- ID:
- ivo://CDS.VizieR/J/ApJ/518/859
- Title:
- Revision of MK luminosity classes
- Short Name:
- J/ApJ/518/859
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hipparcos parallaxes of cool giants are utilized in two ways in this paper. First, a plot of reduced parallaxes of stars brighter than 6.5, as a function of spectral type, for the first time separates members of the clump from stars in the main giant ridge. A slight modification of the MK luminosity standards has been made so that luminosity class IIIb defines members of the clump, and nearly all of the class III stars fall within the main giant ridge. Second, a new calibration of MK luminosity classes III and IIIb in terms of visual absolute magnitudes has been made.
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- ID:
- ivo://CDS.VizieR/J/A+A/461/977
- Title:
- Rosat North Ecliptic survey stellar population
- Short Name:
- J/A+A/461/977
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- X-ray surveys are a very efficient mean of detecting young stars and therefore allow us to study the young stellar population in the solar neighborhood and the local star formation history in the last billion of years. We want to study the young stellar population in the solar neighborhood, to constrain its spatial density and scale height as well as the recent local star formation history. We analyze the stellar content of the ROSAT North Ecliptic Pole survey, and compare the observations with the predictions derived from stellar galactic model. Since the ROSAT NEP survey is sensitive at intermediate fluxes is able to sample both the youngest stars and the intermediate age stars (younger than 10^9^years), linking the shallow and deep flux surveys already published in the literature. We confirm the existence of an excess of yellow stars in our neighborhood previously seen in shallow survey, which is likely due to a young star population not accounted for in the model. However the excellent agreement between observations and predictions of dM stars casts some doubt on the real nature of this active population.
- ID:
- ivo://CDS.VizieR/V/15
- Title:
- SAO and Supplementary Data
- Short Name:
- V/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This SAO catalogue (Smithsonian Astrophysical Observatory Catalogue of 258,997 stars, 1966; see catalog <I/131>), connected to the CSI (Catalogue of Stellar Identifications, see Ochsenbein et al. 1981), enables researchers to retrieve reliable astrophysical data for about 20,000 stars. This includes SAO identifications, CSI identifications, equatorial coordinates (B1950), Galactic coordinates, proper motions, photometric data, spectral classifications, radial velocity, etc. The SAO/HD cross index for about 188,000 stars allows users to find (or enter) the catalog with the HD number of the star. The notes contain detected errors, the value of the trigonometric parallax taken from the Jenkins' (1952, 1963) catalogues, the double star designation ADS or IDS, and the name of the star.
- ID:
- ivo://CDS.VizieR/J/AJ/123/3409
- Title:
- SDSS M, L, and T dwarfs
- Short Name:
- J/AJ/123/3409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive sample of M, L, and T dwarfs identified in the Sloan Digital Sky Survey (SDSS) has been compiled. The sample of 718 dwarfs includes 677 new objects (629 M dwarfs and 48 L dwarfs), together with 41 that have been previously published. All new objects and some of the previously published ones have new optical spectra obtained either with the SDSS spectrographs or with the Apache Point Observatory 3.5 m ARC telescope. Spectral types and SDSS colors are available for all objects; approximately 35% also have near-infrared magnitudes measured by 2MASS (Two Micron All Sky Survey) or on the Mauna Kea system. We use this sample to characterize the color-spectral type and color-color relations of late-type dwarfs in the SDSS filters and to derive spectroscopic and photometric parallax relations for use in future studies of the luminosity and mass functions based on SDSS data. We find that the i*-z* and i*-J colors provide good spectral type and absolute magnitude (Mi*) estimates for M and L dwarfs. Our distance estimates for the current sample indicate that SDSS is finding early M dwarfs out to ~1.5kpc, L dwarfs to ~100pc, and T dwarfs to ~20pc. The T dwarf photometric data show large scatter and are therefore less reliable for spectral type and distance estimation.
