梅西耶109
(原标题: Messier 109)
2025-06-27
浏览次数: 16
美丽的棒旋星系梅西耶109是查尔斯·梅西耶著名的明亮星云和星团目录中的第109个条目。你可以在北方大熊座的北斗七星碗下方找到它。事实上，明亮的北斗七星，大熊座伽玛，产生了这个望远镜框架右上角的眩光。M109突出的中央棒状结构使星系看起来像希腊字母“theta”，θ，一个代表角度的常见数学符号。M109在地球的天空中只占很小的角度，大约7角分或0.12度。但这个小角度对应的是银河系大约6000万光年的距离，其直径高达12万光年。现在公认的大熊座星系团中最亮的成员，M109（又名NGC 3992）由尖尖的前景恒星连接。三个小的，模糊的蓝色星系也在现场，被确定为UGC 6969， UGC 6940和UGC 6923（从上到下），可能是较大的棒旋星系Messier 109的卫星星系。
查看原文解释
Big beautiful barred spiral galaxy Messier 109 is the 109th entry in Charles Messier's famous catalog of bright Nebulae and Star Clusters. You can find it just below the Big Dipper's bowl in the northern constellation Ursa Major. In fact, bright dipper star Phecda, Gamma Ursa Majoris, produces the glare at the upper right corner of this telescopic frame. M109's prominent central bar gives the galaxy the appearance of the Greek letter "theta", θ, a common mathematical symbol representing an angle. M109 spans a very small angle in planet Earth's sky though, about 7 arcminutes or 0.12 degrees. But that small angle corresponds to an enormous 120,000 light-year diameter at the galaxy's estimated 60 million light-year distance. The brightest member of the now recognized Ursa Major galaxy cluster, M109 (aka NGC 3992) is joined by spiky foreground stars. Three small, fuzzy bluish galaxies also on the scene, identified (top to bottom) as UGC 6969, UGC 6940 and UGC 6923, are possibly satellite galaxies of the larger barred spiral galaxy Messier 109.
© Robert Eder