- ID:
- ivo://CDS.VizieR/J/AJ/152/10
- Title:
- Spectroscopy of subsystems in four multiple stars
- Short Name:
- J/AJ/152/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven spectroscopic orbits in nearby solar-type multiple stars are presented. The primary of the chromospherically active star HIP9642 is a 4.8day double-lined pair; the outer 420 year visual orbit is updated, but remains poorly constrained. HIP12780 is a quadruple system consisting of the resolved 6.7year pair FIN 379 Aa,Ab, for which the combined orbit, masses, and orbital parallax are determined here, and the single-lined binary Ba,Bb with a period of 27.8 days. HIP28790 is a young quintuple system composed of two close binaries, Aa,Ab and Ba,Bb, with periods of 221 and 13 days, respectively, and a single distant component C. Its subsystem Ba,Bb is peculiar, having a spectroscopic mass ratio of 0.89 but a magnitude difference of ~2.2mag. HIP64478 also contains five stars: the A-component is a 29year visual pair with a previously known 4 day twin subsystem, while the B-component is a contact binary with a period of 5.8hr, seen nearly pole-on.
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17502. Spectroscopy of Terzan 5
- ID:
- ivo://CDS.VizieR/J/ApJ/726/L20
- Title:
- Spectroscopy of Terzan 5
- Short Name:
- J/ApJ/726/L20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the chemical abundance analysis of 33 red giant stars belonging to the complex stellar system Terzan 5. We confirm the discovery of two stellar populations with distinct iron abundances: a relatively metal-poor component with [Fe/H]=-0.25+/-0.07rms and another component with [Fe/H]=+0.27+/-0.04rms, exceeding in metallicity any known Galactic globular cluster (GC). The two populations also show different [{alpha}/Fe] abundance ratios. The metal-poor component has an average [{alpha}/Fe]=+0.34+/-0.06rms, consistent with the canonical scenario for rapid enrichment by core collapse supernovae (SNe). The metal-rich component has [{alpha}/Fe]=+0.03+/-0.04rms, suggesting that the gas from which it formed was polluted by both type II and type Ia SNe on a longer timescale. Neither of the two populations shows evidence of the [Al/Fe] over [O/Fe] anti-correlation that is typically observed in Galactic GCs. Because these chemical abundance patterns are unique, we propose that Terzan 5 is not a true GC, but a stellar system with a much more complex history of star formation and chemical enrichment.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/209
- Title:
- Spectroscopy of the B[e] star VES 695
- Short Name:
- J/ApJ/700/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003-2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak LiI6708{AA} line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral-type primary companion of a luminosity logL/L_{sun}_=3.9+/-0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0+/-0.3kpc from the Sun.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A107
- Title:
- Spectroscopy of the Eri 2 cluster
- Short Name:
- J/A+A/635/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been shown that the ultra-faint dwarf galaxy Eridanus 2 may host a stellar cluster in its centre. If this cluster is shown to exist, it can be used to set constraints on the mass and abundance of massive astrophysical compact halo objects (MACHOs) as a form of dark matter. Previous research has shown promising expectations in the mass range of 10-100M_{sun}_, but lacked spectroscopic measurements of the cluster. We aim to provide spectroscopic evidence regarding the nature of the putative star cluster in Eridanus 2 and to place constraints on MACHOs as a constituent of dark matter. We present spectroscopic observations of the central square arcminute of Eridanus 2 from MUSE-Faint, a survey of ultrafaint dwarf galaxies with the Multi Unit Spectroscopic Explorer on the Very Large Telescope. We derived line-of-sight velocities for possible member stars of the putative cluster and for stars in the centre of Eridanus 2. We discuss the existence of the cluster and determine new constraints for MACHOs using the Fokker-Planck diffusion approximation. Out of 182 extracted spectra, we identify 26 member stars of Eridanus 2, seven of which are possible cluster members. We find intrinsic mean line-of-sight velocities of 79.7^+3.1^_3.8_km/s and 76.0^+3.2^_3.7_km/s for the cluster and the bulk of Eridanus 2, respectively, as well as intrinsic velocity dispersions of <7.6km/s (68-% upper limit) and 10.3^+3.9^_3.2_km/s, respectively. This indicates that the cluster most likely exists as a distinct dynamical population hosted by Eridanus 2 and that it does not have a surplus of dark matter over the background distribution. Among the member stars in the bulk of Eridanus 2, we find possible carbon stars, alluding to the existence of an intermediate-age population.We derived constraints on the fraction of dark matter that can consist of MACHOs with a given mass between 1-10^5^M_{sun}_. For dark matter consisting purely of MACHOs, the mass of the MACHOs must be less than 7.6M_{sun}_ and 44M_{sun}_ at a 68- and 95-% confidence level, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/94
- Title:
- Spectroscopy of the fields of gravitational lenses
- Short Name:
- J/ApJ/850/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Strong gravitational lensing provides an independent measurement of the Hubble parameter (H_0_). One remaining systematic is a bias from the additional mass due to a galaxy group at the lens redshift or along the sightline. We quantify this bias for more than 20 strong lenses that have well-sampled sightline mass distributions, focusing on the convergence {kappa} and shear {gamma}. In 23% of these fields, a lens group contributes >=1% convergence bias; in 57%, there is a similarly significant line-of-sight group. For the nine time-delay lens systems, H0 is overestimated by 11_-2_^+3^% on average when groups are ignored. In 67% of fields with total {kappa}>=0.01, line-of-sight groups contribute >~2x more convergence than do lens groups, indicating that the lens group is not the only important mass. Lens environment affects the ratio of four (quad) to two (double) image systems; all seven quads have lens groups while only 3 of 10 doubles do, and the highest convergences due to lens groups are in quads. We calibrate the {gamma}-{kappa} relation: log({kappa}_tot_)=(1.94+/-0.34)log({gamma}_tot_)+(1.31+/-0.49) with an rms scatter of 0.34dex. Although shear can be measured directly from lensed images, unlike convergence, it can be a poor predictor of convergence; for 19% of our fields, {kappa} is >~2{gamma}. Thus, accurate cosmology using strong gravitational lenses requires precise measurement and correction for all significant structures in each lens field.
