TY - JOUR
T1 - HD 45314
T2 - A new γ Cassiopeiae analog among Oe stars
AU - Rauw, G.
AU - Nazé, Y.
AU - Spano, M.
AU - Morel, T.
AU - Ud-Doula, A.
N1 - Funding Information:
We thank the XMM-Newton SOC for their support, Andy Pollock for advice on the interpretation of the EXOSAT data, and Mira Véron (OHP) for accepting our ToO request for observations of HD 45314. The Liège team acknowledges support from the FRS/FNRS and from Belspo through XMM/INTEGRAL and GAIA-DPAC PRODEX contracts. AuD acknowledges support from NASA award NNX12AC72G.
Funding Information:
Based on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA), and observations collected at the European Southern Observatory (La Silla, Chile) and the Observatoire de Haute Provence (France).
PY - 2013
Y1 - 2013
N2 - Context. Oe stars possibly form an extension to higher temperatures of the Be phenomenon, but it is still unclear whether these stars have disks. Aims. X-ray spectra could provide hints for interactions of the star with a putative surrounding disk. Methods. We obtained XMM-Newton observations of two Oe stars, HD 45314 and HD 60848. Spectra and light curves were extracted and analysed. Optical spectra were also obtained to support the X-ray observations. Results. We find that both stars display very different X-ray properties. Whilst HD 60848 has an X-ray spectrum and emission level typical for its spectral type, HD 45314 displays a very hard X-ray emission, dominated by a thermal plasma with kT ∼ 21 keV. Furthermore, HD 45314 displays count rate variations by a factor 2 on timescales of ∼ 103 s and a high log (LX/L bol) =-6.10 ± 0.03. Conclusions. The X-ray properties of HD 45314 indicate that this star is a new member of the class of γ Cas analogs, the first one among the original category of Oe stars.
AB - Context. Oe stars possibly form an extension to higher temperatures of the Be phenomenon, but it is still unclear whether these stars have disks. Aims. X-ray spectra could provide hints for interactions of the star with a putative surrounding disk. Methods. We obtained XMM-Newton observations of two Oe stars, HD 45314 and HD 60848. Spectra and light curves were extracted and analysed. Optical spectra were also obtained to support the X-ray observations. Results. We find that both stars display very different X-ray properties. Whilst HD 60848 has an X-ray spectrum and emission level typical for its spectral type, HD 45314 displays a very hard X-ray emission, dominated by a thermal plasma with kT ∼ 21 keV. Furthermore, HD 45314 displays count rate variations by a factor 2 on timescales of ∼ 103 s and a high log (LX/L bol) =-6.10 ± 0.03. Conclusions. The X-ray properties of HD 45314 indicate that this star is a new member of the class of γ Cas analogs, the first one among the original category of Oe stars.
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U2 - 10.1051/0004-6361/201321774
DO - 10.1051/0004-6361/201321774
M3 - Article
AN - SCOPUS:84880146986
SN - 0004-6361
VL - 555
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - L9
ER -