| Type 2 | H I region |
|---|---|
| Epoch | J2000.0[1][2] |
| Ra | [2] |
| Dec | [2] |
| Dist ly | ×106 [2] |
| Dist pc | 11.8×106 [2] |
| Constellation | Leo |
| Radius ly | 325×103 [3] |
| Radius pc | 100×103 [4] |
The Leo Ring is an immense intergalactic cloud of hydrogen and helium gas some 650 kly in diameter, in orbit of two galaxies, in the center of the Leo Group of galaxies, within the constellation of Leo.
Observation history
Radio astronomers discovered the cloud in 1983. Astronomers had theorized that the ring was primordial gas in the process of forming a galaxy. The GALEX satellite detected ultraviolet emissions that astronomers at Johns Hopkins University and the Carnegie Institution for Science interpret to indicate star creation in newly forming dwarf galaxies in a 19 February 2009 Nature paper.[5] In 2010, it was suggested that the gas was not primordial, but instead the result of a galactic collision between the two galaxies with which the ring is closely associated.[3]
In 2021, analysis of several dense areas revealed several H II regions, powered by massive stars, a few which are O-type stars.[6]
Formation history
It has been suggested that 1.2 billion years ago, NGC 3384 collided with M96, at the heart of the Leo Group, expelling a galaxy's worth of gas into intergalactic space. This gas gathered into a vast set of clouds, the Leo Ring.[3][4]
The ring is now 650 kly wide. The ring is composed of a collection of H I regions. A bridge of gas connects the ring to M96.[3][4]
References
- ^ "NAME Leo Ring"
- ^ "Leo Ring". NASA/IPAC Intergalactic Database. Archived 2022-04-23 at the Wayback Machine. Retrieved 2015-11-08.
- ^ Léo Michel-Dansa & Pierre-Alain Duc (2010). "The mysterious Leo giant gas ring explained by a billion year old collision between two galaxies". Canada France Hawaii Telescope. Archived 2013-10-10 at the Wayback Machine. Retrieved 2015-11-08.
- ^ Michel-Dansac, Leo; Duc, Pierre-Alain; Bournaud, Frederic; Cuillandre, Jean-Charles; Emsellem, Eric; Oosterloo, Tom; Morganti, Raffaella; Serra, Paolo; Ibata, Rodrigo (2010). "A collisional origin for the Leo ring". The Astrophysical Journal Letters. 717 (2): L143–L148. arXiv:1005.4208. Bibcode:2010ApJ...717L.143M. doi:10.1088/2041-8205/717/2/L143. S2CID 54012759
- ^ "New stars from old gas surprise astronomers". PhysOrg.com. 18 February 2009. Archived 26 September 2011 at the Wayback Machine. Retrieved 18 February 2009.
- ^ Corbelli, Edvige; Mannucci, Filippo; Thilker, David; Cresci, Giovanni; Venturi, Giacomo (2021-07-01). "Gaseous nebulae and massive stars in the giant H I ring in Leo". Astronomy and Astrophysics. 651: A77. arXiv:2104.07133. doi:10.1051/0004-6361/202140398. ISSN 0004-6361