ST Camelopardalis
Star in the constellation Camelopardalis
From Wikipedia, the free encyclopedia
ST Camelopardalis, abbreviated ST Cam, is a carbon star in the constellation of Camelopardalis. It has a radius of 244 R☉.[6] Its apparent magnitude ranges from 6.3 to 8.5, so under excellent observing conditions, it could be very faintly visible to the naked eye when it is near maximum brightness.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Camelopardalis |
| Right ascension | 04h 051m 13.348s[2] |
| Declination | +68° 10′ 07.65″[2] |
| Apparent magnitude (V) | 6.3 to 8.5[3] |
| Characteristics | |
| Evolutionary stage | Carbon star |
| Spectral type | C5,4(N5)[3] |
| B−V color index | +2.1[4] |
| Variable type | SRb[3] |
| Astrometry | |
| Proper motion (μ) | RA: −2.992±0.136[2] mas/yr Dec.: −3.237±0.185[2] mas/yr |
| Parallax (π) | 1.6725±0.0989 mas[2] |
| Distance | 2,000 ± 100 ly (600 ± 40 pc) |
| Absolute magnitude (MV) | −1.232[5] |
| Details | |
| Radius | 244[6] R☉ |
| Luminosity | 4,478[2] L☉ |
| Temperature | 3,388[6] K |
| Metallicity [Fe/H] | −0.1[7] dex |
| Other designations | |
| ST Camelopardalis, ST Cam, HD 20243, HIP 22552, BD+67°350 | |
| Database references | |
| SIMBAD | data |
In 1902, Thomas William Backhouse announced that ST Cam was a low amplitude variable star with a long or irregular period.[8] It was given its variable star designation in 1912.[9]
ST Cam is a semiregular variable star. It is doubly periodic, with the two pulsation periods P0 and P1 being equal to 368.6 and 201 days respectively.[10]
ST Cam is an AGB star, in the process of expelling its red giant envelope into space.[11] Line emission from the 115 GHz rotational transition of carbon monoxide was detected in 1987 by Olofson et al. The width of the emission line indicated that ST Cam is surrounded by a circumstellar envelope expanding at 10 km/sec.[12] Bergeat and Chevallier (2005) analyzed later molecular spectroscopy results, and derived an envelope expansion velocity of 9 km/sec, and a mass loss rate of 1.1 × 10−6 M☉ per year.[11] Broadband emission from dust in the envelope was spatially resolved by the IRAS satellite in its 60 micron data. Dust was detected out to a distance of 3.1 arc minutes from the star, or about 1.8 light years assuming a distance to ST Cam of 600 pc.[13]