Chandra Release - July 27, 2005

Visual Description: Neon Abundance in Nearby Stars

In this graphic, an Chandra X-ray Observatory spectrum (that is, a plot of energy versus different wavelengths) is set atop an illustration that features the star II Pegasi.  The illustration shows a bright Sun-like star on a black background, and a cut out of the Sun-like star shows its interior structure and convection lines near the rim.   At bottom right the Chandra spectrum shows two main blue-green peaks. Chandra measurements of the amount of neon in II Pegasi and 20 other nearby Sun-like stars may provide a better understanding of our nearest star, the Sun. The neon abundances in the outer atmospheres, or coronas, of the 21 stars are remarkably similar, and almost three times larger than estimates of solar abundances.  Neon plays an important role in regulating the rate at which energy flows from the center to the surface of the Sun. If the observed larger abundance of neon applies to the Sun, theoretical models for its interior structure can be brought back into agreement with the observations.