37星团

37星团

The 37 Cluster
Image Credit & Copyright: Sergio Eguivar

Explanation: For the mostly harmless denizens of planet Earth, the brighter stars of open cluster NGC 2169 seem to form a cosmic 37. Did you expect 42? From our perspective, the improbable numerical asterism appears solely by chance. It lies at an estimated distance of 3,300 light-years toward the constellation Orion. As far as galactic or open star clusters go, NGC 2169 is a small one, spanning about 7 light-years. Formed at the same time from the same cloud of dust and gas, the stars of NGC 2169 are only about 11 million years old. Such clusters are expected to disperse over time as they encounter other stars, interstellar clouds, and experience gravitational tides while hitchhiking through the galaxy. Over four billion years ago, our own Sun was likely formed in a similar open cluster of stars.

Gallery: Earth Aurora from Solar Active Region 3664

Tomorrow’s picture: at the Sun’s edge

37星团
影像提供与版权: Sergio Eguivar

说明: 对地球上众多善良的住民来说，疏散星团NGC 2169的亮星看似聚成了宇宙级的37字样。你会预期是42吗？依我们来看，这种难以置信的数字星官，其出现看似只是偶然。此星团位于猎户座方向，与地球的估计距离约为3,600光年。就银河或疏散星团而言，NGC 2169是个跨度约7光年的小星团。NGC 2169里稚龄约只有800万年的恒星，咸信是形成于相同的尘埃和气体云里。随着它们在银河系里旅行，遇到了其他的恒星、星际星云、及受到重力潮汐的作用，这种星团预期会随着时间的推移而逐渐崩解。在40多亿年前，我们的太阳可能也是诞生于类似的疏散星团里。

图片集: 来自太阳活跃区3664的全球极光

明日的图片: at the Sun’s edge