12 Camelopardalis

12 Camelopardalis

12 Camelopardalis (center) in optical light
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Camelopardalis
Right ascension 05h 06m 12.13609s[1]
Declination +59° 01′ 16.8261″[1]
Apparent magnitude (V) 6.08[2]
Characteristics
Evolutionary stage giant
Spectral type K0 IIIe[3]
B−V color index 1.112±0.009[2]
Variable type RS CVn[4]
Astrometry
Radial velocity (Rv)−1.92±0.27[2] km/s
Proper motion (μ) RA: −2.264[1] mas/yr
Dec.: −26.949[1] mas/yr
Parallax (π)4.6513 ± 0.0706 mas[1]
Distance700 ± 10 ly
(215 ± 3 pc)
Absolute magnitude (MV)−0.332[5]
Details
12 Cam A
Mass1.1[6] M☉
Radius23.08+0.75
−1.34[1] R☉
Luminosity212±4[1] L☉
12 Cam B
Mass0.6[6] M☉
Other designations
12 Cam, BM Cam, BD+58°805, HD 32357, HIP 23743, HR 1623, SAO 25003, CCDM 05062+5900, WDS J05061+5858B[7]
Database references
SIMBADdata

12 Camelopardalis is a binary star in the northern circumpolar constellation of Camelopardalis, located 700 light years away from the Sun as determined from parallax measurements.[1] It forms a double star with 11 Camelopardalis, which is only 3 arcminutes away. The system has the variable star designation BM Camelopardalis; 12 Camelopardalis is the Flamsteed designation. It is just visible to the naked eye, appearing as a dim, orange-hued star with an apparent visual magnitude of 6.08.[2] The system is moving closer to the Earth with a heliocentric radial velocity of −2 km/s.[2]

A visual band light curve for BM Camelopardalis, adapted from Zboril and Messina (2009).[8] The main plot shows the long-term variability, and the inset plot shows the variability due to the star's rotation.

Abt et al. (1969) determined this to be a single-lined spectroscopic binary system and computed an orbital solution with a period of 80.17 days and an eccentricity of 0.35.[9] However, what appeared to be an ellipticity effect with a period of 79.93±0.05 d was found, which was inconsistent with the computed orbit, and the lack of modulation of the amplitude did not fit with the large orbital eccentricity. Hall et al. (1995) made additional measurements, finding an orbital period of 80.9 days and an eccentricity that is statistically indistinguishable from zero.[6]

The visible component is an evolved giant star with a stellar classification of K0 IIIe,[3] showing strong emission lines.[9] It is an RS Canum Venaticorum variable and its brightness varies by 0.14 magnitudes with a period of 82.9 days due to starspots.[4] The star is most likely rotating in synchronous manner with its orbital period.[6] The magnetic activity has two overlapping cycles of 14.8 and 8.5 years, with the activity occurring at two latitudes.[8] BM Cam emits X-rays and is the designated X-ray source 1H 0501+592.[10] It has been detected by HEAO 1, the Einstein Observatory, and ROSAT.

  1. ^ a b c d e f g h Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference perkins1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference BohmVitense2000 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Hall1995 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Zboril2009 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Abt1969 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Wood1984 was invoked but never defined (see the help page).