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1401. Berkeley supernova Ia program. I.
ID:
ivo://CDS.VizieR/J/MNRAS/425/1789
Title:
Berkeley supernova Ia program. I.
Short Name:
J/MNRAS/425/1789
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this first paper in a series, we present 1298 low-redshift (z<~0.2) optical spectra of 582 Type Ia supernovae (SNe Ia) observed from 1989 to 2008 as part of the Berkeley Supernova Ia Program (BSNIP). 584 spectra of 199 SNe Ia have well-calibrated light curves with measured distance moduli, and many of the spectra have been corrected for host-galaxy contamination. Most of the data were obtained using the Kast double spectrograph mounted on the Shane 3m telescope at Lick Observatory and have a typical wavelength range of 3300-10400{AA}, roughly twice as wide as spectra from most previously published data sets. We present our observing and reduction procedures, and we describe the resulting SN Database, which will be an online, public, searchable data base containing all of our fully reduced spectra and companion photometry. In addition, we discuss our spectral classification scheme (using the SuperNova IDentification code, SNID; Blondin & Tonry, 2007ApJ...666.1024B), utilizing our newly constructed set of SNID spectral templates.
1402. Berkeley supernova Ia program. II.
ID:
ivo://CDS.VizieR/J/MNRAS/425/1819
Title:
Berkeley supernova Ia program. II.
Short Name:
J/MNRAS/425/1819
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this second paper in a series, we present measurements of spectral features of 432 low-redshift (z<0.1) optical spectra of 261 Type Ia supernovae (SNe Ia) within 20d of maximum brightness. The data were obtained from 1989 to the end of 2008 as part of the Berkeley Supernova Ia Program (BSNIP) and are presented in BSNIP I by Silverman et al. (J/MNRAS/425/1789). We describe in detail our method of automated, robust spectral feature definition and measurement which expands upon similar previous studies. Using this procedure, we attempt to measure expansion velocities, pseudo-equivalent widths (pEWs), spectral feature depths and fluxes at the centre and endpoints of each of nine major spectral feature complexes.
1403. Berkeley 51 UBV photometry
ID:
ivo://CDS.VizieR/J/MNRAS/477/2976
Title:
Berkeley 51 UBV photometry
Short Name:
J/MNRAS/477/2976
Date:
02 Mar 2022 00:35:30
Publisher:
CDS
Description:
The heavily obscured open cluster Berkeley 51 shows characteristics typical of young massive clusters, even though the few previous studies have suggested older ages. We combine optical (UBV) and 2MASS photometry of the cluster field with multi-object and long-slit optical spectroscopy for a large sample of stars. We apply classical photometric analysis techniques to determine the reddening to the cluster, and then derive cluster parameters via isochrone fitting. We find a large population of B-type stars, with a main-sequence turn-off at B3 V, as well as a large number of supergiants with spectral types ranging from F to M. We use intermediate-resolution spectra of the evolved cool stars to derive their stellar parameters and find an essentially solar iron abundance. Under the plausible assumption that our photometry reaches stars still close to the zero-age main sequence, the cluster is located at d=~5.5kpc and has an age of ~60Ma, though a slightly younger and more distant cluster cannot be ruled out. Despite the apparent good fit of isochrones, evolved stars seem to reside in positions of the colour-magnitude diagram far away from the locations where stellar tracks predict helium burning to occur. Of particular interest is the presence of four yellow supergiants, two on the ascending branch and two others close to or inside the instability strip.
