Guest Observer Facilities & Science Centers Select One AGILE ASCA BeppoSAX COBE CGRO Chandra EUVE Fermi (formerly GLAST) GALEX HETE-2 INTEGRAL ROSAT RXTE Suzaku Swift WMAP XMM-Newton NASA Archives Select One ADS AstroGravS EOSDIS HORIZONS IRSA LAMBDA MAST Michelson NED NSSDC NStED PDS SDAC SPDF Spitzer Science Center HEASARC Tip: View all tips Last Update: August 26th, 2003 What kinds of cosmic objects have been detected as X-ray emitters? In our own Solar system? In our Milky Way Galaxy? In the entire Universe? The short answer to this is: a large number of them! In our own Solar System, for example, the Sun is the strongest emitter of X-rays. It was first detected as an X-ray source as long ago as 1948, and it emits X-rays with a typical luminosity or power output of 1027 erg s-1 or 1020 Watts. Other objects in our Solar System which have been detected as X-ray emitters include the Moon, the planets Jupiter, Saturn, Venus, and Mars, two or three of the moons of Jupiter, and the Io Plasma Torus, as well as a number of comets. In our Galaxy, the brightest X-ray emitters (X-ray luminosities up to 1038 erg s-1 which are 100 billion times brighter than the `Quiet' Sun) are the X-ray binaries (close binary systems in which one member is a neutron star or black hole that is accreting matter from the other [normal] companion star) and supernova remnants. Almost every type of star from massive OB stars to low-mass M dwarf stars, single white dwarf and neutron stars, and even some sub-stellar mass brown dwarfs, have been detected as X-ray sources, as have some types of extended objects, such as planetary nebulae, H II regions, the Local Bubble, etc. The only types of stars that have not been confirmed as intrinsic X-ray sources are the A-type stars, cool white dwarf stars, and red (M-type) giant and supergiant stars. The integrated X-ray luminosity of our entire Galaxy is estimated to be about 3 x 1039 erg s-1. In the entire Universe, the most luminous X-ray sources are rich clusters of galaxies and active galactic nuclei (AGN), both of which classes can reach X-ray luminosities of as high as 1045 erg s-1. Typical `normal' galaxies, on the other hand, have much lower X-ray luminosities lieing in the range from 1038 erg s-1 to 3 x 1042 erg s-1. Web page author and maintainer: Stephen A. Drake HEASARC Home | Observatories | Archive | Calibration | Software | Tools | Students/Teachers/Public Last modified: Tuesday, 27-Jun-2006 14:53:25 EDT Science Mission Directorate Universe Division Beyond Einstein | Origins FAQ/Comments/Feedback Education Resources Find helper applications like Adobe Acrobat A service of the Astrophysics Science Division at NASA/ GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory (SAO) HEASARC Director: Dr. Alan P. Smale HEASARC Associate Director: Dr. Roger Brissenden Responsible NASA Official: Phil Newman Web Curator: Karen Smale Privacy Policy and Important Notices.