Supersoft X-ray source: Difference between revisions

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A '''luminous supersoft X-ray source''' (SSXS, or SSS) is an [[Astronomy|astronomical]] source that emits only low energy (i.e., soft) [[X-rays]]. Soft X-rays have energies in the 0.09 to 2.5 [[keV]] range, whereas hard X-rays are in the 1–20 keV range.<ref name=Supersoft>{{ cite web |title=Supersoft X-Ray Sources |url=http://library.thinkquest.org/27930/supersoft.htm |url-status=dead |archiveurl=https://web.archive.org/web/20080607122110/http://library.thinkquest.org/27930/supersoft.htm |archivedate=2008-06-07 }}</ref> SSSs emit few or no photons with energies above 1 keV, and most have [[effective temperaturestemperature]] below 100 eV. This means that the radiation they emit is highly ionizing and is readily absorbed by the interstellar medium. Most SSSs within our own galaxy are hidden by interstellar absorption in the galactic disk.<ref name=White/> They are readily evident in external galaxies, with ~10 found in the Magellanic Clouds and at least 15 seen in M31.<ref name=White/>

As of early 2005, more than 100 SSSs have been reported in ~20 external galaxies, the [[Large Magellanic Cloud]] (LMC), [[Small Magellanic Cloud]] (SMC), and the [[Milky Way]] (MW).<ref name=Kahabka/> Those with luminosities below ~3 x 10³⁸ [[erg]]/s are consistent with steady [[Stellar surface fusion|nuclear burning]] in accreting [[white dwarf]]s (WD)s or post-novae.<ref name=Kahabka/> There are a few SSS with luminosities ≥10³⁹ erg/s.<ref name=Kahabka/>