CS Camelopardalis

CS Camelopardalis (CS Cam; HD 21291) is a binary star in reflection nebula VdB 14, in the constellation Camelopardalis. It is a 4th magnitude star, and is visible to the naked eye under good observing conditions.

CS Camelopardalis

Location of CS Camelopardalis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Camelopardalis
A
Right ascension	03h 29m 04.13196s[1]
Declination	+59° 56′ 25.1970″[1]
Apparent magnitude (V)	4.22[2] (4.19 - 4.23[3])
B
Right ascension	03h 29m 04.22561s[4]
Declination	+59° 56′ 25.9860″[4]
Apparent magnitude (V)	7.75[5]
Characteristics
A
Spectral type	B9 Ia[6]
U−B color index	−0.23[2]
B−V color index	+0.41[2]
Variable type	α Cyg[7]
B
Spectral type	B2III[8]
Astrometry
A
Radial velocity (Rv)	−5.10[9] km/s
Proper motion (μ)	RA: −2.751[1] mas/yr Dec.: −1.066[1] mas/yr
Parallax (π)	1.0527±0.1311 mas[1]
Distance	approx. 3,100 ly (approx. 900 pc)
Absolute magnitude (MV)	−7.10[10]
B
Proper motion (μ)	RA: −1.702[4] mas/yr Dec.: −0.646[4] mas/yr
Parallax (π)	0.9642 ± 0.0601 mas[4]
Distance	3,400 ± 200 ly (1,040 ± 60 pc)
Details
Mass	19[11] M☉
Radius	85.7[11] R☉
Luminosity	75,900[12] L☉
Surface gravity (log g)	1.65[6] cgs
Temperature	10,800[6] K
Rotational velocity (v sin i)	30[13] km/s
Age	16.5[14] Myr
Other designations
ADS 2544, BD+59°660, CCDM 03291+5956, GC 4113, HD 21291, HIP 16228, HR 1035, SAO 24054, WDS J03291+5956
Database references
SIMBAD	data
Data sources:
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.)

It forms a group of stars known as the Camelopardalis R1 association, part of the Cam OB1 association. The near-identical supergiant CE Camelopardalis is located half a degree to the south.

As a binary star, CS Cam is designated as Struve 385 (STF 385, Σ385).^[15]

A light curve for CS Camelopardalis, adapted from Morel et al. (2004)^[16]

The primary component, CS Camelopardalis A, is a blue-white B-type supergiant with a mean apparent magnitude of 4.21^m. The star was found to be a variable star when the Hipparcos data was analyzed. It was given its variable star designation in 1999.^[17] It is classified as an Alpha Cygni type variable star and its brightness varies from magnitude 4.19^m to 4.23^m. Its companion, CS Camelopardalis B, is a magnitude 8.7^m blue giant star located 2.4 arcseconds from the primary.^[18]