9 Ceti
sine wave. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 22m 51.788s[2] |
| Declination | −12° 12′ 33.97″[2] |
| Apparent magnitude (V) | 6.38 - 6.43[3] |
| Characteristics | |
| Spectral type | G3 V[4] |
| U−B color index | +0.09[5] |
| B−V color index | +0.659±0.004[6] |
| Variable type | BY Dra[3] |
| Absolute magnitude (MV) | 4.79[6] |
| Details | |
Myr | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
9 Ceti is a
This is a
G-type main sequence star with a stellar classification of G3 V,[4] which means it is generating energy through the fusion of hydrogen into helium at its core. The mass and radius of the star are similar to the Sun,[14] although the abundance of elements other than hydrogen and helium is about 50% greater.[7] It is much younger than the Sun, being an estimated 850 million years of age.[7] The effective temperature of the stellar atmosphere is around 5,807 K,[9] giving it the yellow-hued glow of a G-type star.[15]
In 1980, this was found to be a
star spot activity in the photosphere,[10] and hence it is classified as a BY Draconis variable.[3] There is considerable variation in the strength of the surface activity—to the point where it has appeared inactive during some observation runs. The strength of the surface magnetic field was measured to be 450 G.[10] The spectrum of this star includes lines of titanium oxide and calcium hydride, which, for a star of this class, is further evidence of star spot activity. Star spots cover an estimated 3% of the surface.[16]
9 Ceti has been examined for evidence of a planetary companion or a
stellar kinematic group.[18]
There is a magnitude 12.57
arc seconds from 9 Ceti along a position angle of 294° (as of 1999).[19] The pair are not physically associated as they have different proper motions[17] and the fainter star has a much smaller parallax.[20]
References
- ^ "Hipparcos Tools Interactive Data Access", Hipparcos, ESA, retrieved 8 December 2021.
- ^ S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ Bibcode:1985IBVS.2681....1K.
- ^ S2CID 16080025.
- Bibcode:1986EgUBV........0M.
- ^ S2CID 119257644.
- ^ S2CID 21698677, A7.
- ^ .
- ^ S2CID 18728713.
- ^ .
- ^ "9 Cet", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2015-12-10.
- doi:10.1086/125956.
- S2CID 12332945.
- S2CID 18775378.
- Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the originalon March 18, 2012, retrieved 2012-01-16
- doi:10.1086/184323.
- ^ S2CID 119237891.
- .
- doi:10.1086/323920, retrieved 2015-07-22
- S2CID 244398875. Gaia DR3 record for this source at VizieR.