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- ID:
- ivo://CDS.VizieR/J/ApJS/105/419
- Title:
- Spectral Atlas of Carbon Stars
- Short Name:
- J/ApJS/105/419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The authors compiled this moderate-resolution spectral atlas to aid in the classification of carbon stars on the Revised MK System (Keenan 1993PASP..105..905K) as refined and extended by the present work. Hence the main purpose of this atlas is to permit rapid and reasonably accurate comparison of the properties of carbon stars in the Solar neighborhood with those in the Galactic bulge, the Magellanic Clouds, and in other nearby external systems. The classification scheme employed makes no assumptions about evolutionary status of the stars but is based entirely on observable criteria. Spectra of 39 stars are presented in detail, along with a catalog of 119 carbon stars classified according to the Revised MK System; the catalog lists also the variability type from Kholopov (1985), and the instrument used. The table is a modified version of table 4 in the source reference. This classification catalog uses not only the stars we observed (the spectral data in this catalog) but also used other material -- photographic plates and some of the stars in the high resolution barnbaum atlas. Stars observed solely with those two instruments are so noted. The spectral files are the data for the standard Carbon Stars in Figs 1 and 2 of the paper.
- ID:
- ivo://CDS.VizieR/J/A+A/508/309
- Title:
- Spectral atlas of HD 50138
- Short Name:
- J/A+A/508/309
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed spectral variation of HD50138 led different authors in the literature to classify it in a very large range of spectral types and luminosity classes (from B5 to A0 and III to Ia) and at different evolutionary stages, as either an HAeBe star or a classical Be. Based on new high-resolution optical spectroscopic data from 1999 and 2007, we perform a detailed spectral description, presenting the variations seen and discussing their possible origin. We tentatively suggest that a new shell phase could have taken place prior to our observations in 2007. We derive the interstellar extinction to HD50138 by taking into account the influences of the circumstellar matter in the form of dust and an ionized disk. We find a color excess value of E(B-V)=0.08mag. Based on photometric data from the literature and the new Hipparcos distance, we obtain a revised set of parameters for HD50138, suggesting that it is a B6-7 III-V star. A discussion about the different evolutionary scenarios is also provided.
- ID:
- ivo://CDS.VizieR/J/A+A/465/993
- Title:
- Spectral atlas of massive stars around He I
- Short Name:
- J/A+A/465/993
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a digital atlas of peculiar, high-luminosity massive stars in the near-infrared region (10470-11000{AA}) at medium resolution (R~7000). The spectra are centered around HeI 10830{AA}, which is formed in the wind of those stars, and is a crucial line to obtain their physical parameters. The instrumental configuration also sampled a rich variety of emission lines of FeII, MgII, CI, NI, and Pa{gamma}. Secure identifications for most spectral lines are given, based on synthetic atmosphere models calculated by our group. We also propose that two unidentified absorption features have interstellar and/or circumstellar origin. For the strongest one (10780{AA}) an empirical calibration between E(B-V) and equivalent width is provided. The atlas displays the spectra of massive stars organized in four categories, namely Be stars, OBA Iape (or luminous blue variables, LBV candidates and ex/dormant LBVs), OB supergiants and Wolf-Rayet stars. For comparison, the photospheric spectra of non emission-line stars are presented. Selected LBVs were observed in different epochs from 2001 to 2004, and their spectral variability reveals that some stars, such as eta Car, AG Car and HR Car, suffered dramatic spectroscopic changes during this time interval.
- ID:
- ivo://CDS.VizieR/J/MNRAS/382/1353
- Title:
- Spectral atlas of omega Cen post-MS stars
- Short Name:
- J/MNRAS/382/1353
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectral atlas of the post-main-sequence population of the most massive Galactic globular cluster, omega Centauri. Spectra were obtained of more than 1500 stars selected as uniformly as possible from across the (B, B-V) colour-magnitude diagram of the proper motion cluster member candidates of van Leeuwen et al. (2000, Cat. <J/A+A/360/472>). The spectra were obtained with the 2dF multifibre spectrograph at the Anglo-Australian Telescope, and cover the approximate range {lambda}~3840-3940{AA} at a resolving power of {lambda}/{Delta}{lambda}~=2000. This constitutes the most comprehensible spectroscopic survey of a globular cluster. We measure the radial velocities, effective temperatures, metallicities and surface gravities by fitting ATLAS9 stellar atmosphere models. We analyse the cluster membership and stellar kinematics, interstellar absorption in the Ca II K line at 3933{AA}, the RR Lyrae instability strip and the extreme horizontal branch, the metallicity spread and bimodal CN abundance distribution of red giants, nitrogen and s-process enrichment, carbon stars, pulsation-induced Balmer line emission on the asymptotic giant branch (AGB), and the nature of the post-AGB and UV-bright stars. Membership is confirmed for the vast majority of stars, and the radial velocities clearly show the rotation of the cluster core. We identify long-period RR Lyrae-type variables with low gravity, and low-amplitude variables coinciding with warm RR Lyrae stars. A barium enhancement in the coolest red giants indicates that third dredge-up operates in AGB stars in omega Cen. This is distinguished from the pre-enrichment by more massive AGB stars, which is also seen in our data. The properties of the AGB, post-AGB and UV-bright stars suggest that red giant branch (RGB) mass loss may be less efficient at very low metallicity, [Fe/H]<<1, increasing the importance of mass loss on the AGB. The catalogue and spectra are made available via Centre Donnees de Strasbourg (CDS).
