- ID:
- ivo://CDS.VizieR/J/A+AS/121/71
- Title:
- Orbits of 7 spectroscopic binaries in multiples
- Short Name:
- J/A+AS/121/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New close sub-systems are discovered in wide physical multiple stars. Elements of spectroscopic orbits are given for the components of quadruple systems ADS 1315C, 3608C, 3824C, 3991A and for the components of triple systems ADS 1849A, 6646A, 8861A. Physical parameters (magnitudes, spectral types, masses of individual components, distances to the systems, angular separations) are estimated by combining all available data. The nearby M dwarf ADS 8861A = Gliese 507A is a good candidate for speckle resolution. The very hot white dwarf discovered by Hodgkin et al. (1993) is likely to be an additional visual component to ADS 3824C, so this system may be quintuple; however, a search of 2.993d photometric periodicity possibly caused by the hot close companion is highly desirable.
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- ID:
- ivo://CDS.VizieR/J/AJ/158/222
- Title:
- Orbits of subsystems in multiple stars. VI.
- Short Name:
- J/AJ/158/222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thirteen spectroscopic orbits of late-type stars are determined from the high-resolution spectra taken with the CHIRON echelle spectrometer at the 1.5 m Cerro Tololo Inter-American Observatory telescope. Most (HIP 14194B, 40523A, 41171A, 51578A, 57572B, 59426A, 62852B, 66438A, 87813B, and 101472A) are inner subsystems in hierarchical multiple stars with three or four components. The periods range from 2.2 to 1131 days. Masses of the components, orbital inclinations, and projected rotation velocities are estimated, and the presence or absence of the lithium line is noted. In addition to those systems, HIP 57021 is a simple 54 day twin binary, and HIP 111598 is a compact triple-lined system with periods of 5.9 and 271 days. This object is likely old, but, nevertheless, the secondary component in the inner pair does not rotate synchronously with the orbit. The period-eccentricity diagram of 528 known inner low-mass spectroscopic subsystems (including 36 from this paper series) is given. The distribution of the inner periods is smooth, without any details around the tidal circularization period of ~10 days.
- ID:
- ivo://CDS.VizieR/J/AJ/156/48
- Title:
- Orbits of subsystems in six multiple stars. III.
- Short Name:
- J/AJ/156/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic orbits are computed for inner pairs in six nearby hierarchical multiple systems (HIP 35733, 95106/95110, 105441, 105585/105569, 105947, and 109951). Radial velocities and resolved measurements, when available, are used to derive combined sets of outer orbital elements for three systems. Each multiple system is discussed individually. Additionally, HIP 115087 is a simple 7.9-day single-lined binary. Although the minimum companion mass is substellar (in the brown dwarf desert regime), it appears to be a 0.2 solar-mass star in a low-inclination orbit.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A68
- Title:
- Orion A GMC 13CO and C18O maps
- Short Name:
- J/A+A/564/A68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive physical properties such as the optical depths and the column densities of ^13^CO and C^18^O to investigate the relationship between the far ultraviolet (FUV) radiation and the abundance ratios between ^13^CO and C^18^O.
- ID:
- ivo://CDS.VizieR/J/AZh/83/821
- Title:
- Orion Spiral Arm CAtalogue (OSACA)
- Short Name:
- J/AZh/83/821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We transformed radial velocities compiled from more than 1400 published sources, including the Geneva-Copenhagen survey of the solar neighborhood (2004, Nordstrom et al., Cat. <V/117>), into a uniform system based on the radial velocities of 854 standard stars in our list (Gontcharov, 2006, Cat. <III/252> ). This enabled us to calculate the average weighted radial velocities for more than 25000 HIPPARCOS stars located in the local Galactic spiral arm (Orion arm) with a median error of 1km/s. We use these radial velocities together with the stars coordinates, parallaxes, and proper motions to determine their Galactic coordinates and space velocities. These quantities, along with other parameters of the stars, are available from the continuously updated Orion Spiral Arm CAtalogue (OSACA) and the associated database. We perform a kinematic analysis of the stars by applying an Ogorodnikov-Milne model to the OSACA data. The kinematics of the nearest single and multiple main-sequence stars differ substantially.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A78
- Title:
- Orphan stream RR Lyrae and non-variables
- Short Name:
- J/A+A/648/A78
- Date:
- 07 Dec 2021 13:05:58
- Publisher:
- CDS
- Description:
- We present a chemo-dynamical study of the Orphan stellar stream using a catalog of RR Lyrae pulsating variable stars for which photometric, astrometric, and spectroscopic data are available. Employing low-resolution spectra from the Sloan Digital Sky Survey (SDSS), we determined line-of-sight velocities for individual exposures and derived the systemic velocities of the RR Lyrae stars. In combination with the stars' spectroscopic metallicities and Gaia EDR3 astrometry, we investigated the northern part of the Orphan stream. In our probabilistic approach, we found 20 single mode RR Lyrae variables likely associated with the Orphan stream based on their positions, proper motions, and distances. The acquired sample permitted us to expand our search to nonvariable stars in the SDSS dataset, utilizing line-of-sight velocities determined by the SDSS. We found 54 additional nonvariable stars linked to the Orphan stream. The metallicity distribution for the identified red giant branch stars and blue horizontal branch stars is, on average, -2.13+/-0.05dex and -1.87+/-0.14dex, with dispersions of 0.23 and 0.43dex, respectively. The metallicity distribution of the RR Lyrae variables peaks at -1.80+/-0.06dex and a dispersion of 0.25dex. Using the collected stellar sample, we investigated a possible link between the ultra-faint dwarf galaxy Grus II and the Orphan stream. Based on their kinematics, we found that both the stream RR Lyrae and Grus II are on a prograde orbit with similar orbital properties, although the large uncertainties on the dynamical properties render an unambiguous claim of connection difficult. At the same time, the chemical analysis strongly weakens the connection between both. We argue that Grus II in combination with the Orphan stream would have to exhibit a strong inverse metallicity gradient, which to date has not been detected in any Local Group system.
