All B star luminosity classes show a substantial drop in their X-ray emissionbetween spectral type B1 and B2 suggesting an H-R diagram B-star dividing linesomewhat analogous to the one for K giants. This emission appears to be relatedto the bi-stability jump at spectral type B1. But our analyses of B supergiantand giant XMM data revealed several interesting and unexpected results that donot support theoretical predictions. There seems to be a fundamental, unknown,underlying process at work in this spectral region. We now wish to extent ourstudy by requesting XMM EPIC observations of 4 B main sequence stars and 2additional B giants to help us explain the abrupt X-ray changes that areoccurring in this intriguing region of the H-R diagram.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2011-01-31T21:47:00Z/2011-02-27T01:20:32Z
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 Wayne Waldron, 2012, 'The Drop in X-ray Flux at Spectral Type B1: Evidence for a B-Star Dividing Line', 17.56_20190403_1200, European Space Agency, https://doi.org/10.5270/esa-8w2d70y