1404. BeSOS Be stars stellar parameters
ID:
ivo://CDS.VizieR/J/MNRAS/474/5287
Title:
BeSOS Be stars stellar parameters
Short Name:
J/MNRAS/474/5287
Date:
07 Dec 2021 13:16:10
Publisher:
CDS
Description:
The Be phenomenon is present in about 20 per cent of B-type stars. Be stars show variability on a broad range of time-scales, which in most cases is related to the presence of a circumstellar disc of variable size and structure. For this reason, a time-resolved survey is highly desirable in order to understand the mechanisms of disc formation, which are still poorly understood. In addition, a complete observational sample would improve the statistical significance of the study of stellar and disc parameters. The 'Be Stars Observation Survey' (BeSOS) is a survey containing reduced spectra obtained using the Pontifica Universidad Catolica High Echelle Resolution Optical Spectrograph (PUCHEROS) with a spectral resolution of 17000 in the range 4260-7300{AA}. BeSOS's main objective is to offer consistent spectroscopic and time-resolved data obtained with one instrument. The user can download or plot the data and obtain stellar parameters directly from the website. We also provide a star-by-star analysis based on photometric, spectroscopic and interferometric data, as well as general information about the whole BeSOS sample. Recently, BeSOS led to the discovery of a new Be star HD 42167 and facilitated study of the V/R variation of HD 35165 and HD 120324, the steady disc of HD 110335 and the Be shell status of HD 127972. Optical spectra used in this work, as well as the stellar parameters derived, are available online at http://besos.ifa.uv.cl.
1405. Be star candidates in Magellanic Clouds
ID:
ivo://CDS.VizieR/J/MNRAS/469/4175
Title:
Be star candidates in Magellanic Clouds
Short Name:
J/MNRAS/469/4175
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a proper motion investigation of a sample of Be star candidates towards the Magellanic Clouds, which has resulted in the identification of separate populations, in the Galactic foreground and in the Magellanic background. Be stars are broadly speaking B-type stars that have shown emission lines in their spectra. In this work, we studied a sample of 2446 and 1019 Be star candidates towards the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively, taken from the literature and proposed as possible Be stars due to their variability behaviour in the OGLE-II I band. JHKs magnitudes from the InfraRed Survey Facility catalogue and proper motions from the Southern Proper Motion 4 catalogue were obtained for 1188 and 619 LMC and SMC Be stars candidates, respectively. Colour-colour and vector-point diagrams were used to identify different populations amongst the Be star candidates. In the LMC sample, two populations with distinctive infrared colours and kinematics were found, the bluer sample is consistent with being in the LMC and the redder one with belonging to the Milky Way disc. This settles the nature of the redder sample that had been described in previous publications as a possible unknown subclass of stars amongst the Be candidates in the LMC. In the SMC sample, a similar but less evident result was obtained, since this apparent unknown subclass was not seen in this galaxy. We confirm that in the selection of Be stars by their variability, although generally successful, there is a higher risk of contamination by Milky Way objects towards redder B-V and V-I colours.
1406. Be star rotational velocities distribution
ID:
ivo://CDS.VizieR/J/A+A/595/A132
Title:
Be star rotational velocities distribution
Short Name:
J/A+A/595/A132
Date:
21 Oct 2021
Publisher:
CDS
Description:
Among intermediate-mass and massive stars, Be stars are the fastest rotators in the main sequence (MS) and, as such, these stars are a cornerstone to validate models of structure and evolution of rotating stars. Several phenomena, however, induce under- or overestimations either of their apparent Vsini, or true velocity V. In the present contribution we aim at obtaining distributions of true rotational velocities corrected for systematic effects induced by the rapid rotation itself, macroturbulent velocities, and binarity. We study a set of 233 Be stars by assuming they have inclination angles distributed at random. We critically discuss the methods of Cranmer and Lucy-Richardson, which enable us to transform a distribution of projected velocities into another distribution of true rotational velocities, where the gravitational darkening effect on the Vsini parameter is considered in different ways. We conclude that iterative algorithm by Lucy-Richardson responds at best to the purposes of the present work, but it requires a thorough determination of the stellar fundamental parameters. We conclude that once the mode of ratios of the true velocities of Be stars attains the value V/Vc~0.77 in the main-sequence (MS) evolutionary phase, it remains unchanged up to the end of the MS lifespan. The statistical corrections found on the distribution of ratios V/Vc for overestimations of Vsini due to macroturbulent motions and binarity, produce a shift of this distribution toward lower values of V/Vc when Be stars in all MS evolutionary stages are considered together. The mode of the final distribution obtained is at V/Vc~0.65. This distribution has a nearly symmetric distribution and shows that the Be phenomenon is characterized by a wide range of true velocity ratios 0.3<V/Vc<0.95. It thus suggests that the probability that Be stars are critical rotators is extremely low. The corrections attempted in the present work represent an initial step to infer indications about the nature of the Be-star surface rotation that will be studied in the second paper of this series.
