Comet Galaxy
Galaxy in the constellation Sculptor
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The Comet Galaxy[6] (EQ J235144-260358)[2] is a peculiar spiral galaxy located 996.6 megaparsecs (3.3 billion light-years) from Earth in the galaxy cluster Abell 2667 and the constellation Sculptor.[3] This galaxy has slightly more stellar mass than our Milky Way. It was detected on 2 March 2007 with the Hubble Space Telescope.[1]
| Comet Galaxy | |
|---|---|
The Comet Galaxy, as taken by the Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Sculptor |
| Right ascension | 23h 51m 44.03s[1][2] |
| Declination | −26° 03′ 59.6″[1][2] |
| Redshift | 0.2265[1][2] |
| Heliocentric radial velocity | 67,753±89 km/s[3] |
| Galactocentric velocity | 67,778±89 km/s[3] |
| Distance | 3,250 ± 227.7 Mly (996.6 ± 69.8 Mpc)h−1 0.6774 (Comoving)[3] 2.777 Gly (0.8514 Gpc)h−1 0.6774 (Light-travel)[3] |
| Group or cluster | Abell 2667 |
| Apparent magnitude (B) | 18.642[4][2] |
| Characteristics | |
| Type | dIrr[5] |
| Mass | 3.8×108 (stellar)[5] M☉ |
| Size | 170,000 ly × 142,000 ly (52.2 kpc × 43.5 kpc)[3][a] |
| Apparent size (V) | 0.18′ × 0.15′[3] |
| Notable features | Stripped stream of bright blue knots and diffuse wisps of young stars[6] |
| Other designations | |
| 2dFGRS TGS132Z144[3], EQ J235144-260358[2], WISEA J235144.05-260357.9[3], LEDA 3234374,[3] | |
The galaxy is currently traveling through the galactic cluster at 3.6 million km/h (2.17 million mi/h), and as a result is being stripped of much of its matter as a result of the cluster's tidal forces.[5]
Structure
The Comet Galaxy is a unique, peculiar galaxy that features an extended stream of interstellar gas, blue knots (or large clumps of matter), and wisps of bright-blue young stars.[5] It is currently traveling through Abell 2667 at 3.6 million km/h (1,000 km/s[5]), and as a result of the gravitational forces of the cluster, much of the galaxy's matter is being stripped out into a long tail, similar to a comet; as a result, one of the galaxy's arms appears flatter then the surrounding arms, while the tail contains numerous bright starburst regions.[5]
Its isophotal diameter is currently unknown. Based off its apparent size of 10.8 arcseconds for the main galaxy, along with the galaxy's distance from Earth, it approximately corresponds to a diameter of 52.2 kiloparsecs (170,000 light-years), thus making it slightly larger than the Andromeda Galaxy.[3][a]
Fate
The Сomet Galaxy is currently being ripped to pieces, moving through a cluster at speeds of greater than 2 million mph.[5] As the galaxy speeds through, its gas and stars are being stripped away by the tidal forces and charged particles exerted by the cluster.[6] Also contributing to this destructive process is the pressure of the cluster's hot intergalactic gas and plasma, reaching temperatures as high as 100 million degrees.[6] Scientists estimate that the total duration of the transformation process is close to one billion years;[6] the galaxy is seen to be roughly 400 million years into this process.[3][5]
In spite of the galaxy's large mass, the spiral will inevitably lose majority of its gas and dust, resulting in a gas-poor lenticular or elliptical galaxy with an older population of red stars.[3] The finding sheds light on the process by which some gas-rich galaxies might evolve into gas-poor galaxies over billions of years. Observations also reveal one mechanism that may result in intergalactic stars.[2][5]
See also
Notes
- Calculated based on minor and major angular diameters and the quoted comoving distance:
