The spectral type of U Camelopardalis in therevised MK system is C-N5, which indicates a classical carbon star spectrum approximately corresponding to late K or early M.[10] The C2 index is 5.5 which is typical of a C-N star.[11] It is also given an alternative spectral type ofMS4, indicating a star similar to an M4 class but with somewhat enhanced ZrO bands.[3] The spectral type may vary between C3,9 and C6,4e.[4]
In 1891,Williamina Fleming announced that the star (then known as DM +62°.596) is a variable star, based on 13 photographs taken in 1890 and 1891.[13] It was listed with itsvariable star designation, U Camelopardalis, inAnnie Jump Cannon's 1907 workSecond Catalog of Variable Stars.[14] U Camelopardalis is acarbon star. These types of stars have greater levels ofcarbon in their atmospheres thanoxygen, which means they form carbon compounds that make the star appear strikingly red. U Camelopardalis is nearly 4 magnitudes fainter at blue wavelengths than in the centre of the visual range. In theinfraredK band it has an apparent magnitude of 0.37.[15] Its brightness varies without a dominant period and it is classified assemi-regular, although a period of 400 days has been published.[15] In theV photometric band the brightness varies by around half a magnitude,[16] but the amplitude is nearly two magnitudes at blue wavelengths.[4] The maximum visual magnitude has been given as 7.2.[7]
The shell of gas surrounding U Camelopardalis was imaged by theHubble Space Telescope in 2012, showing a nearly perfect sphere of gas surrounding the star.[17]
U Cameloparadlis has a 10th magnitude companion 308" away. It is a B8main sequence star, hotter but less luminous than U Cam itself. They are not thought to be physically associated.[7]
^abcNicolet, B. (1978). "Catalogue of homogeneous data in the UBV photoelectric photometric system".Astronomy and Astrophysics.34:1–49.Bibcode:1978A&AS...34....1N.
^abBarnbaum, Cecilia; Stone, Remington P. S.; Keenan, Philip C. (1996). "A Moderate-Resolution Spectral Atlas of Carbon Stars: R, J, N, CH, and Barium Stars".Astrophysical Journal Supplement.105: 419.Bibcode:1996ApJS..105..419B.doi:10.1086/192323.
^abcSamus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)".VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S.1.Bibcode:2009yCat....102025S.
