LkCa 15

Summary

LkCa 15
LkCa 15 disk protoplanetare Scheibe cropped.jpg
LkCa 15 protoplanetary Disk
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 04h 39m 17.796s[1]
Declination +22° 21′ 03.48″[1]
Apparent magnitude (V) +11.91[2]
Characteristics
Spectral type K5V[2]
Variable type T Tauri[1]
Astrometry
Proper motion (μ) RA: 10.572[3] mas/yr
Dec.: -17.527[3] mas/yr
Parallax (π)6.3619 ± 0.0264[3] mas
Distance513 ± 2 ly
(157.2 ± 0.7 pc)
Details
Mass0.97 ± 0.03[2] M
Radius1.2[4] R
Luminosity1.22[5] L
Temperature4730[4] K
Age2[2] Myr
Other designations
V1079 Tau, GSC 01278-00193, TYC 1278-193-1, 2MASS J04391779+2221034[1]
Database references
SIMBADdata

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.[6] It has a mass that is about 97% of the Sun,[2] an effective temperature of 4370 K,[5] and is slightly cooler than the Sun. Its apparent magnitude is 11.91,[2] 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.[6] The disk around the star is about 55 times more massive than Jupiter,[7] and consists of three major belts (components).[4] 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[8][9] This name stems from an older survey.[10] Later, the existence of up to three planets was suspected. The planets existence was refuted in 2019 as higher resolution imaging became available.[4]

The HD 95086 planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
Protoplanetary disk component 1 0.12–3[4] AU 50[4]°
b (unconfirmed) 6±1 MJ 15.7±2.1 40000
Protoplanetary disk component 2 20–40[4] AU 51.5[4]°
Protoplanetary disk component 3 55–160[4] AU 50[4]°

References

  1. ^ a b c d "EM* LkCa 15". SIMBAD. Centre de données astronomiques de Strasbourg.
  2. ^ a b c d e f "Notes on LKCA 15 b". Retrieved 26 December 2016.
  3. ^ a b c 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. Gaia EDR3 record for this source at VizieR.
  4. ^ a b c d e f g h i j No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals, 2019, arXiv:1905.04322
  5. ^ a b 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.
  6. ^ a b "Encyclopedia of Science: T Tauri star". Retrieved 17 January 2017.
  7. ^ 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.
  8. ^ 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.
  9. ^ 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.
  10. ^ 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.