CR Boötis

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CR Boötis

A visual band light curve for CR Boötis, plotted from 2019 AAVSO data.[1] The data have been folded with the supercycle period found by Kato et al.[2]
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 13h 48m 55.222s[3]
Declination +07° 57′ 35.72″[3]
Apparent magnitude (V) 13.0 to 17.5[4]
Characteristics
Evolutionary stage Double white dwarf[5]
Variable type Dwarf nova(?)[4]
Astrometry
Proper motion (μ) RA: –34.412[3] mas/yr
Dec.: 13.105[3] mas/yr
Parallax (π)2.8438 ± 0.0367 mas[3]
Distance1,150 ± 10 ly
(352 ± 5 pc)
Details
Primary
Mass0.80[6] M☉
Radius0.012[6] R☉
Donor star
Mass0.07[6] M☉
Radius0.0526[6] R☉
Other designations
CR Boo, SDSS J134855.21+075735.7, PG 1346+082, AAVSO 1344+08[7]
Database references
SIMBADdata

CR Boötis is an interacting binary system in the northern constellation of Boötes, abbreviated CR Boo. It is one of the best-known AM Canum Venaticorum stars.[8] The system varies widely in brightness, ranging in apparent visual magnitude from 13.6 down to 17.5.[2] The distance to this system is approximately 1,150 light years from the Sun, based on parallax measurements.[3]

The variable luminosity of this object was discovered in 1983 by M. A. Wood and associates, with a light curve that is very similar to that of AM Canum Venaticorum.[9] It was found to have an ultraviolet excess by the Palomar-Green survey and assigned the identifier PG 1346+082 in 1986.[10] The system varies in both its photometric and spectroscopic properties, with a photometric quasi-period of 4–5 days. The optical spectrum displays only lines of helium.[9]

Rapid flickering suggests this is a close binary system undergoing mass transfer, while emission by neutral helium indicates there is a thick accretion disk orbiting a compact object. The lack of X-ray emission means this accreting object is a white dwarf, rather than something more massive. The lack of hydrogen in the spectrum demonstrates that the donor star is a helium white dwarf with a lower mass than the primary.[9] The pair have a brief orbital period of 24.522 minutes with a mass ratio of 0.101±0.004.[8] The orbital plane is inclined at an angle of about 30° to the line of sight from the Earth.[5]

This system displays two different states. The first is a lower state of quiescence that displays regular superoutbursts similar to ER Ursae Majoris on a roughly 46 day cycle. The second state is brighter with frequent outbursts.[8] The system becomes bluer during superoutbursts, with a higher temperature.[5]

References[edit]

  1. ^ "Download Data". aavso.org. AAVSO. Retrieved 26 March 2023.
  2. ^ a b Kato, Taichi; et al. (June 2000), "CR Boo: the 'helium ER UMa star' with a 46.3-d supercycle", Monthly Notices of the Royal Astronomical Society, 315 (1): 140–148, Bibcode:2000MNRAS.315..140K, doi:10.1046/j.1365-8711.2000.03440.x, S2CID 121203405.
  3. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  4. ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  5. ^ a b c Boneva, Daniela; et al. (November 2022), "Recent observations of humps and superhumps and an estimation of outburst parameters of the AM CVn star CR Boo", Astrophysics and Space Science, 367 (11): 110, arXiv:2212.07189, Bibcode:2022Ap&SS.367..110B, doi:10.1007/s10509-022-04149-z, S2CID 253631390, 110.
  6. ^ a b c d Boneva, Daniela; et al. (August 2021), "Mid-Cycle Observations of CR Boo and Estimation of the System's Parameters", Data, 5 (4): 113, arXiv:2108.10421, doi:10.3390/data5040113.
  7. ^ "CR Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-03-06.
  8. ^ a b c Isogai, Keisuke; et al. (August 2016), "Superoutburst of CR Bootis: Estimation of mass ratio of a typical AM CVn star by stage A superhumps", Publications of the Astronomical Society of Japan, 68 (4): 64, arXiv:1605.05408, Bibcode:2016PASJ...68...64I, doi:10.1093/pasj/psw063, 64.
  9. ^ a b c Wood, M. A.; et al. (February 1987), "The Exotic Helium Variable PG 1346+082", Astrophysical Journal, 313: 757, Bibcode:1987ApJ...313..757W, doi:10.1086/165014.
  10. ^ Green, R. F.; et al. (1986). "The Palomar-Green Catalog of Ultraviolet-Excess Stellar Objects". The Astrophysical Journal Supplement Series. 61: 305. Bibcode:1986ApJS...61..305G. doi:10.1086/191115.

Further reading[edit]

  • Kato, Taichi; et al. (February 2023), "Genuine standstill in the AM CVn star CR Boo", arXiv:2302.04454 [astro-ph.SR]
  • Isogai, K.; et al. (2015), "Research on AM CVn stars: ASASSN-14ei and CR Boo", Proceedings of The Golden Age of Cataclysmic Variables and Related Objects - III (Golden2015). 7-12 September 2015. Palermo, Italy, p. 049, Bibcode:2015gacv.workE..49I, doi:10.22323/1.255.0049, 49.
  • Honeycutt, R. Kent; et al. (February 2013), "Light Curve of CR Bootis 1990-2012 from the Indiana Long-Term Monitoring Program", Publications of the Astronomical Society of the Pacific, 125 (924): 126, Bibcode:2013PASP..125..126H, doi:10.1086/669542, S2CID 125036114.
  • Kato, Taichi; et al. (June 2001), "The Second Supercycle of the Helium ER UMa Star, CR Boo", Information Bulletin on Variable Stars, 5120: 1, Bibcode:2001IBVS.5120....1K.
  • Patterson, Joseph.; et al. (October 1997), "Superhumps in Cataclysmic Binaries. XII. CR Bootis, a Helium Dwarf Nova", Publications of the Astronomical Society of the Pacific, 109: 1100–1113, Bibcode:1997PASP..109.1100P, doi:10.1086/133982, S2CID 122373469.
  • Provencal, J. L.; et al. (May 1997), "Whole Earth Telescope Observations of the Helium Interacting Binary PG 1346+082 (CR Bootis)", The Astrophysical Journal, 480 (1): 383–394, Bibcode:1997ApJ...480..383P, doi:10.1086/303971, hdl:10183/108834, S2CID 20591761.
  • Wood, M. A.; et al. (1987), Cox, A. N.; Sparks, W. M.; Starrfield, S. G. (eds.), "PG 1346+082: An interacting binary white dwarf system", Stellar Pulsation: Proceedings of a Conference Held as a Memorial to John P. Cox at the Los Alamos National Laboratory Los Alamos, New Mexico, USA, August 11-15,1986, Lecture Notes in Physics, vol. 274, pp. 348–351, Bibcode:1987LNP...274..348W, doi:10.1007/3-540-17668-3_233, ISBN 978-3-540-17668-8.
  • Wood, M. A.; et al. (September 1985), "The Exotic Helium Variable PG 1346+082", Bulletin of the American Astronomical Society, 17: 886, Bibcode:1985BAAS...17..886W.
  • Nather, R. E.; et al. (December 1984), Marsden, B. G. (ed.), "PG 1346+082", IAU Circular, 4021 (2): 2, Bibcode:1984IAUC.4021....2N.
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