|Title||X-ray Investigation of Origin of Dust Disks around Hot White Dwarfs|
|Author||Prof You-Hua Chu|
|Description||The Helix Nebulas central white dwarf (WD) exhibits hard X-rays and strong mid-IR emission not expected from its photosphere. Analyses of Spitzer photometric and spectral observations suggest the presence of a dust disk at r=50-100 AU. Accretion of this circumstellar dust onto the WDs surface may power the hard X-ray emission. We have found additional 9 WDs with 24 um excesses which may also originate from dust disks. We request EPIC observations of the 4 closest hot WD with mid-IR excesses to help determine whether there is a causal connection between the mid-IR excess and hard X-ray emission. The X-ray luminosities, spectra, and temporal variations will be used to evaluate whether accretion powers the hard X-ray emission.|
|Publication||No observations found associated with the current proposal|
|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, 2013-04-04T00:00:00Z, 067335, 17.56_20190403_1200. https://doi.org/10.5270/esa-7kg9inz|