- ID:
- ivo://CDS.VizieR/J/AJ/103/267
- Title:
- Spectrocopy of hot stars in galactic halo
- Short Name:
- J/AJ/103/267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents spectroscopy for 769 hot stars from the HK objective-prism/interference-filter survey of Beers et al. (1985), 193 of which have also available broadband UBV colors. When available, photometric information is used to obtain estimates of the surface temperature for degenerates and for O- and B-type subdwarfs, based on previously derived calibrations. Several extremely hot (T(eff) greater than 50,000 K) He-rich sdO stars are identified. Out of 769 stars in this sample, 551 are clearly identified on the basis of their Balmer line profiles as field horizontal-branch (FHB) or mid-to late-type A stars. The A stars exhibit rotation and line-of-sight dispersion consistent with membership in the galactic thick disk. The FHB stars exhibit kinematic properties which suggest a transition from thick disk to halo.
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- ID:
- ivo://CDS.VizieR/J/ApJ/691/672
- Title:
- Spectrocopy of YSOs in Serpens molecular cloud
- Short Name:
- J/ApJ/691/672
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of an optical spectroscopic survey designed to confirm the youth and determine the spectral types among a sample of young stellar object (YSO) candidates in the Serpens molecular cloud. We observed 150 infrared (IR) excess objects previously discovered by the Spitzer Legacy Program "From Molecular Cores to Planet-Forming Disks" (c2d), bright enough for subsequent Spitzer/InfraRed Spectrograph (IRS) spectroscopy. We obtained 78 optical spectra of sufficient signal-to-noise for analysis. Extinctions, effective temperatures, and luminosities are estimated for this sample, and used to construct Hertzsprung-Russell (H-R) diagrams for the population. We identified 20 background giants contaminating the sample, based on their relatively high extinction, position in the H-R diagram, the lack of H{alpha} emission and relatively low IR excess. Such strong background contamination (25%) is consistent with the location of Serpens being close to the Galactic plane (5{deg} Galactic latitude). The remaining 58 stars (75%) were all confirmed to be young, mostly K- and M-type stars that are presumed to belong to the cloud. Our analysis shows that the majority of the IR excess objects detected in Serpens are actively accreting, young T-Tauri stars.
- ID:
- ivo://CDS.VizieR/J/A+A/285/1
- Title:
- Spectrographic study of Kiso UV-excess galaxies
- Short Name:
- J/A+A/285/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/621/A6
- Title:
- Spectro-interferometric observation of SW Vir
- Short Name:
- J/A+A/621/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near-infrared spectro-interferometric observation of the non-Mira-type, semiregular asymptotic giant branch star SW Vir. Our aim is to probe the physical properties of the outer atmosphere with spatially resolved data in individual molecular and atomic lines. We observed SW Vir in the spectral window between 2.28 and 2.31 micron with the near-infrared interferometric instrument AMBER at ESO's Very Large Telescope Interferometer (VLTI). Thanks to AMBER's high spatial resolution and high spectral resolution of 12000, the atmosphere of SW Vir has been spatially resolved not only in strong CO first overtone lines but also in weak molecular and atomic lines of H_2_O, CN, HF, Ti, Fe, Mg, and Ca. While the uniform-disk diameter of the star is 16.23+/-0.20mas in the continuum, it increases up to 22-24mas in the CO lines. Comparison with the MARCS photospheric models reveals that the star appears larger than predicted by the hydrostatic models not only in the CO lines but also even in the weak molecular and atomic lines. We found that this is primarily due to the H2O lines (but also possibly due to the HF and Ti lines) originating in the extended outer atmosphere. Although the H_2_O lines manifest themselves very little in the spatially unresolved spectrum, the individual rovibrational H_2_O lines from the outer atmosphere can be identified in the spectro-interferometric data. Our modeling suggests an H_2_O column density of 10^19^-10^20^cm^-2^ in the outer atmosphere extending out to ~2R*. Our study has revealed that the effects of the nonphotospheric outer atmosphere are present in the spectro-interferometric data not only in the strong CO first overtone lines but also in the weak molecular and atomic lines. Therefore, analyses of spatially unresolved spectra, such as for example analyses of the chemical composition, should be carried out with care even if the lines appear to be weak.
