# M85-HCC1

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Ultracompact dwarf galaxy that is the densest galaxy known

M85-HCC1 Images of two ultracompact dwarf galaxies. M59-UCD3 is in the inset to the left, while M85-HCC1 is in the inset to the right. Observation data (J2000 epoch) Constellation Coma Berenices Right ascension 12h 25m 22.842s[1] Declination +18° 10′ 53.67″[1] Heliocentric radial velocity 658 ± 4[2] Apparent magnitude (V) 18.80 ± 0.03[2] Absolute magnitude (V) −12.55 ± 0.07[2] Characteristics Mass (1.2±0.1)×107[2] M☉ Half-light radius (physical) 1.85 ± 0.9 pc[2] Other designations 2MASS J12252287+1810539, SDSS J122522.84+181053.6[1]

**M85-HCC1** is an ultracompact [dwarf galaxy](/source/Dwarf_galaxy) with a star density 1,000,000 times that of the solar neighbourhood,[3][2] lying near the galaxy [Messier 85](/source/Messier_85). As of 2015[\[update\]](https://en.wikipedia.org/w/index.php?title=M85-HCC1&action=edit), it is the densest galaxy known.[4]

## See also

- [List of most massive galaxies](/source/List_of_galaxies#Galaxies_by_mass_and_density)

## References

1. ^ [***a***](#cite_ref-SIMBAD_1-0) [***b***](#cite_ref-SIMBAD_1-1) [***c***](#cite_ref-SIMBAD_1-2) ["2MASS J12252287+1810539"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=2MASS+J12252287%2B1810539). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 6 May 2018.

1. ^ [***a***](#cite_ref-Sandoval_2-0) [***b***](#cite_ref-Sandoval_2-1) [***c***](#cite_ref-Sandoval_2-2) [***d***](#cite_ref-Sandoval_2-3) [***e***](#cite_ref-Sandoval_2-4) [***f***](#cite_ref-Sandoval_2-5) Michael A. Sandoval; Richard P. Vo; Aaron J. Romanowsky (2015). "Hiding in plain sight: record-breaking compact stellar systems in the Sloan Digital Sky Survey". *Astrophysical Journal Letters*. **808** (1): L32. [arXiv](/source/ArXiv_(identifier)):[1506.08828](https://arxiv.org/abs/1506.08828). [Bibcode](/source/Bibcode_(identifier)):[2015ApJ...808L..32S](https://ui.adsabs.harvard.edu/abs/2015ApJ...808L..32S). [doi](/source/Doi_(identifier)):[10.1088/2041-8205/808/1/l32](https://doi.org/10.1088%2F2041-8205%2F808%2F1%2Fl32). [S2CID](/source/S2CID_(identifier)) [55254708](https://api.semanticscholar.org/CorpusID:55254708).

1. **[^](#cite_ref-3)** ["Hiding in plain sight: Undergraduates discover the densest galaxies known"](http://phys.org/news/2015-07-plain-sight-undergraduates-densest-galaxies.html). *physOrg*. 27 July 2015. Retrieved 29 July 2015.

1. **[^](#cite_ref-SpaceDaily-2015-07-29_4-0)** ["Undergraduates discover the densest galaxies known"](http://www.spacedaily.com/reports/Undergraduates_discover_the_densest_galaxies_known_999.html). Space Daily. 29 July 2015.

## See also

- [M59-UCD3](/source/M59-UCD3) (second-densest galaxy known, as of 2015)

- [M60-UCD1](/source/M60-UCD1) (another dense galaxy)

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Adapted from the Wikipedia article [M85-HCC1](https://en.wikipedia.org/wiki/M85-HCC1) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/M85-HCC1?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.