Red giants like Arcturus occupy a region in the X-ray Hertzsprung-RussellDiagram (HRD) known as the coronal graveyard. The physical cause for the sharpdecline of X-ray emission beyond a so-called dividing line that separates X-rayemitting yellow giants from X-ray dark red giants is, despite decades ofresearch, not finally answered. The recent X-ray detection of Arcturus withChandra HRC-I motivates our request to obtain spectral information withXMM-Newton EPIC spectroscopy. An 80 ks exposure is sufficient to detect largeabsorbing column densities that may be expected if severe obscuration by layersabove the giant.s corona cause the decrease in their observed X-ray luminosity.
Instrument
EMOS1, EMOS2, EPN, OM, RGS1, RGS2
Temporal Coverage
2021-01-09T12:35:48Z/2021-01-10T11:55:08Z
Version
18.02_20200221_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 Schneider, 2022, 'Arcturus and the origin of the coronal graveyard', 18.02_20200221_1200, European Space Agency, https://doi.org/10.57780/esa-rvx058h
