Astronomy: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 Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[3] mas |
| Distance | 1,150 ± 10 ly (352 ± 5 pc) |
| Details | |
| Primary | |
| Mass | 0.80[6] M☉ |
| Radius | 0.012[6] R☉ |
| Donor star | |
| Mass | 0.07[6] M☉ |
| Radius | 0.0526[6] R☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
- ↑ "Download Data". AAVSO. https://www.aavso.org/data-download.
- ↑ 2.0 2.1 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, doi:10.1046/j.1365-8711.2000.03440.x, Bibcode: 2000MNRAS.315..140K.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 4.0 4.1 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 5.0 5.1 5.2 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, doi:10.1007/s10509-022-04149-z, 110, Bibcode: 2022Ap&SS.367..110B.
- ↑ 6.0 6.1 6.2 6.3 Boneva, Daniela et al. (August 2021), "Mid-Cycle Observations of CR Boo and Estimation of the System's Parameters", Data 5 (4): 113, doi:10.3390/data5040113.
- ↑ "CR Boo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=CR+Boo.
- ↑ 8.0 8.1 8.2 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, doi:10.1093/pasj/psw063, 64, Bibcode: 2016PASJ...68...64I.
- ↑ 9.0 9.1 9.2 Wood, M. A. et al. (February 1987), "The Exotic Helium Variable PG 1346+082", Astrophysical Journal 313: 757, doi:10.1086/165014, Bibcode: 1987ApJ...313..757W.
- ↑ Green, R. F. et al. (1986). "The Palomar-Green Catalog of Ultraviolet-Excess Stellar Objects". The Astrophysical Journal Supplement Series 61: 305. doi:10.1086/191115. Bibcode: 1986ApJS...61..305G.
Further reading
- 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, doi:10.22323/1.255.0049, 49, Bibcode: 2015gacv.workE..49I.
- 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, doi:10.1086/669542, Bibcode: 2013PASP..125..126H.
- 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, doi:10.1086/133982, Bibcode: 1997PASP..109.1100P.
- 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, doi:10.1086/303971, Bibcode: 1997ApJ...480..383P.
- 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 274: pp. 348–351, doi:10.1007/3-540-17668-3_233, ISBN 978-3-540-17668-8, Bibcode: 1987LNP...274..348W.
- 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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