Altarf
Stern Altarf (β Cancri) |
|||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
AladinLite | |||||||||||||||||||||
Observation dates equinox : J2000.0 , epoch : J2000.0 |
|||||||||||||||||||||
Constellation | cancer | ||||||||||||||||||||
Right ascension | 08 h 16 m 30.92 s | ||||||||||||||||||||
declination | + 09 ° 11 ′ 8 ″ | ||||||||||||||||||||
Apparent brightness | 3.52 mag | ||||||||||||||||||||
Typing | |||||||||||||||||||||
Known exoplanets | 1 | ||||||||||||||||||||
B − V color index | (1.48) | ||||||||||||||||||||
U − B color index | (1.75) | ||||||||||||||||||||
R − I index | (0.80) | ||||||||||||||||||||
Spectral class | K4 III | ||||||||||||||||||||
Variable star type | Yes | ||||||||||||||||||||
Astrometry | |||||||||||||||||||||
Radial velocity | (22.94 ± 0.19) km / s | ||||||||||||||||||||
parallax | (11.04 ± 0.66) mas | ||||||||||||||||||||
distance | (295 ± 20) ly (90) pc |
||||||||||||||||||||
Proper movement | |||||||||||||||||||||
Rec. Share: | (-48.99 ± 0.97) mas / a | ||||||||||||||||||||
Dec. portion: | (-50.84 ± 0.68) mas / a | ||||||||||||||||||||
Physical Properties | |||||||||||||||||||||
Dimensions | (1.7 ± 0.1) M ☉ | ||||||||||||||||||||
radius | (47.2 ± 1.3) R ☉ | ||||||||||||||||||||
Luminosity |
(900) L ☉ |
||||||||||||||||||||
Effective temperature | (4000) K. | ||||||||||||||||||||
Metallicity [Fe / H] | (-0.29 ± 0.06) | ||||||||||||||||||||
Age | (1.85 ± 0.34) bill. A | ||||||||||||||||||||
Other names and catalog entries |
|||||||||||||||||||||
|
Altarf is the proper name of the star Beta Cancri (β Cancri). It is a giant star of the spectral class K4 (K4IIIBa0.5) and has an apparent magnitude of +3.5 mag. Its distance from the earth is about 300 light years , it is the brightest star in the constellation Cancer .
The star has a very massive companion, beta Cancri b , which weighs around 8 M J and was discovered in 2014 using the radial velocity method. The exoplanet orbits the star at a distance of 1.7 AU with an orbital period of about 600 days.
Web links
Individual evidence
- ↑ a b c d e f g h bet Cnc. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed September 14, 2018 .
- ↑ a b c d e f beta Cnc b. In: Extrasolar Planets Encyclopaedia . Retrieved September 14, 2018 .
- ^ NSV 3973. In: VSX. AAVSO, accessed September 14, 2018 .
- ↑ a b bet Cnc b. In: NASA Exoplanet Archive . Retrieved September 14, 2018 .