Astronomy:CN Andromedae

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Short description: Star in the constellation Andromeda
CN Andromedae
CNAndLightCurve.png
The visual band light curve of CN Andromedae, adapted from a plot presented by Varol Keskin[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  00h 20m 30.54209s[2]
Declination +40° 13′ 33.80342″[2]
Apparent magnitude (V) 9.62 – 10.21 variable [3]
Characteristics
Spectral type F5V[3]
Apparent magnitude (B) 10.24[4]
Apparent magnitude (V) 9.706[4]
Apparent magnitude (G) 9.6637[2]
Apparent magnitude (J) 8.670[5]
Apparent magnitude (H) 8.452[5]
Apparent magnitude (K) 8.427[5]
B−V color index 0.49725[4]
Variable type EB[3]
Astrometry
Radial velocity (Rv)−24.2±1.0[6] km/s
Proper motion (μ) RA: −8.549±0.054 [2] mas/yr
Dec.: −35.291±0.024[2] mas/yr
Parallax (π)4.9670 ± 0.0425[2] mas
Distance657 ± 6 ly
(201 ± 2 pc)
Orbit[6]
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
Details
Primary
Mass1.433±0.030[7] M
Radius1.48±0.03[7] R
Luminosity3.40[7] L
Surface gravity (log g)4.24[6] cgs
Temperature6,450[7] K
Secondary
Mass0.552±0.020[7] M
Radius0.95[7] R
Luminosity0.40[7] L
Surface gravity (log g)4.22[6] cgs
Temperature4,726[7] K
Other designations
2MASS J00203054+4013337, BD+39 59, TYC 2787-1815-1
Database references
SIMBADdata

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 is classified as a Beta Lyrae variable with a period roughly of 0.4628 days.[3]

System

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,[7] and there is a mass flow from the primary star to the secondary at a rate of 1.4 × 10−7 M yr−1.[6] The binary orbit is slowly decaying at rate 1.5*10−7 days/year. The third suspected component of the system is the red dwarf star with mass about 0.11 M, at 38±4 years orbit around binary. [8]

Variability

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.[3] 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 other.[6]

References

  1. Keskin, Varol (March 1989). "Light Changes of the Close Binary System CN Andromedae". Astrophysics and Space Science 153 (2): 191–199. doi:10.1007/BF00636655. Bibcode1989Ap&SS.153..191K. http://articles.adsabs.harvard.edu/pdf/1989Ap%26SS.153..191K. Retrieved 7 October 2021. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. 3.0 3.1 3.2 3.3 3.4 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.
  4. 4.0 4.1 4.2 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics 355: L27–L30, Bibcode2000A&A...355L..27H. 
  5. 5.0 5.1 5.2 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues 2246: II/246. Bibcode2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. 
  6. 6.0 6.1 6.2 6.3 6.4 6.5 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. doi:10.1086/324110. Bibcode2001AJ....122.3436V. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 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. Bibcode2010AcA....60..305S. 
  8. Yildirim, Muhammed (2019). "CN Andromedae: a shallow contact binary with a possible tertiary component". Research in Astronomy and Astrophysics 19 (1): 10-1 - 10-10. doi:10.1088/1674-4527/19/1/10.