Astronomy:AR Andromedae

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Short description: Star in the constellation Andromeda
AR Andromedae
ARAndLightCurve.png
A visual band light curve for AR Andromedae, from AAVSO data, showing five outbursts.[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  01h 45m 03.27155s[2]
Declination +37° 58′ 33.2379″[2]
Apparent magnitude (V) 11.0 – 17.6 variable[3]
Characteristics
Spectral type pec(UG)[3]
Apparent magnitude (B) 12.8
Apparent magnitude (V) 11.00[4]
Apparent magnitude (G) 16.3185[2]
Apparent magnitude (J) 14.589[5]
Apparent magnitude (H) 13.996[5]
Apparent magnitude (K) 13.730[5]
Variable type UGSS[3]
Astrometry
Proper motion (μ) RA: 5.431±0.046[2] mas/yr
Dec.: −7.249±0.059[2] mas/yr
Parallax (π)2.4070 ± 0.0666[2] mas
Distance1,360 ± 40 ly
(420 ± 10 pc)
Orbit[6]
Period (P)0.16302±0.00032 days
Periastron epoch (T)HJD 2450005.6924±0.0021
Semi-amplitude (K1)
(primary)		91±7 km/s
Other designations
2MASS J01450327+3756334, CRTS J014503.3+375633[7]
Database references
SIMBADdata

AR Andromedae (AR And) is a dwarf nova of the SS Cygni type in the constellation Andromeda. Its typical apparent visual magnitude is 17.6, but increases up to 11.0 magnitude during outbursts. The outbursts occur approximately every 23 days.[3]

System

Dwarf novae systems are made up by a classical star with a white dwarf companion. By measuring the Doppler shift of spectral lines, it was found to have an orbital period of 3.91 hours.[6] The accretion disk around white dwarf seems to be axisymmetric and devoid of structure.[8]

Variability

AR Andromedae was first listed as a variable star by Frank Elmore Ross in 1929, based on observations in 1907 (when the star was too faint to detect) and 1927 (when the star had flared to magnitude 12).[9] It was initially classified as a Mira variable star.[10] In 1934 it was given the variable star designation AR Andromedae.[11]

The light emitted by dwarf novae like AR Andromedae comes entirely from the accretion disc and the white dwarf; the luminosity increase during outbursts is typically induced by a variation in the accretion rate of the white dwarf. The outbursts are unusually frequent, with 19 outbursts detected by 2016.[12]

Spectrum

The spectral type of AR Andromedae is classified as peculiar of the U Geminorum type,[3] since the spectrum is not a typical stellar blackbody. It also shows strong emission lines of the first two Balmer series lines as well as HeI ones. In addition, an unusually strong FeII line with other possible weak lines of the same origin were also reported.[6]

References

  1. ↑ "Download Data". AAVSO. https://www.aavso.org/data-download. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 AR 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 2018-10-24.
  4. ↑ Database entry, Catalogue of Stellar Photometry in Johnson's 11-color system (2002 Ed.), J. R. Ducati, CDS ID [1] Accessed on line 2018-10-24.
  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. Bibcode: 2003yCat.2246....0C. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. 
  6. ↑ 6.0 6.1 6.2 Taylor, C. J.; Thorstensen, J. R. (October 1996). "Orbital Periods of the Dwarf Novae AR And, AM Cas, and PY Per". Publications of the Astronomical Society of the Pacific 108: 894. doi:10.1086/133810. Bibcode: 1996PASP..108..894T. 
  7. ↑ "AR And". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=AR+And. 
  8. ↑ Ruiz-Carmona, R.; Groot, P. J.; Steeghs, D. (2019), "A systematic study of spiral density waves in the accretion discs of cataclysmic variables", Monthly Notices of the Royal Astronomical Society 491 (2): 2217–2253, doi:10.1093/mnras/stz2992 
  9. ↑ Ross, F. E. (August 1929). "New variable stars (eight list) - New proper-motion stars. (seventh list)". Astronomical Journal 39: 140–142. doi:10.1086/104923. Bibcode: 1929AJ.....39..140R. https://articles.adsabs.harvard.edu/pdf/1929AJ.....39..140R. Retrieved 12 March 2023. 
  10. ↑ Morgenroth, O. (December 1933). "62 neue Veränderlilche". Astronomische Nachrichten 250 (5): 75. doi:10.1002/asna.19332500503. Bibcode: 1933AN....250...75M. https://onlinelibrary.wiley.com/doi/pdf/10.1002/asna.19332500503. Retrieved 12 March 2023. 
  11. ↑ Guthnick, P.; Prager, R. (April 1934). "Benennung von veränderlichen Sternen". Astronomische Nachrichten 251 (17): 257. doi:10.1002/asna.19342511702. Bibcode: 1934AN....251..257G. https://onlinelibrary.wiley.com/doi/pdf/10.1002/asna.19342511702. Retrieved 12 March 2023. 
  12. ↑ Statistical properties of dwarf novae-type cataclysmic variables: the outburst catalogue supplementary data



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