- ID:
- ivo://CDS.VizieR/III/42
- Title:
- Selected MK Spectral Types
- Short Name:
- III/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog provides a single spectral type for each star listed in the La Plata catalog (Jaschek, Conde and de Sierra 1964; catalog <III/18>) and in the MK Extension (Kennedy 1978; see catalog <III/78>). In all cases the classifications are selected from those in the literature and have not been made by the author specifically for this compilation. A selected classification is considered to be the best one but is not necessarily a good one. If only one classification exists for a given object, it is given, regardless of its quality. The classifications were selected using a weighting system, with highest weight being given to classifications made by Morgan and/or Keenan, somewhat lower weight to those made by other spectral classification experts and various lower weights to those made by other workers. Classifications using designations that do not appear in the MK system have been excluded, as have objective-prism classifications, except where no slit spectra were available. The catalog contains a running number in one of the original catalogs (sequential numbers in the machine versions), identification of the original catalog, star identification (HD, DM, miscellaneous designations), equatorial coordinates (B1900), magnitude, V if available, m(v) otherwise) for reference purposes, reference number in the original catalog, selected classification, dispersion information, and standardized reference.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/2647
- Title:
- Sgr dSph stars spectral classification
- Short Name:
- J/MNRAS/427/2647
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectra of 1142 colour-selected stars in the direction of the Sagittarius Dwarf Spheroidal (Sgr dSph) galaxy, of which 1058 were taken with VLT/FLAMES multi-object spectrograph and 84 were taken with the SAAO Radcliffe 1.9-m telescope grating spectrograph. Spectroscopic membership is confirmed (at >99 per cent confidence) for 592 stars on the basis of their radial velocity, and spectral types are given. Very slow rotation is marginally detected around the galaxy's major axis. We identify five S stars and 23 carbon stars, of which all but four carbon stars are newly determined and all but one (PQ Sgr) are likely Sgr dSph members. We examine the onset of carbon richness in this metal-poor galaxy in the context of stellar models. We compare the stellar death rate (one star per 1000-1700yr) with the known planetary nebula dynamical ages and find that the bulk population produce the observed (carbon-rich) planetary nebulae. We compute average lifetimes of S and carbon stars as 60-250 and 130-500kyr, compared to a total thermal-pulsing asymptotic giant branch lifetime of 530-1330kyr. We conclude by discussing the return of carbon-rich material to the interstellar medium.
- 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/AJ/138/510
- Title:
- Spectral classification of N159/N160 stars
- Short Name:
- J/AJ/138/510
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic study of the N159/N160 massive star-forming region south of 30 Doradus in the Large Magellanic Cloud, classifying a total of 189 stars in the field of the complex. Most of them belong to O and early B spectral classes; we have also found some uncommon and very interesting spectra, including members of the Onfp class, a Be P Cygni star, and some possible multiple systems. Using spectral types as broad indicators of evolutionary stages, we considered the evolutionary status of the region as a whole. We infer that massive stars at different evolutionary stages are present throughout the region, favoring the idea of a common time for the origin of recent star formation in the N159/N160 complex as a whole, while sequential star formation at different rates is probably present in several subregions.
- ID:
- ivo://CDS.VizieR/J/AJ/152/31
- Title:
- Spectral classification of O Vz stars from GOSSS
- Short Name:
- J/AJ/152/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On the basis of the Galactic O Star Spectroscopic Survey (GOSSS), we present a detailed systematic investigation of the O Vz stars. The currently used spectral classification criteria are rediscussed, and the Vz phenomenon is recalibrated through the addition of a quantitative criterion based on the equivalent widths of the HeI{lambda}4471, HeII{lambda}4542, and HeII{lambda}4686 spectral lines. The GOSSS O Vz and O V populations resulting from the newly adopted spectral classification criteria are comparatively analyzed. The locations of the O Vz stars are probed, showing a concentration of the most extreme cases toward the youngest star-forming regions. The occurrence of the Vz spectral peculiarity in a solar-metallicity environment, as predicted by the FASTWIND code, is also investigated, confirming the importance of taking into account several processes for the correct interpretation of the phenomenon.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A9
- Title:
- Spectral classification of stars in NGC 6530
- Short Name:
- J/A+A/546/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mechanisms involved in the star formation process and in particular the duration of the different phases of the cloud contraction are not yet fully understood. Photometric data alone suggest that objects coexist in the young cluster NGC 6530 with ages from ~1Myr up to 10Myrs. We want to derive accurate stellar parameters and, in particular, stellar ages to be able to constrain a possible age spread in the star-forming region NGC6530.
