Beta Andromedae
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| Observation data Epoch J2000 |
|
|---|---|
| Constellation (pronunciation) |
Andromeda |
| Right ascension | 01h 09m 43.9s |
| Declination | +35° 37′ 14″ |
| Apparent magnitude (V) | 2.07 |
| Characteristics | |
| Spectral type | M0 IIa |
| U-B color index | 1.96 |
| B-V color index | 1.58 |
| Variable type | Semiregular |
| Astrometry | |
| Radial velocity (Rv) | 3 km/s |
| Proper motion (μ) | RA: 177 mas/yr Dec.: -109 mas/yr |
| Parallax (π) | 16.36 ± 0.76 mas |
| Distance | 199 ± 9 ly (61 ± 3 pc) |
| Absolute magnitude (MV) | -1.87 |
| Details | |
| Mass | 3–4 M☉ |
| Radius | 130 R☉ |
| Luminosity | 1,900 L☉ |
| Temperature | 3,350 K |
| Metallicity | ? |
| Rotation | ? |
| Age | ? years |
| Visual binary orbit | |
| Companion | β And B |
| Semimajor axis (a) | 27" |
| Inclination (i) | 202° |
| Visual binary orbit | |
| Companion | β And C |
| Semimajor axis (a) | 94.8" |
| Inclination (i) | 273° |
| Visual binary orbit | |
| Companion | β And D |
| Semimajor axis (a) | 80.4" |
| Inclination (i) | 144° |
| Visual binary orbit | |
| Companion | β And E |
| Semimajor axis (a) | 24.6" |
| Eccentricity (e) | 126 |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Andromedae (β And / β Andromedae) is a star in the constellation Andromeda. It has the traditional name Mirach (also spelled Merach, Mirac, Mirak, Mirakh, Merak) from the Arabic المراق al-maraqq "the Loins"; the names Mirar, Mirath, Mirax, El Mizar, Al Mizar may be misreadings.
Mirach is a red giant of spectral class M0, approximately 200 light years away, with a mean apparent magnitude of 2.07. It is classified as a semiregular variable star and its brightness varies from magnitude +2.01 to +2.10.
Close by (in terms of celestial coordinates) is the galaxy known as Mirach's Ghost.
[edit] Location
The star's location is shown in the following chart of the Andromeda constellation:
[edit] Reference
- http://server6.sky-map.org/imageView?image_id=381
- http://www.astro.uiuc.edu/~kaler/sow/andromeda-p.html
- http://www.alcyone.de/cgi-bin/search.pl?object=HR0337
- Image MIRACH
[edit] Components
| NAME | Right ascension | Declination | Apparent magnitude (V) | Database references |
|---|---|---|---|---|
| β Andromedae B | 01h 09m 42.2s | +35° 36' 54 | 14.4 | Simbad |
| β Andromedae C | 01h 09m 35.334s | +35° 36' 24.4 | 12.9 | Simbad |
| β Andromedae D | 01h 09m 47s | +35° 36' 14 | 12.1 | Simbad |
| β Andromedae E | Simbad |
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