On the continua and infrared excess of some bright Be stars

Goraya, P. S.; Tur, N. S.

doi:10.1086/114812

Cited by 3 publications

(3 citation statements)

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“…They identified the components as as B8-7 III and B6-7 IV, suggesting a period of P = 230 yr. In our spectra no companion is obvious, nor would any detectable radial velocity change be expected for such a long period, but it is a newly identified weak Be star.-Hip 25007(AN Col, HD 35165, HR 1772), has been listed as B5 IVnp by Hiltner et al Ve as reported inBhatt et al (1984),Goraya & Tur (1988) classified the star as B3 V, T eff = 21000 K, log g = 4.0, whileFrémat et al (2005) determine T eff = 16543 ± 264 K and log g = 3.850 ± 0.041 and v sin i = 210 ± 10 kms −1 . The discrepancy is probably due to its double BD, filled in by emission, as we conclude the same values as Frémat et al (2005), i.e., a stronger BD when taking into account the doubling.…”

supporting

confidence: 52%

“…-HIP 26368 (HD 37935, HR 1960) is derived as a spectral type B9.5 Ve according to Carrier et al (2002). -HIP 26964 (V731 Tau, HD 37967, HR 1961) is derived as a spectral type of B2.5 Ve as reported in Bhatt et al (1984); Goraya & Tur (1988) classify the star as B3 V, T eff = 21 000 K, log g = 4.0, while Frémat et al (2005) determine T eff = 16 543 ± 264 K and log g = 3.850 ± 0.041 and v sin i = 210 ± 10 km s −1…”

Section: Appendix A: Notes On Individual Be Starsmentioning

confidence: 92%

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Stellar parameters of Be stars observed with X-shooter

Shokry

Rivinius

Mehner

et al. 2018

A&A

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Aims. The X-shooter archive of several thousand telluric standard star spectra was skimmed for Be and Be shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late-type Be stars and the extension of the Be phenomenon into early A stars.Methods. An adapted version of the BCD method is used, using the Balmer discontinuity parameters to determine effective temperature and surface gravity. This method is optimally suited for late B stars. The projected rotational velocity was obtained by profile fitting to the Mg ii lines of the targets, and the spectra were inspected visually for the presence of peculiar features such as the infrared Ca ii triplet or the presence of a double Balmer discontinuity. The Balmer line equivalent widths were measured, but they are only useful for determining the pure emission contribution in a subsample of Be stars owing to uncertainties in determining the photospheric contribution. Results. A total of 78, mostly late-type, Be stars, were identified in the X-shooter telluric standard star archive, out of which 48 had not been reported before. We confirm the general trend that late-type Be stars have more tenuous disks and are less variable than earlytype Be stars. The relatively large number (48) of relatively bright (V > 8.5) additional Be stars casts some doubt on the statistics of late-type Be stars; they are more common than currently thought. The Be/B star fraction may not strongly depend on spectral subtype.

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supporting

confidence: 52%

Section: Appendix A: Notes On Individual Be Starsmentioning

confidence: 92%

Stellar parameters of Be stars observed with X-shooter

Shokry

Rivinius

Mehner

et al. 2018

A&A

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“…In some cases, we were unable to estimate the FWHM due to the stellar lines being merged into the continuum. We therefore approximated the FWHM of the stellar line as the v sin i value for the star, taken from the literature for the following stars; HD 148184 (Krelowski, Schmidt & Snow 1997), HD 52918 (Goraya & Tur 1988), HD 58978 (Mennickent et al 1994), HD 67536 (Grady, Bjorkman & Snow 1987), HD 88661 (Ballereau, Chauville & Zorec 1995), HD 45725 (Slettebak 1982), HD 143275 (Hurwitz & Bowyer 1996), HD 148937 and HD 164794 (Penny 1996). For the Wolf–Rayet stars, we have generally been unable to detect stellar lines with certainty and have not found v sin i values from the literature.…”

Section: Discussionmentioning

confidence: 99%

Early-type stars observed in the ESO UVES Paranal Observatory Project - I. Interstellar Na I UV, Ti II and Ca II K observations

Hunter

Smoker

Keenan

et al. 2006

Monthly Notices of the Royal Astronomical Society

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We present an analysis of interstellar Na i (λair= 3302.37 and 3302.98 Å), Ti ii(λair= 3383.76 Å) and Ca ii K (λair= 3933.66 Å) absorption features for 74 sightlines towards O‐ and B‐type stars in the Galactic disc. The data were obtained from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project, at a spectral resolution of 3.75 km s−1 and with mean signal‐to‐noise ratios per pixel of 260, 300 and 430 for the Na i, Ti ii and Ca ii observations, respectively. Interstellar features were detected in all but one of the Ti ii sightlines and all of the Ca ii sightlines. The dependence of the column density of these three species with distance, height relative to the Galactic plane, H i column density, reddening and depletion relative to the solar abundance has been investigated. We also examine the accuracy of using the Na i column density as an indicator of that for H i. In general, we find similar strong correlations for both Ti and Ca, and weaker correlations for Na. Our results confirm the general belief that Ti and Ca occur in the same regions of the interstellar medium (ISM) and also that the Ti ii/Ca ii ratio is constant over all parameters. We hence conclude that the absorption properties of Ti and Ca are essentially constant under the general ISM conditions of the Galactic disc.

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