 LkCa 15 protoplanetary disk | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 | |
|---|---|
| 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 mas[3] |
| Distance | 513 ± 2 ly (157.2 ± 0.7 pc) |
| Details | |
| Mass | 0.97 ± 0.03[2] M☉ |
| Radius | 1.2[4] R☉ |
| Luminosity | 1.22[5] L☉ |
| Temperature | 4730[4] K |
| Age | 2[2] Myr |
| Other designations | |
| V1079 Tau,GSC 01278-00193,TYC 1278-193-1,2MASS J04391779+2221034[1] | |
| Database references | |
| SIMBAD | data |
LkCa 15 is aT Tauristar in theTaurus Molecular Cloud. These types of stars are relatively youngpre-main-sequence stars that show irregular variations in brightness.[7] It has a mass that is about 97% of theSun,[2] aneffective temperature of 4370 K,[5] and is slightly cooler than the Sun. Itsapparent magnitude is 11.91,[2] meaning it is not visible to the naked eye.
LkCa 15 is surrounded by aprotoplanetary disk, typical of many T Tauri stars.[7] The disk around the star is about 55 times more massive than Jupiter,[8] 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 aprotoplanetary object orexoplanet orbiting it, known asLkCa 15 b[9][10] This name stems from an older survey.[11] Later, the existence of up to three planets was suspected. The planets' existence was refuted in 2019 as higher resolution imaging became available.[4]
| 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±1MJ | 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]° | — | |||
LkCa 15 b is a candidateprotoplanetary object in orbit around LkCa 15, a star in theTaurus-Auriga Star Forming Region. Its potential discovery was effected by direct imaging techniques using theKeck II telescope in 2011 by Adam Kraus and Michael Ireland.[9] A 2015 study of observations from theMagellan Telescopes and theLarge Binocular Telescope argued that theplanet is forming throughaccretion.[10] It would be the first observedexoplanet seen in the process of active accretion.[12] The planet’s existence was refuted in 2019 as higher resolution imaging became available.[4]
