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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Stellar parameters of Be stars observed with X-shooter

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Shokry, A. [1, 2, 3] ; Rivinius, Th. [2] ; Mehner, A. [2] ; Martayan, C. [2] ; Hummel, W. [4] ; Townsend, R. H. D. [5] ; Merand, A. [2] ; Mota, B. [6] ; Faes, D. M. [6] ; Hamdy, M. A. [1] ; Beheary, M. M. [7] ; Gadallah, K. A. K. [7] ; Abo-Elazm, M. S. [1]
Total Authors: 13
[1] NRIAG, Dept Astron, Cairo 11421 - Egypt
[2] ESO European Org Astron Res Southern Hemisphere, Casilla 19001, Santiago - Chile
[3] ASRT, STDF, Kottamia Ctr Sci Excellence Astron & Space Sci KC, Cairo - Egypt
[4] ESO European Org Astron Res Southern Hemisphere, Karl Schwarzschild Str 2, Garchingnwt - Germany
[5] Univ Wisconsin, Dept Astron, Madison, WI 53706 - USA
[6] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil
[7] Al Azhar Univ, Fac Sci, Astron & Meteorol Dept, Cairo - Egypt
Total Affiliations: 7
Document type: Journal article
Source: Astronomy & Astrophysics; v. 609, JAN 25 2018.
Web of Science Citations: 3

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 early-type 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. (AU)

FAPESP's process: 16/16844-1 - Systems Engineering for GMACS: GMT AT-13 Project
Grantee:Daniel Moser Faes
Support type: Scholarships in Brazil - Post-Doctorate