CN Andromedae

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
CN Andromedae
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension  00h 20m 30.54209s[1]
Declination +40° 13′ 33.80342″[1]
Apparent magnitude (V) 9.62 – 10.21 variable [2]
Spectral type F5V[2]
Apparent magnitude (B) 10.24[3]
Apparent magnitude (V) 9.706[3]
Apparent magnitude (G) 9.6637[1]
Apparent magnitude (J) 8.670[4]
Apparent magnitude (H) 8.452[4]
Apparent magnitude (K) 8.427[4]
B−V color index 0.49725[3]
Variable type EB[2]
Radial velocity (Rv)−24.2±1.0[5] km/s
Proper motion (μ) RA: −8.549±0.054 [1] mas/yr
Dec.: −35.291±0.024[1] mas/yr
Parallax (π)4.9670 ± 0.0425[1] mas
Distance657 ± 6 ly
(201 ± 2 pc)
Period (P)0.4627952±0.000035 days
Semi-major axis (a)3.066±0.035
Inclination (i)68.51±0.17°
Periastron epoch (T)HJD 2445231.51710±0.00059
Mass1.433±0.030[6] M
Radius1.48±0.03[6] R
Luminosity3.40[6] L
Surface gravity (log g)4.24[5] cgs
Temperature6,450[6] K
Mass0.552±0.020[6] M
Radius0.95[6] R
Luminosity0.40[6] L
Surface gravity (log g)4.22[5] cgs
Temperature4,726[6] K
Other designations
2MASS J00203054+4013337, BD+39 59, TYC 2787-1815-1
Database references

CN Andromedae (CN And) is an eclipsing binary star in the constellation Andromeda. Its maximum apparent visual magnitude is 9.62 and drops down to a minimum of 10.2 during the main eclipse. It's classified as a Beta Lyrae variable with a period roughly of 0.4628 days.[2]


The two stars in this system orbit very close to each other; their spectrum cannot be separated and as a whole they have a spectrum of an F5V star. They are in marginal contact,[6] and there is a mass flow from the primary star to the secondary at a rate of 1.4 × 10−7 M yr−1.[5]


The light curve of CN Andromedae shows a primary eclipse, with its brightness dropping down to 10.21 magnitude, and a secondary one down to a magnitude of 9.9.[2] This phenomenon repeats with a cycle of approximately 11.1 hours, with period decreasing in time due to the mass transfer from one star to the another.[5]


  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e CN And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2018-10-17.
  3. ^ a b c Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
  4. ^ a b c Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; et al. (June 2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues (2246): II/246. Bibcode:2003yCat.2246....0C.
  5. ^ a b c d e f Van Hamme, W.; Samec, R. G.; Gothard, N. W.; Wilson, R. E.; Faulkner, D. R.; Branly, R. M. (2001). "CN Andromedae: A Broken-Contact Binary?". The Astronomical Journal. 122 (6): 3436–3446. Bibcode:2001AJ....122.3436V. doi:10.1086/324110.
  6. ^ a b c d e f g h i Siwak, M.; Zola, S.; Koziel-Wierzbowska, D. (2010). "A Study of Contact Binaries with Large Temperature Differences between Components". Acta Astronomica. 60 (4): 305–336. Bibcode:2010AcA....60..305S.