K2-19
Orangish-hued star in the constellation Virgo
From Wikipedia, the free encyclopedia
K2-19 is an early K-type[4] or late G-type main sequence star[5] that is magnetically active, and has a light curve that exhibits variations in brightness of ~1%.[5] It is located approximately 976 light-years away in the constellation Virgo. Three confirmed transiting exoplanets are known to orbit this star.
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Virgo[1] |
| Right ascension | 11h 39m 50.4803s[2] |
| Declination | +00° 36′ 12.875″[2] |
| Apparent magnitude (V) | 13.002±0.009[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | K0 V[4] or G9V[5] |
| Apparent magnitude (J) | 11.596±0.024[6] |
| Apparent magnitude (H) | 11.208±0.022[6] |
| Apparent magnitude (K) | 11.161±0.026[6] |
| Apparent magnitude (B) | 13.798±0.020[3] |
| Variable type | Planetary transit variable[7] |
| Astrometry | |
| Radial velocity (Rv) | −7.2296±0.0080[8] km/s |
| Proper motion (μ) | RA: −18.673(22)[2] mas/yr Dec.: 4.571(15)[2] mas/yr |
| Parallax (π) | 3.3410±0.0196 mas[2] |
| Distance | 976 ± 6 ly (299 ± 2 pc) |
| Details[9] | |
| Mass | 0.892(34) M☉ |
| Radius | 0.824(24) R☉ |
| Surface gravity (log g) | 4.556(24) cgs |
| Temperature | 5350(110) K |
| Metallicity [Fe/H] | 0.03(2) dex |
| Rotation | 18.36(51) d |
| Rotational velocity (v sin i) | 3.00(50)[4] km/s |
| Age | 1.70(25) Gyr |
| Other designations | |
| UCAC4 454-050261, EPIC 201505350, 2MASS J11395048+0036129, Gaia DR3 3798833775141351552[10] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Planetary system
Discovery
The two outer planets were reported as planet candidates during analysis of data from Campaign 1 of the Kepler space telescope's K2 extended mission.[11] Both planets were confirmed by David J. Armstrong and collaborators, who used ground-based telescopes to detect additional transits and measure hour-long transit-timing variations for K2-19b.[7] They were independently validated along with 20 other planets by Benjamin T. Montet and team.[12]
K2-19d was first reported as a planet candidate during a search for candidates from the first year of the K2 Mission[13] and was later validated by Sinukoff et al.[5]
A fourth possible planet orbiting further out was reported in 2025.[9]
Characteristics
K2-19 has a planetary system with three known planets, of which the two larger ones, K2-19b and K2-19c, are either close to the 3:2 mean motion resonance or inside it.[14][15] All three planets orbit closer to their star than the planet Mercury does to the Sun.[4][16]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| d | <6.2 M🜨 | 0.03478(43) | 2.50827+0.00027 −0.00014 |
<0.44 | 89.7(1.6) | 1.044(64) R🜨 |
| b | 30.8(1.3) M🜨 | 0.07487(90) | 7.922806(90) | 0.040(24) | 89.70(26) | 6.59(22) R🜨 |
| c | 11.12(44) M🜨 | 0.0982(12) | 11.89770(46) | 0.067(17) | 89.37(15) | 3.88(14) R🜨 |
| e (candidate) | <2.0 M🜨 | 0.1387(17) | 19.9724(54) | <0.15 | 89.20+0.17 −0.43 |
1.22(15) R🜨 |