1407. Be Stars Catalog
ID:
ivo://nasa.heasarc/bestars
Title:
Be Stars Catalog
Short Name:
Be
Date:
21 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
The BESTARS database tables contains a compilation of data concerning stars of type Be. For the purposes of this compilation, a Be star is defined as a non-supergiant B star which showed emission in one Balmer line at least once. Stars without published MK spectral types have been excluded, except for 132 stars from Bidelman and MacConnell (1973), who used the above definition but included no spectral types. There are 1,159 stars included in this list. This is a service provided by NASA HEASARC .
1408. Be stars in LAMOST DR1
ID:
ivo://CDS.VizieR/J/other/RAA/15.1325
Title:
Be stars in LAMOST DR1
Short Name:
J/other/RAA/15.1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on searching for Classical B-type emission-line (CBe) stars in the first data release of the Large Sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST; also called the Guo Shou Jing Telescope). A total of 192 objects (including 12 previously known CBes) were identified as CBe candidates with prominent HeI {lambda}4387, HeI {lambda}4471 and MgII {lambda}4481 absorption lines, as well as H{beta} {lambda}4861 and H{alpha} {lambda}6563 emission lines. These candidates significantly increase the currently known sample of CBes by about 8%. Most of the CBe candidates are distributed near the Galactic Anti-Center due to the observing strategy used for LAMOST. Only two CBes are in star clusters. These two CBes have ages of 15.8 and 398Myr, respectively.
1409. Be stars in MC star clusters NIR properties
ID:
ivo://CDS.VizieR/J/other/NewA/56.28
Title:
Be stars in MC star clusters NIR properties
Short Name:
J/other/NewA/56.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Magellanic Clouds are the nearby galaxies which are ideal to study the properties of metal poor stellar population. In this study, we explore the near-IR properties of optically identified classical Be stars in 19 star clusters in the Magellanic Clouds. From an optically identified sample of 835 Be stars we obtained the J, H, K magnitudes of 389 stars from the IRSF MCPS catalog. Among these, 247 stars (36.4%) are found in 9 clusters in the Large Magellanic Cloud and 142 stars (55.5%) in 10 clusters in the Small Magellanic Cloud. After correcting for reddening, we studied their NIR properties in the (H-K)_0_ vs (J-H)_0_ diagram. We identified 14 stars with abnormally large near IR excesses, which were removed from the analysis, there by restricting our study to 355 classical Be stars. We propose an extended area in the near-IR (H-K)_0_ vs (J-H)_0_ diagram as the diagnostic location of Classical Be stars in the Magellanic Clouds. We identified 14 stars to have near-IR excess, higher than those seen in classical Be stars. From the analysis based on spectral energy distribution and luminosity estimate, we found that 8 candidate Be stars may be Herbig Ae/Be stars. We identified a new sample of 6 sgB[e] stars, which when added to the sparse existing sample of 15 sgB[e] stars in the Magellanic Clouds can provide insight to understand the evolutionary link between sgB[e] stars and Luminous Blue variables.
1410. Be stars in MC young clusters
ID:
ivo://CDS.VizieR/J/A+AS/134/489
Title:
Be stars in MC young clusters
Short Name:
J/A+AS/134/489
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a search for Be stars in six fields centered on the young clusters NGC 330 and NGC 346 in the SMC, and NGC 1818, NGC 1948, NGC 2004 and NGC 2100 in the LMC. Be stars were identified by differencing R band and narrow-band H{alpha} CCD images. Our comparatively large images provide substantial Be star populations both within the clusters and in their surrounding fields. Magnitudes, positions and finding charts are given for the 224 Be stars found. The fraction of Be stars to normal B stars within each cluster is found to vary significantly although the average ratio is similar to the average Be to B star ratio found in the Galaxy. In some clusters, the Be star population is weighted to magnitudes near the main sequence turn-off. The Be stars are redder in V-I than normal main-sequence stars of similar magnitude and the redness increases with increasing H{alpha} emission strength.

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