標題: 南冕座的恆星和塵埃 [打印本頁] 作者: charles 時間: 2009-3-23 11:34 標題: 南冕座的恆星和塵埃
Stars and Dust Across Corona Australis
影像提供: Adam Block, NOAO, AURA, NSF
Explanation:
A cosmic dust cloud sprawls across a rich field of stars in this gorgeous wide field telescopic vista looking toward Corona Australis, the Southern Crown. Probably less than 500 light-years away and effectively blocking light from more distant, background stars in the Milky Way, the densest part of the dust cloud is about 8 light-years long. At its tip (lower left) is a series of lovely blue nebulae cataloged as NGC 6726, 6727, 6729, and IC 4812. Their characteristic blue color is produced as light from hot stars is reflected by the cosmic dust. The tiny but intriguing yellowish arc visible near the blue nebulae marks young variable star R Coronae Australis. Magnificent globular star cluster NGC 6723 is seen here below and left of the nebulae. While NGC 6723 appears to be just outside Corona Australis in the constellation Sagittarius, it actually lies nearly 30,000 light-years away, far beyond the Corona Australis dust cloud.
