NGC 638
| NGC 638 | |
|---|---|
 The barred spiral galaxy NGC 638 | |
| Observation data (J2000 epoch) | |
| Constellation | Pisces |
| Right ascension | 01h 39m 37.8s |
| Declination | 07° 14′ 14″ |
| Redshift | +0.010547± 0.000007 |
| Heliocentric radial velocity | 3,162 km/s |
| Distance | 42.24 ± 2.97 Mpc (∼138 million light-year) |
| Apparent magnitude (V) | 13.8 |
| Apparent magnitude (B) | 14.5 |
| Surface brightness | 12.81 mag/am |
| Characteristics | |
| Type | Barred spiral galaxy |
| Size | 47,200 ly (24.48 kpc) |
| Apparent size (V) | 0.8' x 0.5' |
| Other designations | |
| PGC 6145, Mrk 1003, CGCG 412-11 | |
NGC 638 is a barred spiral galaxy located in the constellation of Pisces. Its velocity speed to the cosmic microwave background is 2,864± 21 km/s, which corresponds to a Hubble's law of 42.2 ± 3.0 Mpc (∼138 million light-year).[1] NGC 638 was discovered by American astronomer Lewis A. Swift in 1886.
Only Professor Seligman classifies this galaxy as a barred spiral, and the SDSS survey image proves him right.[original research?]
NGC 638 has a broad Hydrogen line. NGC 638 is a galaxy whose nucleus shines in the ultraviolet domain. It is listed in the Markarian catalogue under the code Mrk 1003 (MK 1003).[2]
To date, two non-redshift measurements give a distance of 55.330 0 ± 1.273 Mpc (∼180 million light-year),[3] which is outside the Hubble distance values. Note that the NASA/IPAC database calculates the diameter of a galaxy using the average value of independent measurements, when available, and that consequently the diameter of NGC 638 could be about 11.1 kpc (∼36,200 light-year) if the Hubble's law were used to calculate it.
NGC 645 Group
[edit]NGC 638 is part of the NGC 645 group which includes at least five galaxies. The other three galaxies in this group are NGC 632, UGC 1137 and UGC 1172.[4]
See also
[edit]Related article
[edit]Other links
[edit]- NGC 638 on spider.seds.org
- NGC 638 on the LEDA database
- NGC 638 on WikiSky
- NGC 638 on the site of Professor C. Seligman
References
[edit]- ^ "By Name | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2024-07-23.
- ^ "NGC 638". astrovalleyfield.ca. Retrieved 2024-07-23.
- ^ "NED Query Results for NGC 638". ned.ipac.caltech.edu. Retrieved 2024-07-23.
- ^ Garcia, A. M. (1993-07-01). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47–90. Bibcode:1993A&AS..100...47G. ISSN 0365-0138.
External links
[edit]
Media related to NGC 638 at Wikimedia Commons
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