- ID:
- ivo://CDS.VizieR/J/A+AS/114/499
- Title:
- Spectral Atlas of P Cygni in range 4840-6760A
- Short Name:
- J/A+AS/114/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the coude spectrograph of the NAO 2m RCC telescope at the Rhodope Mountains, Bulgaria, 11 spectra in the wavelength range from 4840 to 6760A of P Cygni were obtained during the years 1981, 1983 and 1985. By averaging these spectra we achieved a S/N-ratio of about 50. Here we present a spectral atlas with complete line identifications. Apart from the lines listed by de Groot (1969) many pure bright lines are identified. Most of them are lines of FeIII with high multiplet numbers and NII. Further emission lines are those of SiII multiplets 2, 4 and 5. A new feature is SII spectrum in absorption and emission. In addition to the forbidden lines discovered by Stahl et al. (1991, 1993) three new lines, [FeII19] {lambda}5159, [FeII18] {lambda}5273 and [FeII34] {lambda}5477 are identified. The presence of some [TiII9] lines as well as the red lines of [NII1] is considered as quite probable.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1758
- Title:
- Spectral atlas of peculiar stars
- Short Name:
- J/AJ/140/1758
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an Echelle+CCD, high S/N, high resolution (R=20000) spectroscopic atlas of 108 well-known objects representative of the most common types of peculiar and variable stars. The wavelength interval extends from 4600 to 9400{AA}, and includes the RAVE, Gaia and HERMES wavelength ranges. Multi-epoch spectra are provided for the majority of observed stars. A total of 425 spectra of peculiar stars are presented, which have been collected during 56 observing nights between November 1998 and August 2002. The spectra are given in FITS format and heliocentric wavelengths, with accurate subtraction of both the sky background and the scattered light. Auxiliary material useful for custom applications (telluric dividers, spectro-photometric stars, flat-field tracings) is also provided. The atlas aims to provide a homogeneous database of the spectral appearance of stellar peculiarities, a tool useful both for classification purposes and inter-comparison studies. It could also serve the planning for and training of automated classification algorithms designed for RAVE, Gaia, HERMES and other large scale spectral surveys. The spectrum of XX Oph is discussed in some detail as an example of the content of the present atlas.
- ID:
- ivo://CDS.VizieR/J/AJ/160/52
- Title:
- Spectral classification for 631 {rho}Puppis stars
- Short Name:
- J/AJ/160/52
- Date:
- 09 Mar 2022
- Publisher:
- CDS
- Description:
- The {rho}Puppis stars are mid-F-type stars that show peculiar chemical-abundance patterns similar to those of the Am stars. Typically they exhibit overabundances of iron-peak elements such as Fe and Ni and s- and r-process elements such as Sr and Eu, and underabundances of certain other elements including He, Ca, and Sc. It has been proposed that these stars are evolving Am stars passing through the short-lived phase that occurs between the re-establishment of convection and the consequent erasure of their chemical peculiarities. In this paper we suggest a second hypothesis: these stars may have acquired their peculiar abundance patterns in a fashion similar to the Barium stars, i.e., they may have gained the s-process element enhancements via mass transfer from a once asymptotic giant-branch companion star, now turned white dwarf. This study will detail our efforts to investigate the {rho}Puppis stars with regard to these two hypotheses, with a view to understanding these stars and their significance in terms of stellar evolution. We have performed a spectral classification survey, and a detailed chemical-abundance analysis of selected {rho}Puppis stars. This paper gives an overview of the {rho}Puppis stars and describes the spectral classification survey which has increased the number of {rho}Puppis stars currently known from 6 to 49. A future paper will describe the chemical-abundance analysis which should provide insight into the nature of these stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/143/513
- Title:
- Spectral classification of close binaries
- Short Name:
- J/ApJS/143/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 135 stars with composite spectra has been observed in the near-UV spectral region with the Aurelie spectrograph at the Observatoire de Haute-Provence. Using the spectral classifications of the cool components previously determined with near infrared spectra, we obtained reliable spectral types of the hot components of the sample systems. The hot components were isolated by the subtraction method using MK standards as surrogates of the cool components. We also derived the visual magnitude differences between the components using Willstrop's normalized stellar flux ratios. We propose a photometric model for each of these systems on the basis of our spectroscopic data and the Hipparcos data.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/135
- Title:
- Spectral classifications of 180 IR stars
- Short Name:
- J/A+AS/123/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 180 supposedly composite-spectrum stars has been studied on the basis of spectra obtained in the near infrared (8370-8780{AA}) at a dispersion of 33{AA}/mm. The objective was to study the cooler components of the systems. Of our sample, 120 are true composite spectra, 35 are hot spectra of types B, F and 25 are Am stars. We find a strong concentration of the cooler components of the composite spectra around G8III. In view of the difficulty of classifying composite spectra, because of the superposition of an early type dwarf and a late type giant or supergiant spectrum, we have made several tests to control the classification based upon the infrared region. Since all tests gave positive results, we conclude that our classifications can be considered as being both reliable and homogeneous.
