of open clusters in the Galaxy
- Short Name:
- J/MNRAS/399/2146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyse the kinematics and orbits for a sample of 488 open clusters (OCs) in the Galaxy. The velocity ellipsoid for our present sample is derived as ({sigma}(U),{sigma}(V),{sigma}(W)) = (28.7, 15.8, 11.0)km/s which represents a young thin-disc population. We also confirm that the velocity dispersions increase with the age of a cluster subsample. The orbits of OCs are calculated with three Galactic gravitational potential models. The errors of orbital parameters are also calculated considering the intrinsic variation of the orbital parameters and the effects of observational uncertainties. The observational uncertainties dominate the errors of derived orbital parameters. The vertical motions of clusters calculated using different Galactic disc models are rather different. The observed radial metallicity gradient of clusters is derived with a slope of b=-0.070+/-0.011dex/kpc. The radial metallicity gradient of clusters based on their apogalactic distances is also derived with a slope of b=-0.082+/-0.014dex/kpc. The distribution of derived orbital eccentricities for OCs is very similar to that derived for the field population of dwarfs and giants in the thin disc.
- ID:
- ivo://CDS.VizieR/J/AJ/124/1144
- Title:
- Orbits of 171 single-lined spectroscopic binaries
- Short Name:
- J/AJ/124/1144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 25,563 radial velocity measurements are reported for 1359 single-lined stars in the Carney-Latham sample of 1464 stars selected for high proper motion; for 171 of these, spectroscopic orbital solutions are derived. The radial velocities of nearly all of the 1464 stars defined in Paper XII (J/AJ/107/2240) have been monitored with the CfA Digital Speedometers (see Latham 1985, in IAU Colloq. 88, 21; and 1992, in IAU Colloq. 135, 110). Three nearly identical instruments have been used on the Multiple Mirror Telescope and 1.5 m Tillinghast Reflector at the F.L. Whipple Observatory atop Mount Hopkins, Arizona, and on the 1.5m Wyeth Reflector located at the Oak Ridge Observatory in the town of Harvard, Massachusetts. Echelle spectrographs have been used with photon counting intensified Reticon detectors to record about 45Angstroems of spectrum in a single order. Most of the spectra were centered near 5187Angstroems, but a significant number of the early spectra were centered near 5197Angstroems. The shift in central wavelength was adopted in order to include all three lines of the Mgb triplet, after it was fully appreciated that all the other lines in our spectral window became extremely weak for our most metal-poor stars. The spectral resolution is about 8.5km.s-1 for all our exposures, and the signal-to-noise ratios range from about 5 to 50 per resolution element.
- ID:
- ivo://CDS.VizieR/J/AJ/160/58
- Title:
- Orbits of spectro. binaries with CHARA Array. III.
- Short Name:
- J/AJ/160/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the visual orbits of two long-period spectroscopic binary stars, HD8374 and HD24546, using interferometric observations acquired with the Center for High Angular Resolution Astronomy (CHARA) Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5m and Fairborn 2.0 telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar parameters to the predictions of stellar evolution models. For HD8374, we find masses of M1=1.636{+/-}0.050M{sun} and M2=1.587{+/-}0.049M{sun}, radii of R1=1.84{+/-}0.05R{sun} and R2=1.66{+/-}0.12R{sun}, temperatures of Teff_1_=7280{+/-}110K and Teff-2-=7280{+/-}120K, and an estimated age of 1.0Gyr. For HD24546, we find masses of M1=1.434{+/-}0.014M{sun} and M2=1.409{+/-}0.014M{sun}, radii of R_1_=1.67{+/-}0.06R{sun} and R_2_=1.60{+/-}0.10R{sun}, temperatures of Teff_1_=6790{+/-}120K and Teff_2_=6770{+/-}90K, and an estimated age of 1.4Gyr. HD24546 is therefore too old to be a member of the Hyades cluster, despite its physical proximity to the group.