Fast-rotation (v sin i of over 20 km/s) is rare among yellow (G2-K1) giants,restricted to tidally-synchronized binary components and the handful of FK Com-class single stars. Such stars have X-ray luminosities and plasma temperaturesamong the highest of known coronal sources. A number of yellow giants with v =100 km/s have been found as companions to hot subdwarfs. These stars have beenspun up by accretion of material from the companion during its AGB phase. Wefind the X-ray emission of the optically-brightest example to be an order ofmagnitude lower than that of FK Com stars. We propose to observe the only twobright comparable systems to discover whether such a surprisingly inefficientmagnetic dynamo is a general outcome of accretive spin-up.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2005-07-13T06:06:21Z/2006-01-19T07:08:40Z
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 Kevin Briggs, 2007, 'Exploring the X-ray emission of G-type giants spun up by accretion', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-mxludos
