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- ID:
- ivo://CDS.VizieR/J/AJ/98/1305
- Title:
- Stellar content of NGC 346
- Short Name:
- J/AJ/98/1305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using CCD UBV photometry and spectroscopy, we have investigated the stellar content of NGC 346, the brightest H II region in the SMC. Spectra of 42 stars confirm that 33 are of O type, of which 11 are of type O6.5 or earlier; this is as many early-type O stars as is known in the rest of the SMC. From the spectroscopy and photometry we are able to construct an H-R diagram which is essentially complete down to ~10M_{sun}_. We find an initial mass-function slope {GAMMA}=-1.9, similar to that found for massive stars near the Sun and in the LMC: the presence of six stars in the mass range 40-85M_{sun}_ suggests that the upper-mass limit of the IMF is also not appreciably lower in the SMC than it is in the Galaxy. Our photometry has identified five probable red supergiants of which one was previously known. These stars, plus two B supergiants, are evolved stars of considerably lower mass (15M_{sun}_) than many of the unevolved cluster members. Most of these lower-mass, evolved stars form a spatially distinct subgroup; we believe that NGC 346 thus provides an example of sequential star formation in the SMC. We also have identified a background field population of 5M_{sun}_ stars. We find that the ionizing flux from the hot stars is consistent with the previously known Half nebular luminosity. Finally, we discuss the enigmatic W-R binary HD 5980, which our point-spread-function fitting has identified as a close visual double.
- ID:
- ivo://CDS.VizieR/III/88
- Title:
- Stellar Spectrophotometric Atlas
- Short Name:
- III/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The data were obtained with the Oke multichannel scanner on the 5-meter Hale reflector for purposes of synthetizing galaxy spectra, and the digitized atlas contains normalized spectral energy distributions, computed colors, scan line and continuum indices for 175 selected stars covering the complete ranges of spectral type and luminosity class.
- ID:
- ivo://CDS.VizieR/III/89
- Title:
- Stellar Spectrophotometry
- Short Name:
- III/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a collection of spectrophotometric measurements obtained with rotating grating scanners attached to various telescopes at the Kitt Peak National, Mount Wilson, and Palomar Observatories. The observations were made during the 1970s and early 1980s, both individually and jointly, by S.J. Adelman, D.M. Pyper, S.N. Shore, and R.E. White. All measurements were calibrated with the fluxes of Alpha Lyrae (Vega) as presented by Hayes and Latham (1975ApJ...197..593H). There are 1134 observations concerning 207 individual stars.
- ID:
- ivo://CDS.VizieR/III/208
- Title:
- Sternberg Spectrophotometric Catalog
- Short Name:
- III/208
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains the energy distribution data of 866 stars of different spectral type and luminosity classes in the range 3225-7625{AA} with the step 50{AA}. The observations were made at the Crimean Station of the Sternberg Astronomical Institute during 1970-1984 using spectrophotometer installed at the 48-cm and 60-cm Zeiss reflectors. Standards are Beta Ari, Gamma Ori, Beta Tau, Alfa Leo, Eta UMa, Alfa Lyr, Alfa Aql and Alfa Peg. Energy distribution data in the spectra of standard Stars are based on the calibration of Vega published by Hayes (1985IAUS..111..225H). The average accuracy of the catalogue data is 3.2%. Monochromatic fluxes are in erg/(cm^2^.s.cm*10^-6^). Zero flux is expressed as E-12.
- ID:
- ivo://CDS.VizieR/J/A+AS/110/553
- Title:
- Teff for B, A and F main sequence stars
- Short Name:
- J/A+AS/110/553
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A method of determination of the effective temperature of B, A and F main sequence stars is proposed, using the slope of the continuum between 3200A and 3600A. We have determined the Balmer jump and the effective temperatures for 235 main sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A46
- Title:
- The SUGAR model. Training dataset
- Short Name:
- J/A+A/636/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This analysis develops a new SNe Ia spectral energy distribution (SED) model, called the SUpernova Generator And Reconstructor (SUGAR), which improves the spectral description of SNe Ia, and consequently could improve the distance measurements. This model was constructed from SNe Ia spectral properties and spectrophotometric data from the Nearby Supernova Factory collaboration. In a first step, a principal component analysis-like method was used on spectral features measured at maximum light, which allowed us to extract the intrinsic properties of SNe Ia. Next, the intrinsic properties were used to extract the average extinction curve. Third, an interpolation using Gaussian processes facilitated using data taken at different epochs during the lifetime of an SN Ia and then projecting the data on a fixed time grid. Finally, the three steps were combined to build the SED model as a function of time and wavelength. This is the SUGAR model. The proper way to cite the data can be found at https://snfactory.lbl.gov/snf/data/index.html
- ID:
- ivo://CDS.VizieR/J/A+A/416/669
- Title:
- UBV photometry of HD 6226
- Short Name:
- J/A+A/416/669
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and spectroscopic monitoring of the B star resulted in the finding that this object is a new bright Be star with a clear positive correlation between the brightness and emission-line strength. The emission-line episodes are relatively short and seem to repeat frequently which makes this star an ideal target for studying the causes of the Be phenomenon.
- ID:
- ivo://CDS.VizieR/J/A+A/387/580
- Title:
- UBV photometry of V832 Cyg
- Short Name:
- J/A+A/387/580
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of numerous homogenized UBV photoelectric observations and red spectra of the Be star from several observatories is presented.
120. UniDAM results
- ID:
- ivo://CDS.VizieR/J/A+A/604/A108
- Title:
- UniDAM results
- Short Name:
- J/A+A/604/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic archaeology, the study of the formation and evolution of the Milky Way by reconstructing its past from its current constituents, requires precise and accurate knowledge of stellar parameters for as many stars as possible. To achieve this, a number of large spectroscopic surveys have been undertaken and are still ongoing. So far consortia carrying out the different spectroscopic surveys have used different tools to determine stellar parameters of stars from their derived effective temperatures, surface gravities, and metallicities; the parameters can be combined with photometric, astrometric, interferometric, or asteroseismic information. Here we aim to homogenise the stellar characterisation by applying a unified tool to a large set of publicly available spectrophotometric data. We used spectroscopic data from a variety of large surveys combined with infrared photometry from 2MASS and AllWISE and compared these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages, and distances. We treated PDFs of pre-helium-core burning, helium-core burning, and post helium-core burning solutions as well as different peaks in multimodal PDFs (i.e. each unimodal sub-PDF) of the different evolutionary phases separately. For over 2.5 million stars we report mass, age, and distance estimates for each evolutionary phase and unimodal sub-PDF. We report Gaussian, skewed, Gaussian, truncated Gaussian, modified truncated exponential distribution or truncated Student's t-distribution functions to represent each sub-PDF, allowing us to reconstruct detailed PDFs. Comparisons with stellar parameter estimates from the literature show good agreement within uncertainties. We present UniDAM, the unified tool applicable to spectrophotometric data of different surveys, to obtain a homogenised set of stellar parameters.
