2025年9月18日
Comet C/2025 R2 (SWAN)
Image Credit & Copyright: Team Ciel Austral
Explanation: A new visitor from the outer Solar System, comet C/2025 R2 (SWAN) also known as SWAN25B was only discovered late last week, on September 11. That’s just day before the comet reached perihelion, its closest approach to the Sun. First spotted by Vladimir Bezugly in images from the SWAN instrument on the sun-staring SOHO spacecraft, the comet was surprisingly bright but understandably difficult to see against the Sun’s glare. Still close to the Sun on the sky, the greenish coma and tail of C/2025 R2 (SWAN) are captured in this telescopic snapshot from September 17. Spica, alpha star of the constellation Virgo, shines just beyond the upper left edge of the frame while the comet is about 6.5 light-minutes from planet Earth. Near the western horizon after sunset and slightly easier to see in binoculars from the southern hemisphere, this comet SWAN will pass near Zubenelgenubi, alpha star of Libra, on October 2. C/2025 R2 (SWAN) is scheduled to make its closest approach to our fair planet around October 20.
Tomorrow’s picture: it’s complicated
彗星C/2025 R2 (SWAN)
影像提供与版权: Team Ciel Austral
说明: 来自 太阳系外围的一颗新彗星——C/2025 R2 (SWAN)，又称SWAN25B，于2025年9月11日才被发现，正好是在其通过近日点（距离太阳最近的位置）前一天。这颗彗星最早由弗拉基米尔贝祖格利（Vladimir Bezugly）在太阳观测卫星SOHO搭载的SWAN仪器影像中辨识出。虽然亮度出乎意料地高，但由于位置接近太阳，受到强烈日晕干扰，因此肉眼观测并不容易。在9月17日的望远镜观测影像中，C/2025 R2 (SWAN)呈现出带有绿色的彗发与彗尾。影像左上角边缘可见处女座的主星角宿一（Spica），而当时彗星距离地球仅约6.5光分。这颗彗星位于日落后西方低空位置，从南半球利用双筒望远镜较容易观察。根据预测，它将在10月2日掠过天秤座的主星氐宿一（Zubenelgenubi），并于10月20日前后抵达距离地球最近的位置。
明日的图片: it’s complicated
