The origin of the hard X-ray spectrum emitted by Gamma-Cas remains a puzzle.Both a white dwarf accreting from the Be star circumstellar disc or magneticinteraction between the photosphere and the disc can explain the unusually hardX-ray emission. The recent discovery of several new G-Cas analogs offers newopportunities to address this problem. XMM-Newton observations of two G-Casanalogs, HD161103 and HD119682 revealed evidences of periodic modulations of theX-ray flux apparently stronger than in G-Cas itself. We propose to re-observethese two sources in order to confirm or not the stability of the period.Establishing the presence of a stable pulsation in any of these G-Cas analogswould be a major step forward in our understanding of the whole class.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2009-03-06T10:55:31Z/2009-03-07T02:50:01Z
Version
17.56_20190403_1200
Mission Description
The European Space Agencys (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESAs second cornerstone of the Horizon 2000 Science Programme. It carries 3 high throughput X-ray telescopes with an unprecedented effective area, and an optical monitor, the first flown on a X-ray observatory. The large collecting area and ability to make long uninterrupted exposures provide highly sensitive observations. Since Earths atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself. Observing time on XMM-Newton is being made available to the scientific community, applying for observational periods on a competitive basis.
European Space Agency, Dr Christian Motch, 2010, 'A search for a spinning white dwarf companion in Gamma-Cas-analogs', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-k0029hp
