ST Camelopardalis
{{Short description|Star in the constellation Camelopardalis}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = The visual band light curve of ST Camelopardalis, from AAVSO data
}}
{{Starbox observe
| epoch = J2000.0
| constell = Camelopardalis
}}
{{Starbox character
| type = Carbon star
| appmag_1_passband =
| appmag_1 =
| r-i =
| v-r =
| u-b =
| variable = SRb
}}
{{Starbox astrometry
| radial_v =
| prop_mo_ra = {{val|−2.992|0.136}}
| prop_mo_dec = {{val|−3.237|0.185}}
| parallax = 1.6725
| p_error = 0.0989
}}
{{Starbox detail
| mass =
| gravity =
| age_gyr =
| rotational_velocity =
}}
{{Starbox catalog
| names = ST Camelopardalis, ST Cam, HD 20243, HIP 22552, BD+67°350
}}
{{Starbox reference
| Simbad = ST+Cam
}}
{{Starbox end}}
ST Camelopardalis, abbreviated ST Cam, is a carbon star in the constellation of Camelopardalis. It has a radius of {{Solar radius|244}}. 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.
In 1902, Thomas William Backhouse announced that ST Cam was a low amplitude variable star with a long or irregular period. It was given its variable star designation in 1912.
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.
ST Cam is an AGB star, in the process of expelling its red giant envelope into space. 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.
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 {{nowrap|1.1 × 10−6 }}{{Solar mass}} per year. 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.
References
{{reflist|refs=
{{cite DR2|483958671558728576}}
{{cite journal|author=Stassun K.G.|s2cid=166227927|display-authors=etal|date=October 2019|title=The revised TESS Input Catalog and Candidate Target List|journal=The Astronomical Journal|volume=158|issue=4|page=138|arxiv=1905.10694|bibcode=2019AJ....158..138S|doi=10.3847/1538-3881/ab3467 |doi-access=free }}
{{Cite journal|last1=Howarth|first1=J. J.|last2=Greaves|first2=J.|date=February 2001|title=ST Camelopardalis: A doubly periodic semiregular variable star|journal=Journal of the British Astronomical Association|language=en|volume=111|pages=40–42|bibcode=2001JBAA..111...40H|issn=0007-0297}}
{{cite web|url=http://webviz.u-strasbg.fr/viz-bin/VizieR-S?V*%20ST%20Cam |title=ST Cam database entry |work=Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.) |author1=N. N. Samus |author2=O. V. Durlevich |display-authors=etal |publisher=CDS |accessdate=2018-10-14}}
}}
{{Stars of Camelopardalis}}