- ID:
- ivo://CDS.VizieR/J/MNRAS/489/2595
- Title:
- Spectro-interferometry of 8 evolved stars
- Short Name:
- J/MNRAS/489/2595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine the physical parameters of the outer atmosphere of a sample of eight evolved stars, including the red supergiant {alpha} Scorpii, the red giant branch stars {alpha} Bootis and {gamma} Crucis, the K giant {lambda} Velorum, the normal M giants BK Virginis and SW Virginis, and the Mira star W Hydrae (in two different luminosity phases) by spatially resolving the stars in the individual carbon monoxide (CO) first overtone lines. We used the Astronomical Multi-BEam combineR (AMBER) instrument at the Very Large Telescope Interferometer (VLTI), in high-resolution mode ({lambda}/{Delta}{lambda}~=12000) between 2.28 and 2.31um in the K band. The maximal angular resolution is 10mas, obtained using a triplet telescope configuration, with baselines from 7 to 48m. By using a numerical model of a molecular atmosphere in a spherical shells (MOLsphere), called PAMPERO (an acronym for the 'physical approach of molecular photospheric ejection at high angular resolution for evolved stars'), we add multiple extended CO layers above the photospheric MARCS model at an adequate spatial resolution. We use the differential visibilities and the spectrum to estimate the size (R) of the CO MOLsphere, its column density (NCO) and temperature (Tmol) distributions along the stellar radius. The combining of the {chi}^2^ minimization and a fine grid approach for uncertainty analysis leads to reasonable NCO and Tmol distributions along the stellar radius of the MOLsphere.
- ID:
- ivo://CDS.VizieR/J/ApJ/660/1398
- Title:
- Spectro. monitoring of HDE 245770 and X Per
- Short Name:
- J/ApJ/660/1398
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from an H{alpha} monitoring campaign of the Be X-ray binary systems HDE 245770 = A0535+26 and X Per. We use the H{alpha} equivalent widths together with adopted values of the Be star effective temperature, disk inclination, and disk outer boundary to determine the half-maximum emission radius of the disk as a function of time.
- ID:
- ivo://CDS.VizieR/VII/141
- Title:
- Spectrophotometric Atlas of Galaxies
- Short Name:
- VII/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains 56 spectra: 55 galaxy spectra, and one night sky spectrum, which is included for users wishing to check for low-level spurious features in the galaxy spectra. The file "spectra.dat" contains a summary of the spectra. The user should consult the paper for details of the observations and a discussion of the limitations of the spectrophotometry. The spectra are integrated measurements made with apertures comparable to the diameters of the galaxies. The original spectra have been combined, rebinned to a common wavelength scale, and normalized in flux to unity at a reference wavelength of 555nm. An atmospheric extinction correction has been applied to the data, but otherwise they are not corrected for reddening, redshift, etc. The spectral range covered is 365-710 nm and the resolution is 5-8{AA}. Each spectrum consists in 1726 normalized flux values spaced each 2{AA}, stored as a file in the subdirectory "sp". Tests show that the spectrophotometry is accurate to the few percent level over small wavelength regions, and at the 10% level over the entire wavelength range. Although the data are useful for a variety of applications, the user should be forewarned that they may not be suitable for applications requiring precision colors over a long wavelength baseline (e.g., computation of K-corrections, some spectral synthesis applications).
- ID:
- ivo://CDS.VizieR/VII/102
- Title:
- Spectrophotometric Atlas of Standard Stellar Spectra
- Short Name:
- VII/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuous spectrophotometry has been obtained for 200 objects at a resolution of 10-17 A over the wavelength region 360-1000nm. Kron-Cousins BVRI colors are computed for the spectra and compared with published photoelectric photometry. The (V-R)_C color index is used to group the individual observations to form standard spectra types by stellar class. The standard groups include a solar abundance sequence of most spectral types and luminosity classes, metal-rich and metal weak G-K giant-branch sequences, and horizontal-branch giants. The standard spectra are presented in FITS files, of which a summary is contained in the "list.dat" file.
- ID:
- ivo://CDS.VizieR/J/A+A/383/188
- Title:
- Spectrophotometric atlas of symbiotic stars
- Short Name:
- J/A+A/383/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A multi-epoch, absolute-fluxed spectral atlas extending from about 3200 to 9000{AA} is presented for 130 symbiotic stars, including members of the LMC, SMC and Draco dwarf galaxies. The fluxes are accurate to better than 5% as shown by comparison with Tycho and ground-based photometric data. The spectra of 40 reference objects (MK cool giant standards, Mira and Carbon stars, planetary nebulae, white dwarfs, hot sub-dwarfs, Wolf-Rayet stars, classical novae, VV Cep and Herbig Ae/Be objects) are provided to assist the interpretation of symbiotic star spectra. Astrometric positions and counterparts in astrometric catalogues are derived for all program symbiotic stars. The spectra are available in electronic form from the authors.
- ID:
- ivo://CDS.VizieR/III/202
- Title:
- Spectrophotometric Catalogue of Stars
- Short Name:
- III/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains the absolute energy distribution of the 1147 stars of different spectral type and luminosity classes in the range of 3225-7575A with the step 50A. The observations were made in the Fessenkov Astrophysical Institute (AlmaAta,Kazakstan, height 1450m) during 1968-1986 using spectrum scanner with photo-multiplier tube attached to the 50cm Cassegrain telescope. Standards are Beta Ari, Gamma Ori, Beta Tau, Alpha Leo, Eta UMa, Alpha Lyr, Alpha Aql and Alpha Peg, based on the absolute energy distribution of Vega as given Hayes(1985). The average accuracy of the catalogue data is 3.5%.