- ID:
- ivo://CDS.VizieR/J/AJ/153/188
- Title:
- Spectroscopy of the foreground population in Orion A
- Short Name:
- J/AJ/153/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a spectroscopic survey of the foreground population in Orion A with MMT/Hectospec. We use these data, along with archival spectroscopic data and photometric data, to derive spectral types, extinction values, and masses for 691 stars. Using the Spitzer Space Telescope data, we characterize the disk properties of these sources. We identify 37 new transition disk (TD) objects, 1 globally depleted disk candidate, and 7 probable young debris disks. We discover an object with a mass of less than 0.018-0.030 M_{sun}_, which harbors a flaring disk. Using the H{alpha} emission line, we characterize the accretion activity of the sources with disks, and confirm that the fraction of accreting TDs is lower than that of optically thick disks (46%+/-7% versus 73%+/-9%, respectively). Using kinematic data from the Sloan Digital Sky Survey and APOGEE INfrared Spectroscopy of the Young Nebulous Clusters program (IN-SYNC), we confirm that the foreground population shows similar kinematics to their local molecular clouds and other young stars in the same regions. Using the isochronal ages, we find that the foreground population has a median age of around 1-2 Myr, which is similar to that of other young stars in Orion A. Therefore, our results argue against the presence of a large and old foreground cluster in front of Orion A.
- ID:
- ivo://CDS.VizieR/J/ApJ/691/1387
- Title:
- Spectroscopy of the Galactic bar. I.
- Short Name:
- J/ApJ/691/1387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Fabry-Perot absorption line imaging spectroscopy to measure radial velocities using the CaII line in 3360 stars toward three lines of sight in the Milky Way's bar: Baade's Window and offset position at (l,b)~(+/-5.0,-3.5{deg}). This sample includes 2488 bar red clump giants, 339 bar M/K-giants, and 318 disk main-sequence stars. We measure the first four moments of the stellar velocity distribution of the red clump giants, and find it to be symmetric and flat-topped. We also measure the line-of-sight average velocity and dispersion of the red clump giants as a function of distance in the bar.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1707
- Title:
- Spectroscopy of the LV2 proplyd in Orion
- Short Name:
- J/AJ/130/1707
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high spatial resolution spectroscopic observations of the proplyd 167-317 (LV2) near the Trapezium cluster in the Orion Nebula, obtained during the system verification run of the Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU) at the Gemini South Observatory. We have detected 38 forbidden and permitted emission lines associated with the proplyd and its redshifted jet.
- ID:
- ivo://CDS.VizieR/J/AJ/149/195
- Title:
- Spectroscopy of the quadruple system HD 91962
- Short Name:
- J/AJ/149/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The young nearby solar-type star HD 91962 is a rare quadruple system where three companions revolve around the main component with periods of 170.3days, 8.85years, and 205years. The two outer orbits are nearly co-planar, and all orbits have small eccentricities. We refine the visual orbit of the outer pair and determine the combined spectro-interferometric orbit of the middle 8.8year pair and the spectroscopic orbit of the inner binary. The middle and inner orbits are likely locked in a 1:19 resonance, and the ratio of the outer and middle periods is ~23. The masses of all components are estimated (inside-out: 1.14, 0.32, 0.64, 0.64 solar mass). The dynamical parallax is 27.4+/-0.6mas. We speculate that this multiple system originated from collapse of an isolated core and that the companions migrated in a dissipative disk. Other multiple systems with similar features (co-planarity, small eccentricity, and period ratio around 20) are known.
- ID:
- ivo://CDS.VizieR/J/other/Ap/54.81
- Title:
- Spectroscopy of {theta}1 Ori C system
- Short Name:
- J/other/Ap/54.81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectral-double system escaping from multiple system theta1 Ori C is investigated. Radial velocities of both components are measured, for them are constructed and solved curves of radial velocity. Physical parameters of stars and their chemical composition are determined.