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Full-Text Articles in Astrophysics and Astronomy
Excess Mid-Infrared Flux: An Indicator Of Mass Loss In Cepheids?, Edward G. Schmidt
Excess Mid-Infrared Flux: An Indicator Of Mass Loss In Cepheids?, Edward G. Schmidt
Edward Schmidt Publications
Spectral energy distributions for 132 classical and type II Cepheids were searched for evidence of excess flux above the photospheric level in the mid-infrared. Eight of them were found to have unambiguously strong excess emission while a further 13 showed evidence of weak emission. The presence of emission appears to be unrelated to either the pulsational amplitude or the effective temperature while strong emission is limited to stars with periods longer than 11 days, with a single exception. For the stars with strong emission we attempted to fit the energy distribution with a stellar wind model. No acceptable fit could …
New Multiwavelength Observations Of The Of?P Star Cpd -28◦ 2561., S. Hubrig, M. Schöller, A. Kholtygin, H. Tsumura, A. Hoshino, S. Kitamoto, L. Oskinova, Richard Ignace, H. Todt, I. Ilyin
New Multiwavelength Observations Of The Of?P Star Cpd -28◦ 2561., S. Hubrig, M. Schöller, A. Kholtygin, H. Tsumura, A. Hoshino, S. Kitamoto, L. Oskinova, Richard Ignace, H. Todt, I. Ilyin
ETSU Faculty Works
A rather strong mean longitudinal magnetic field of the order of a few hundred gauss was detected a few years ago in the Of?p star CPD −28° 2561 using FORS2 (FOcal Reducer low dispersion Spectrograph 2) low-resolution spectropolarimetric observations. In this work, we present additional low-resolution spectropolarimetric observations obtained during several weeks in 2013 December using FORS 2 mounted at the 8-m Antu telescope of the Very Large Telescope (VLT). These observations cover a little less than half of the stellar rotation period of 73.41 d mentioned in the literature. The behaviour of the mean longitudinal magnetic field is consistent …
On X-Ray Pulsations In Beta Cephei-Type Variables, L. Oskinova, H. Todt, D. Huenemoerder, S. Hubrig, Richard Ignace, W.-R. Hamann, L. Balona
On X-Ray Pulsations In Beta Cephei-Type Variables, L. Oskinova, H. Todt, D. Huenemoerder, S. Hubrig, Richard Ignace, W.-R. Hamann, L. Balona
ETSU Faculty Works
Beta Cephei-type variables are early B-type stars that are characterized by oscillations observable in their optical light curves. At least one Beta Cep-variable also shows periodic variability in X-rays. Here we study the X-ray light curves in a sample of beta Cep-variables to investigate how common X-ray pulsations are for this type of stars. We searched the Chandra and XMM-Newton X-ray archives and selected stars that were observed by these telescopes for at least three optical pulsational periods. We retrieved and analyzed the X-ray data for kappa Sco, beta Cru, and alpha Vir. The X-ray light curves of these objects …