BD Camelopardalis

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Template:Short description

BD Camelopardalis
File:BDCamLightCurve.png
A light curve for BD Camelopardalis from Hipparcos data, adapted from Adelman (1998)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Camelopardalis
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 5.11[3]
Characteristics
Evolutionary stage AGB[4]
Spectral type S3.5/2[5] (M4III)[6]
U−B Template:Engvar 1.82[7]
B−V Template:Engvar 1.63[7]
R−I Template:Engvar 1.39
Variable type Lb[8]
Astrometry
Radial velocity (Rv)−22.28[9] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[2]
Dec.: +20.052 mas/yr[2]
Parallax (π)4.2671±0.2581 mas[2]
DistanceScript error: No such module "val". ly
(Script error: No such module "val". pc)[10]
Absolute magnitude (MV)−0.90
Orbit[11]
PrimaryBD Cam A
CompanionBD Cam B
Period (P)596.2 days
Eccentricity (e)0.088
Inclination (i)105.6°
Longitude of the node (Ω)162.1°
Periastron epoch (T)2442794.5
Argument of periastron (ω)
(secondary)
334.3°
Details
Red giant primary
Mass2.68[12] Template:Solar mass
RadiusScript error: No such module "val".[13] Template:Solar radius
Luminosity2,000[14] Template:Solar luminosity
Surface gravity (log g)1.5[12] cgs
TemperatureScript error: No such module "val".[14] K
MetallicityScript error: No such module "val".[12]
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
BD Cam, SAO 12874, BD+62°597, HD 22649, HIP 17296, FK5 129, HR 1105[15]
Database references
SIMBADdata

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BD Camelopardalis is an S star and symbiotic star in the constellation Camelopardalis. It is a 5th magnitude star, and is visible to the naked eye under good observing conditions. It was recognized as a spectroscopic binary star in 1922, and its orbital solution published in 1984;[16] it has a 596-day orbital period. A spectroscopic composition analysis was done of the red giant primary star in 1986.[17]

Description

Although the star's spectrum shows the spectral features of zirconium oxide which define spectral class S, BD Cam shows no technetium lines in its spectrum. It is believed to be an "extrinsic" S star, one whose s-process element excesses originate in a binary companion star.

In 1928, Joel Stebbins and Charles Morse Huffer announced that the star, then called HR 1105, is a variable star, based on observations made at Washburn Observatory.[18] It was given its variable star designation, BD Camelopardalis, in 1977.[19] The system displays only minimal variations in the visible, but the presence of the companion and its interactions with the stellar wind of the visible red giant makes for easily observed time-variable spectral features in the ultraviolet and in the near infrared spectral line of helium.

At times BD Cam is the brightest S star in the visible sky, because other bright S stars are Mira variables or other types of variable star with large changes in apparent brightness. Its own brightness variability in the visible part of the spectrum is modest.

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References

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  14. a b Script error: No such module "Citation/CS1". BD Cam's database entry at VizieR.
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Further reading

Template:Stars of Camelopardalis