|Title||Can accretion shocks of very-low-mass stars produce X-ray emission?|
|Author||Dr Costanza Argiroffi|
|Description||The accretion process in young stars produces intense X-rays. Very-low-mass stars (VLMS) cannot have post-shock hotter than 2MK, preventing any X-ray emission. Nonetheless 2 accreting VLMS showed X-rays from accretion shocks. To confirm or reject this finding we propose to observe 3 other accreting VLMS with XMM-EPIC (10ks for each target) to measure the plasma temperature, and hence distinguish between X-rays due to corona or to accretion. Accretion-driven X-rays in VLMS would indicate post-shocks hotter than 2MK, possible only if accretion velocity is higher than free fall velocity. Checking the hypothesis of accretion-driven X-rays in VLMS is fundamental to test whether another mechanism, other than gravity, accelerates accreting material.|
|Publication||Serendipitous UV source catalogues for 10 years of XMM and 5 years of Swift . Yershov, V. N., . Ap&SS . 354-97 . 2014 . 2014Ap&SS.354...97Y ,
The Million Optical - Radio-X-ray Associations (MORX) Catalogue . Flesch, Eric W., . PASA . 33-52 . 2016 . 2016PASA...33...52F ,
|Instrument||EMOS1, EMOS2, EPN, OM, RGS1, RGS2|
|Mission Description||The European Space Agency's (ESA) X-ray Multi-Mirror Mission (XMM-Newton) was launched by an Ariane 504 on December 10th 1999. XMM-Newton is ESA's 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 Earth's 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.
|Publisher And Registrant||European Space Agency|
|Credit Guidelines||European Space Agency, 2014-01-29T00:00:00Z, 069477, 17.56_20190403_1200. https://doi.org/10.5270/esa-z6u5ofg|