 An ultraviolet band light curve for GP Comae Berenices, adapted from Smak (1975). The error bar shown on the leftmost point applies to all points. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 13 05 42.401 |
| Declination | +18° 01′ 03.76″ |
| Apparent magnitude (V) | 15.69 |
| Characteristics | |
| Evolutionary stage | White dwarf |
| Spectral type | DBe |
| Apparent magnitude (g) | 15.929 |
| Variable type | AM CVn |
| Astrometry | |
| Proper motion (μ) | RA: −344.92±0.06 mas/yr Dec.: 34.85±0.06 mas/yr |
| Parallax (π) | 13.7306 ± 0.0452 mas |
| Distance | 237.5 ± 0.8 ly (72.8 ± 0.2 pc) |
| Details | |
| Mass | 0.59±0.09 M☉ |
| Temperature | 14,800±500 K |
| Other designations | |
| Gaia DR2 3938156295111047680, G 61-29, LTT 18284, WD 1303+18, 2MASS J13054243+1801039 | |
| Database references | |
| SIMBAD | data |
GP Comae Berenices, abbreviated to GP Com and also known as G 61-29, is a star system composed of a white dwarf orbited by a planetary mass object, likely the highly eroded core of another white dwarf star. The white dwarf is slowly accreting material from its satellite at a rate of (3.5±0.5)×10 M☉/year and was proven to be a low-activity AM CVn star. The star system is showing signs of a high abundance of ionized nitrogen from the accretion disk around the primary.
In 1971, Brian Warner discovered that the star, then known as G61-29, is a variable star. it was given its variable star designation, GP Comae Berenices, in 1975.
Planetary system
The material emitted from the planetary mass companion is mostly helium, with a molar ratio of nitrogen up to 1.7%, very low neon levels and other elements not detectable at all. Approximately half of the luminosity of the system comes from the accretion disk. The planetary object is suspected to contain a strange quark matter core due to its unusually high density, which must be above 187.5 g/cm to prevent tidal disruption; the theoretical bound for planets composed solely of ordinary matter is on the order of 30 g/cm. The object's orbit is expected to decay within 100 million years due to gravitational wave emission.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (seconds) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 10.5±1.5 MJ | 0.0014 | 2794 | 0 | 59.5±14.5° | ≤ 0.420±0.020 RJ |
References
- Smak, J. (January 1975). "The helium emission-line object G 61-29". Acta Astronomica. 25: 227–233. Bibcode:1975AcA....25..227S. Retrieved 12 December 2021.
- ^ 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.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
- Burbidge, E. M.; Strittmatter, P. A. (1971), "G61 - 29, a Helium Emission-Line Star", The Astrophysical Journal, 170: L39, Bibcode:1971ApJ...170L..39B, doi:10.1086/180836
- ^ Sion, Edward M.; Linnell, Albert P.; Godon, Patrick; Ballouz, Ronald-Louis (2011), "THE HOT COMPONENTS OF AM CVN HELIUM CATACLYSMICS", The Astrophysical Journal, 741 (1): 63, arXiv:1108.1388, Bibcode:2011ApJ...741...63S, doi:10.1088/0004-637X/741/1/63, S2CID 119284962
- "G 61-29". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-12-09.
- ^ Zhang, Xian-Fei; Liu, Jin-Zhong; Jeffery, C. Simon; Hall, Philip D.; Bi, Shao-Lan (2018), "The double helium-white dwarf channel for the formation of AM CVN binaries", Research in Astronomy and Astrophysics, 18 (1): 009, arXiv:1801.03196, Bibcode:2018RAA....18....9Z, doi:10.1088/1674-4527/18/1/9, S2CID 73586281
- Morales-Rueda, L.; Marsh, T. R.; Steeghs, D.; Unda-Sanzana, E.; Wood, J. H.; North, R. C. (2003), "New results on GP Com", Astronomy & Astrophysics, 405: 249–261, arXiv:astro-ph/0304265, Bibcode:2003A&A...405..249M, doi:10.1051/0004-6361:20030552, S2CID 119033361
- ^ Kupfer, T.; Steeghs, D.; Groot, P. J.; Marsh, T. R.; Nelemans, G.; Roelofs, G. H. A. (2016), "UVES and X-Shooter spectroscopy of the emission line AM CVN systems GP Com and V396 Hya", Monthly Notices of the Royal Astronomical Society, 457 (2): 1828, arXiv:1601.02841, Bibcode:2016MNRAS.457.1828K, doi:10.1093/mnras/stw126
- Warner, B. (1971). "Helium emission white dwarfs". IAU Circular. 2374: 1. Bibcode:1971IAUC.2374....1W.
- Warner, B. (1972). "Observations of rapid blue variables - X. G61-29". Monthly Notices of the Royal Astronomical Society. 159 (3): 315–319. Bibcode:1972MNRAS.159..315W. doi:10.1093/mnras/159.3.315. Retrieved 29 January 2025.
- Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (January 1975). "60th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 961: 1–15. Bibcode:1975IBVS..961....1K. Retrieved 29 January 2025.
- Nelemans, G.; Yungelson, L. R.; Sluys, M. V. van der; Tout, Christopher A. (2009), "The chemical composition of donors in AM CVN stars and ultracompact X-ray binaries: Observational tests of their formation", Monthly Notices of the Royal Astronomical Society, 401 (2): 1347–1359, arXiv:0909.3376, doi:10.1111/j.1365-2966.2009.15731.x, S2CID 2716902
- ^ Kuerban, Abudushataer; Geng, Jin-Jun; Huang, Yong-Feng; Zong, Hong-Shi; Gong, Hang (2020), "Close-in Exoplanets as Candidates for Strange Quark Matter Objects", The Astrophysical Journal, 890 (1): 41, arXiv:1908.11191, Bibcode:2020ApJ...890...41K, doi:10.3847/1538-4357/ab698b, S2CID 201671383
