The X-ray emission of near-main sequence B stars is poorly understood, and themechanism that generates it is not yet fully identified. It is known that, ingeneral, the main-sequence B-type stars are relatively weak X-ray sources, withX-ray luminosities being only 10^{-9} as a fraction of their bolometricluminosities. The XMM-Newton slew survey revealed that the B2.5V star sigma Sgr(Nunki) is at least 100 times more X-ray luminous compared to an average star ofthis spectral type. We propose a short 5 ks observation to verify the positionand the flux of the X-ray source coinciding with sigma Sgr. If a high X-ray fluxis confirmed, it will have important consequences for our understanding of fastrotating and magnetic B-type stars.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2013-09-22T06:00:13Z/2013-09-22T08:46:53Z
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 Lidia Oskinova, 2014, 'What is NunkiquestionMark', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-bh1n101
