Pisces Dwarf
Irregular dwarf galaxy
From Wikipedia, the free encyclopedia
The Pisces Dwarf, also known as Pisces I (Psc I) or LGS3,[1] is an irregular dwarf galaxy and suspected satellite galaxy of the Triangulum Galaxy (M33), located within the Pisces constellation.[2] Discovered by astronomer Valentina Karachentseva in 1976, it is approaching the Milky Way at 287 km/s, evident by its blueshift, and may be a galaxy currently transitioning between a dwarf spheroidal and dwarf irregular galaxy;[3] alternatively, it may be a rare unique version of one of the two types.[2]
| Pisces Dwarf | |
|---|---|
Hubble Space Telescope image of the Pisces Dwarf | |
| Observation data (J2000 epoch) | |
| Constellation | Pisces |
| Right ascension | 01h 03m 55.0s[1] |
| Declination | +21° 53′ 06″[1] |
| Redshift | -287 ± 0 km/s[1] |
| Distance | 2.51 ± 0.08 Mly (769 ± 25 kpc)[2] |
| Apparent magnitude (V) | 14.2[1] |
| Characteristics | |
| Type | dIrr/dSph[1] |
| Apparent size (V) | 2′ × 2′[1] |
| Other designations | |
| Pisces I, Psc I, LGS 3,[1] PGC 3792,[1] LEDA 3792 | |
Structure
The Pisces Dwarf has a very irregular shape, and is composed primarily of moderately aged and young stars, as given by its metallicity of [Fe/H]=−2.10 ± 0.22.[2] Its star formation has declined, with its peak starburst period suspected to be an estimated 8 billion years ago,[4] and a significant lack of new star formation within the past 100 million years.[2][5] It is suspected to be a potential transition galaxy, currently transitioning from a dwarf irregular to a dwarf spheroidal galaxy.[5][6]
