 A visual band light curve for CR Boötis, plotted from 2019 AAVSO data. The data have been folded with the supercycle period found by Kato et al. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13 48 55.222 |
| Declination | +07° 57′ 35.72″ |
| Apparent magnitude (V) | 13.0 to 17.5 |
| Characteristics | |
| Evolutionary stage | Double white dwarf |
| Variable type | Dwarf nova(?) |
| Astrometry | |
| Proper motion (μ) | RA: –34.412 mas/yr Dec.: 13.105 mas/yr |
| Parallax (π) | 2.8438 ± 0.0367 mas |
| Distance | 1,150 ± 10 ly (352 ± 5 pc) |
| Details | |
| Primary | |
| Mass | 0.80 M☉ |
| Radius | 0.012 R☉ |
| Donor star | |
| Mass | 0.07 M☉ |
| Radius | 0.0526 R☉ |
| Other designations | |
| CR Boo, SDSS J134855.21+075735.7, PG 1346+082, AAVSO 1344+08 | |
| 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. The system varies widely in brightness, ranging in apparent visual magnitude from 13.6 down to 17.5. The distance to this system is approximately 1,150 light years from the Sun, based on parallax measurements.
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. It was found to have an ultraviolet excess by the Palomar-Green survey and assigned the identifier PG 1346+082 in 1986. 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. It was given its variable star designation, CR Boötis, in 1987, in literature up until that time it was called PG 1346+082.
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. The pair have a brief orbital period of 24.522 minutes with a mass ratio of 0.101±0.004. The orbital plane is inclined at an angle of about 30° to the line of sight from the Earth.
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. The system becomes bluer during superoutbursts, with a higher temperature.
References
- "Download Data". aavso.org. AAVSO. Retrieved 26 March 2023.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- "CR Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2023-03-06.
- ^ 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.
- ^ 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.
- 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.
- Kholopov, P. N.; Samus, N. N.; Kazarovets, E. V.; Kireeva, N. N. (August 1987). "The 68th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 3058: 1–30. Bibcode:1987IBVS.3058....1K. Retrieved 5 December 2024.
Further reading
- Kato, Taichi; et al. (February 2023), "Genuine standstill in the AM CVn star CR Boo", arXiv:2302.04454
- 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.
