西村彗星

西村彗星

ByNASA中文

2023年8月21日 Introducing Comet Nishimura Credit & Copyright: Dan Bartlett Explanation: Will Comet Nishimura become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it currently seems like a good bet. The comet was discovered only ten days ago by Hideo Nishimura during 30-second exposures with a standard digital camera. Since then, C/2023 P1 Nishimura has increased in brightness and its path across the inner Solar System determined. As the comet dives toward the Sun, it will surely continue to intensify and possibly become a naked-eye object in early September. A problem is that the comet will also be angularly near the Sun, so it will only be possible to see it near sunset or sunrise. The comet…

彗星2022 E3 (ZTF)

彗星2022 E3 (ZTF)

ByNASA中文

2022年12月24日 Comet 2022 E3 (ZTF) Image Credit & Copyright: Dan Bartlett Explanation: Comet C/2022 E3 (ZTF) was discovered by astronomers using the wide-field survey camera at the Zwicky Transient Facility this year in early March. Since then the new long-period comet has brightened substantially and is now sweeping across the northern constellation Corona Borealis in predawn skies. It’s still too dim to see without a telescope though. But this fine telescopic image from December 19 does show the comet’s brighter greenish coma, short broad dust tail, and long faint ion tail stretching across a 2.5 degree wide field-of-view. On a voyage through the inner Solar System comet 2022 E3 will be at perihelion, its closest to the Sun, in the new year on January 12…

摄于澳洲的李奥纳德彗星特写

摄于澳洲的李奥纳德彗星特写

ByNASA中文

2022年1月12日 Comet Leonard Closeup from Australia Image Credit & Copyright: Blake Estes (itelescope.net) Explanation: What does Comet Leonard look like up close? Although we can’t go there, imaging the comet’s coma and inner tails through a small telescope gives us a good idea. As the name implies, the ion tail is made of ionized gas — gas energized by ultraviolet light from the Sun and pushed outward by the solar wind. The solar wind is quite structured and sculpted by the Sun’s complex and ever changing magnetic field. The effect of the variable solar wind combined with different gas jets venting from the comet’s nucleus accounts for the tail’s complex structure. Following the wind, structure in Comet Leonard’s tail can be seen to move outward…

伦纳德彗星

伦纳德彗星

ByNASA中文

2021年11月21日 Introducing Comet Leonard Image Credit & Copyright: Dan Bartlett Explanation: Here comes Comet Leonard. Comet C/2021 A1 (Leonard) was discovered as a faint smudge in January 2021 when it was out past Mars — but its orbit will take the giant shedding ice-ball into the inner Solar System, passing near both Earth and Venus in December before it swoops around the Sun in early January 2022. Although comets are notoriously hard to predict, some estimations have Comet Leonard brightening to become visible to the unaided eye in December. Comet Leonard was captured just over a week ago already sporting a green-tinged coma and an extended dust tail. The featured picture was composed from 62 images taken through a moderate-sized telescope — one set of…