Epsilon Cassiopeiae
 Segin is the leftmost star in the "W" |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 01h 54m 23.7255s[1] |
| Declination | +63° 40′ 12.365″[1] |
| Apparent magnitude (V) | 3.342 [1] |
| Characteristics | |
| Spectral type | B3III [1] |
| U−B color index | -0.62 [1] |
| B−V color index | -0.15 [1] |
| Variable type | ? |
| Astrometry | |
| Radial velocity (Rv) | −8.1 [1] km/s |
| Proper motion (μ) | RA: 31.98 [1] mas/yr Dec.: −18.16 [1] mas/yr |
| Parallax (π) | 7.38 ± 0.57[1] mas |
| Distance | 440 ± 30 ly (140 ± 10 pc) |
| Absolute magnitude (MV) | −2.31 |
| Details | |
| Mass | 6 [2] M☉ |
| Radius | 7 [2] R☉ |
| Luminosity | 2,500 [2] L☉ |
| Temperature | 15,400 [2] K |
| Metallicity | ? |
| Rotation | 19 km/s. [2] |
| Age | 6.5×107[2] years |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Cassiopeiae (ε Cas, ε Cassiopeiae) is a star system in the constellation Cassiopeia. It has the traditional name Segin.
In Chinese, 閣道 (Gé Dào), meaning Flying Corridor, refers to an asterism consisting of ε Cassiopeiae, ι Cassiopeiae, δ Cassiopeiae, θ Cassiopeiae, ν Cassiopeiae and ο Cassiopeiae.[3] Consequently, ε Cassiopeiae itself is known as 閣道二 (Gé Dào èr, English: the Second Star of Flying Corridor.)[4]
While some published reports incorrectly claim that this star was designated by NASA as Navi, in honor of astronaut Virgil Ivan "Gus" Grissom, one of the three astronauts who died in the Apollo 1 accident,[5] the actual star so designated is Gamma Cassiopeiae in the center of the constellation.[6][7]
Epsilon is a single, blue-white B-type giant with a radius that is 7 times that of the Sun giving it a luminosity that is 2,500 times solar. It has an apparent magnitude of +3.34 and is approximately 440 light years from Earth.
[edit] References
- ^ a b c d e f g h i j "SIMBAD query result: Eps Cas -- Be Star". Centre de Données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HR542. Retrieved 2010-02-21.
- ^ a b c d e f Professor James B. (Jim) Kaler. "SEGIN (Epsilon Cassiopeiae)". University of Illinois. http://stars.astro.illinois.edu/sow/Segin.html. Retrieved 2010-02-21.
- ^ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ Rao, Joe (August 29, 2003). "NightSky Friday: Rotanev, Derf, Navi, and other Backward Star Names". Space.com. http://www.space.com/spacewatch/star_names_030829.html.
[edit] External links
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