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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.)

A HARD AND VARIABLE X-RAY EMISSION FROM THE MASSIVE EMISSION-LINE STAR HD 157832

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Author(s):
Lopes de Oliveira, R. [1] ; Motch, C. [2]
Total Authors: 2
Affiliation:
[1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Strasbourg, CNRS, UMR 7550, Astron Observ, F-67000 Strasbourg - France
Total Affiliations: 2
Document type: Journal article
Source: Astrophysical Journal Letters; v. 731, n. 1 APR 10 2011.
Web of Science Citations: 6
Abstract

We report the discovery with XMM-Newton of a hard-thermal (T similar to 130 MK) and variable X-ray emission from the Be star HD 157832, a new member of the puzzling class of gamma-Cas-like Be/X-ray systems. Recent optical spectroscopy reveals the presence of a large/dense circumstellar disk seen at intermediate/high inclination. With a B1.5V spectral type, HD 157832 is the coolest gamma-Cas analog known. In addition, its non-detection in the ROSAT all-sky survey shows that its average soft X-ray luminosity varied by a factor larger than similar to 3 over a time interval of 14 yr. These two remarkable features, ``low{''} effective temperature, and likely high X-ray variability turn HD 157832 into a promising object for understanding the origin of the unusually high-temperature X-ray emission in these systems. (AU)

FAPESP's process: 10/08341-3 - High energy astrophysics
Grantee:Raimundo Lopes de Oliveira Filho
Support type: Scholarships in Brazil - Young Researchers
FAPESP's process: 09/06295-7 - High energy astrophysics
Grantee:Raimundo Lopes de Oliveira Filho
Support type: Research Grants - Young Investigators Grants