ZTF彗星的三重景观

ZTF彗星的三重景观

ByNASA中文

2023年1月31日 A Triple View of Comet ZTF Image Credit & Copyright: Javier Caldera & Miguel Gracia Explanation: Comet ZTF has a distinctive shape. The now bright comet visiting the inner Solar System has been showing not only a common dust tail, ion tail, and green gas coma, but also an uncommonly distinctive antitail. The antitail does not actually lead the comet — it is just that the head of the comet is seen superposed on part of the fanned-out and trailing dust tail. The giant dirty snowball that is Comet C/2022 E3 (ZTF) has now passed its closest to the Sun and tomorrow will pass its closest to the Earth. The main panel of the featured triple image shows how Comet ZTF looked last week…

ZTF彗星的彗尾

ZTF彗星的彗尾

ByNASA中文

2023年1月9日 Tails of Comet ZTF Image Credit & Copyright: Jose Francisco Hernández Explanation: Comet ZTF may become visible to the unaided eye. Discovered early last year, this massive snowball has been brightening as it approaches the Sun and the Earth. C/2022 E3 (ZTF) will be closest to the Sun later this week, at which time it may become visible even without binoculars to northern observers with a clear and dark sky. As they near the Sun, comet brightnesses are notoriously hard to predict, though. In the featured image taken last week in front of a picturesque star field, three blue ion tails extend to the upper right, likely the result of a variable solar wind on ions ejected by the icy comet nucleus. The comet’s…

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…

李奥纳德彗星的超长彗尾

李奥纳德彗星的超长彗尾

ByNASA中文

2021年12月30日 The Further Tail of Comet Leonard Image Credit & Copyright: Daniele Gasparri Explanation: Comet Leonard, brightest comet of 2021, is at the lower left of these two panels captured on December 29 in dark Atacama desert skies. Heading for its perihelion on January 3 Comet Leonard’s visible tail has grown. Stacked exposures with a wide angle lens (also displayed in a reversed B/W scheme for contrast), trace the complicated ion tail for an amazing 60 degrees, with bright Jupiter shining near the horizon at lower right. Material vaporizing from Comet Leonard’s nucleus, a mass of dust, rock, and ices about 1 kilometer across, has produced the long tail of ionized gas fluorescing in the sunlight. Likely flares on the comet’s nucleus and buffeting by…

新智彗星的彗尾

新智彗星的彗尾

ByNASA中文

2021年03月08日 Three Tails of Comet NEOWISE Image Credit & Copyright: Nicolas Lefaudeux Explanation: What created the unusual red tail in Comet NEOWISE? Sodium. A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a surprisingly striated white dust tail and a pleasingly patchy blue ion tail. Some color sensitive images showed an unusual red tail, and analysis showed much of this third tail’s color was emitted by sodium. Gas rich in sodium atoms might have been liberated from Comet NEOWISE’s warming nucleus in early July by bright sunlight, electrically charged by ultraviolet sunlight, and then pushed out by the solar wind. The featured image was captured in mid-July from Brittany, France and shows the real colors. Sodium…

NEOWISE彗星节理分明的彗尾

NEOWISE彗星节理分明的彗尾

ByNASA中文

2020年7月22日 The Structured Tails of Comet NEOWISE Image Credit & Copyright: Zixuan Lin (Beijing Normal U.) Explanation: What is creating the structure in Comet NEOWISE’s tails? Of the two tails evident, the blue ion tail on the left points directly away from the Sun and is pushed out by the flowing and charged solar wind. Structure in the ion tail comes from different rates of expelled blue-glowing ions from the comet’s nucleus, as well as the always complex and continually changing structure of our Sun’s wind. Most unusual for Comet C/2020 F3 (NEOWISE), though, is the wavy structure of its dust tail. This dust tail is pushed out by sunlight, but curves as heavier dust particles are better able to resist this light pressure and…

蒸发中的丘泽彗星

蒸发中的丘泽彗星

ByNASA中文

2020 January 27 Comet CG Evaporates Image Credit & License: ESA, Rosetta, NAVCAM Explanation: Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets is shown in the featured picture, taken in 2015 by ESA’s robotic Rosetta spacecraft that orbited Comet 67P/Churyumov-Gerasimenko (Comet CG) from 2014 to 2016. The picture shows plumes of gas and dust escaping numerous places from Comet CG’s nucleus as it neared the Sun and heated up. The comet has two prominent lobes, the larger one spanning about 4 kilometers, and a smaller 2.5-kilometer lobe connected by a narrow neck. Analyses indicate that evaporation must be taking place…