Английская Википедия:Crater 2 Dwarf
Шаблон:Short description Шаблон:Sky Шаблон:Infobox galaxy
Crater 2 is a low-surface-brightness dwarf satellite galaxy of the Milky Way,[1] located approximately 380,000 ly from Earth. Its discovery in 2016 revealed significant gaps in astronomers' understanding of galaxies possessing relatively small half-light diameters and suggested the possibility of many undiscovered dwarf galaxies orbiting the Milky Way.[2] Crater 2 was identified in imaging data from the VST ATLAS survey.[2]
The galaxy has a half-light radius of ~Шаблон:Val, making it the fourth largest satellite of the Milky Way.[1] It has an angular size about double of that of the moon.[2][3] Despite the large size, Crater 2 has a surprisingly low surface brightness, implying that it is not very massive.[4] In addition, its velocity dispersion is also low, suggesting it may have formed in a halo of low dark matter density.[5] Alternatively, it may be a result of tidal interactions with it and larger galaxies, such as the Milky Way and the Large Magellanic Cloud,[4] but according to some simulations, this would not explain the relatively large size.[5] This unusually low velocity dispersion was predicted using Modified Newtonian Dynamics, an alternative to the dark matter hypothesis.[6] This prediction was later confirmed by observations.[7]
See also
References
External links
- CDS Aladin previewer: image. Шаблон:Webarchive
- CDS Aladin Lite: image.
Шаблон:Stars of Crater Шаблон:2016 in space Шаблон:Milky Way