- ID:
- ivo://CDS.VizieR/J/AJ/160/6
- Title:
- OSMOS & modspec RVs of 30 cataclysmic variables
- Short Name:
- J/AJ/160/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopy and orbital periods Porb for 30 apparently nonmagnetic cataclysmic binaries with periods below ~3hr, nearly all of which are dwarf novae, mostly of the SU Ursae Majoris subclass. We then turn to the evidence supporting the prediction that short-period dwarf novae evolve toward longer periods after passing through a minimum period-the "period bounce" phenomenon. Plotting data from the literature reveals that for superhump period excess {epsilon}=(P_sh_-P_orb_)/P_orb_ below ~0.015, the period appears to increase with decreasing {epsilon}, agreeing at least qualitatively with the predicted behavior. Next, motivated by the long (decadal) outburst intervals of the WZ Sagittae subclass of short-period dwarf novae, we ask whether there could be a sizable population of "lurkers"-systems that resemble dwarf novae at minimum light, but which do not outburst over accessible timescales (or at all) and therefore do not draw attention to themselves. By examining the outburst history of the Sloan Digital Sky Survey sample of Cataclysmic Variables (CVs), which were selected by color and not by outburst, we find that a large majority of the color-selected dwarf-nova-like objects have been observed to outburst, and we conclude that "lurkers," if they exist, are a relatively minor part of the CV population.
- ID:
- ivo://CDS.VizieR/J/A+A/401/271
- Title:
- Outbursts in the Be star HR 2501
- Short Name:
- J/A+A/401/271
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several mostly unrelated periods or time scales characterize the variability of HR 2501. This star is a new lambda Eri star with a period of 0.79187d. This star also exhibits a mid- to long-term variability of characteristic time ~500d, most probably a consequence of the recurrent outbursts of matter from the rapidly rotating Be star towards its disk.
- ID:
- ivo://CDS.VizieR/J/MNRAS/485/2312
- Title:
- Outer Galactic disk A and F stars space motions
- Short Name:
- J/MNRAS/485/2312
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A and F stars can be used as probes of outer Galactic disk kinematics: here we extend the work of Harris et al. (2018, Cat. J/MNRAS/475/1680) by crossmatching their A/F sample with Gaia DR2 to bring in proper motions. These are combined with the already measured radial velocities and spectro-photometric distances to obtain full space motions. We use this sample of 1173 stars, located in two pencil-beam sightlines (l=178{deg} and l=118{deg}), to sample the Galactocentric velocity field out to almost R_G_=15kpc. We find there are significant differences in all three (radial, azimuthal and vertical) kinematic components between the two directions. The rotation curve is roughly flat in the anticentre direction, confirming and extending the result of Kawata et al. (2018MNRAS.479L.108K) thanks to the greater reach of our spectro-photometric distance scale. However at l=118{deg} the circular velocity rises outwards from R_G_=10.5kpc and there is a more pronounced gradient in radial motion than is seen at l=178{deg}. Furthermore, the A star radial motion differs from the F stars by ~10km/s. We discuss our findings in the context of perturbers potentially responsible for the trends, such as the central bar, spiral arms, the warp and external satellites. Our results at l=178{deg} are broadly consistent with previous work on K giants in the anticentre, but the kinematics at l=118{deg} in the Perseus region do not yet reconcile easily with bar or spiral arm perturbation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/275/591
- Title:
- Outer regions of Galactic Bulge
- Short Name:
- J/MNRAS/275/591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Digitized UK Schmidt plate photometry, calibrated with CCD photometry, is obtained in 18 regions over the Bulge. Stars are selected for spectroscopic follow-up from with a carefully chosen colour-magnitude window, optimized for efficient detection of bulge K giants. Some 1500 stellar spectra are obtained with the AAT AUTOFIB facility. We derive a radial velocity and metallicity for each star, and quantify the uncertainties in these measurements. Luminosity classification is derived both by visual classification and by using an automated routine based on Principal Component Analysis. There are two basic results from this survey: the discovery of the Sagittarius dwarf galaxy described by Ibata, Gilmore and Irwin (1994Natur.370..194I), and a study of the Galactic Bulge by Ibata and Gilmore (1995MNRAS.275..605I) The catalogue contains coordinates, photometry, radial velocities, luminosity classification and chemical abundances for approximately 1500 stars in lines of sight towards the Galactic Bulge. A detailed description of the selection of these stars, the methods used to derive the data, and the reliability of the data, is presented in the paper.
