 LkCa 15 protoplanetary disk | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04 39 17.796 |
| Declination | +22° 21′ 03.48″ |
| Apparent magnitude (V) | +11.91 |
| Characteristics | |
| Spectral type | K5V |
| Variable type | T Tauri |
| Astrometry | |
| Proper motion (μ) | RA: 10.572 mas/yr Dec.: -17.527 mas/yr |
| Parallax (π) | 6.3619 ± 0.0264 mas |
| Distance | 513 ± 2 ly (157.2 ± 0.7 pc) |
| Details | |
| Mass | 0.97 ± 0.03 M☉ |
| Radius | 1.2 R☉ |
| Luminosity | 1.22 L☉ |
| Temperature | 4730 K |
| Age | 2 Myr |
| Other designations | |
| V1079 Tau, GSC 01278-00193, TYC 1278-193-1, 2MASS J04391779+2221034 | |
| Database references | |
| SIMBAD | data |
LkCa 15 is a T Tauri star in the Taurus Molecular Cloud. These types of stars are relatively young pre-main-sequence stars that show irregular variations in brightness. It has a mass that is about 97% of the Sun, an effective temperature of 4370 K, and is slightly cooler than the Sun. Its apparent magnitude is 11.91, meaning it is not visible to the naked eye.
Planetary system
LkCa 15 is surrounded by a protoplanetary disk, typical of many T Tauri stars. The disk around the star is about 55 times more massive than Jupiter, and consists of three major belts (components). Small changes in the observed brightness of the disk may be due to a planetary companion; the star was believed to have a protoplanetary object or exoplanet orbiting it, known as LkCa 15 b This name stems from an older survey. Later, the existence of up to three planets was suspected. The planets' existence was refuted in 2019 as higher resolution imaging became available.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| Protoplanetary disk component 1 | 0.12–3 AU | 50° | — | |||
| b (unconfirmed) | 6±1 MJ | 15.7±2.1 | 40000 | — | — | — |
| Protoplanetary disk component 2 | 20–40 AU | 51.5° | — | |||
| Protoplanetary disk component 3 | 55–160 AU | 50° | — | |||
LkCa 15 b is a candidate protoplanetary object in orbit around LkCa 15, a star in the Taurus-Auriga Star Forming Region. Its potential discovery was effected by direct imaging techniques using the Keck II telescope in 2011 by Adam Kraus and Michael Ireland. A 2015 study of observations from the Magellan Telescopes and the Large Binocular Telescope argued that the planet is forming through accretion. It would be the first observed exoplanet seen in the process of active accretion. The planet’s existence was refuted in 2019 as higher resolution imaging became available.
References
- ^ "EM* LkCa 15". SIMBAD. Centre de données astronomiques de Strasbourg.
- ^ "Notes on LKCA 15 b". Extrasolar Planets Encyclopaedia. 1995. Retrieved 26 December 2016.
- ^ 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.
- ^ Currie, Thayne; et al. (2019), "No Clear, Direct Evidence for Multiple Protoplanets Orbiting Lk Ca 15: Lk Ca 15 BCD are Likely Inner Disk Signals", The Astrophysical Journal, 877 (1): L3, arXiv:1905.04322, Bibcode:2019ApJ...877L...3C, doi:10.3847/2041-8213/ab1b42, S2CID 152282903
- ^ Thalmann, C.; Mulders, G. D.; Hodapp, K.; Janson, M.; Grady, C. A.; Min, M.; De Juan Ovelar, M.; Carson, J.; Brandt, T.; Bonnefoy, M.; McElwain, M. W.; Leisenring, J.; Dominik, C.; Henning, T.; Tamura, M. (2014). "The architecture of the Lk Ca 15 transitional disk revealed by high-contrast imaging". Astronomy & Astrophysics. 566: A51. arXiv:1402.1766. Bibcode:2014A&A...566A..51T. doi:10.1051/0004-6361/201322915. S2CID 34485844.
- Alencar, S. H. P.; Bouvier, J.; Donati, J.-F.; Alecian, E.; Folsom, C. P.; Grankin, K.; Hussain, G. A. J.; Hill, C.; Cody, A.-M.; Carmona, A.; Dougados, C.; Gregory, S. G.; Herczeg, G.; Ménard, F.; Moutou, C.; Malo, L.; Takami, M.; collaboration, MaTYSSE (December 2018). "Inner disk structure of the classical T Tauri star LkCa 15". Astronomy and Astrophysics. 620: A195. arXiv:1811.04806. Bibcode:2018A&A...620A.195A. doi:10.1051/0004-6361/201834263.
- ^ "Encyclopedia of Science: T Tauri star". Archived from the original on 27 January 2021. Retrieved 17 January 2017.
- Andrews, Sean M.; Williams, Jonathan P. (2005). "Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective". The Astrophysical Journal. 631 (2): 1134–1160. arXiv:astro-ph/0506187. Bibcode:2005ApJ...631.1134A. doi:10.1086/432712. S2CID 17583379.
- ^ Kraus, Adam L.; Ireland, Michael J. (2012). "LkCa 15: A Young Exoplanet Caught at Formation?". The Astrophysical Journal. 745 (1): 5. arXiv:1110.3808. Bibcode:2012ApJ...745....5K. doi:10.1088/0004-637x/745/1/5. S2CID 73598684.
- ^ Sallum, S.; Follette, K. B.; Eisner, J. A.; Close, L. M.; Hinz, P.; Kratter, K.; Males, J.; Skemer, A.; MacIntosh, B.; Tuthill, P.; Bailey, V.; Defrère, D.; Morzinski, K.; Rodigas, T.; Spalding, E.; Vaz, A.; Weinberger, A. J. (2015). "Accreting protoplanets in the Lk Ca 15 transition disk". Nature. 527 (7578): 342–4. arXiv:1511.07456. Bibcode:2015Natur.527..342S. doi:10.1038/nature15761. PMID 26581290. S2CID 916170.
- Herbig, G. H.; Vrba, F. J.; Rydgren, A. E. (1986). "A spectroscopic survey of the Taurus-Auriga dark clouds for pre-main-sequence stars having CA II H, K emission". The Astronomical Journal. 91: 575. Bibcode:1986AJ.....91..575H. doi:10.1086/114039.
- Irene Klotz (18 November 2015). "Astronomers see planet still growing in its stellar womb". News Daily. Reuters. Archived from the original on 19 November 2015. Retrieved 20 November 2015.
