20h08m5.75s, ++66° 51′ 2.1″
| |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 20h08m 05.75515s[1] |
| Declination | +66° 51′ 02.0766″[1] |
| Apparent magnitude (V) | 8.971[2] |
| Characteristics | |
| HD 191939 | |
| Evolutionary stage | main sequence |
| Spectral type | G9V[3] |
| Astrometry | |
| Radial velocity (Rv) | −9.23±0.16[1] km/s |
| Proper motion (μ) | RA: 150.194±0.015 mas/yr[1] Dec.: −63.988±0.017 mas/yr[1] |
| Parallax (π) | 18.6967 ± 0.0133 mas[1] |
| Distance | 174.4 ± 0.1 ly (53.49 ± 0.04 pc) |
| Absolute magnitude (MV) | 5.32 |
| Details[3] | |
| HD 191939 | |
| Mass | 0.81±0.04 M☉ |
| Radius | 0.94±0.02 R☉ |
| Luminosity (bolometric) | 0.65±0.02 L☉ |
| Surface gravity (log g) | 4.3±0.1 cgs |
| Temperature | 5348±100 K |
| Metallicity [Fe/H] | −0.15±0.06 dex |
| Rotational velocity (v sin i) | 0.6±0.5[4] km/s |
| Age | 7±3[4] Gyr |
| Other designations | |
Gaia DR2 2248126315275354496, HD 191939, HIP 99175, TOI-1339, TIC 269701147, TYC 4244-964-1, 2MASS J20080574+6651019[5] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 191939 is a single yellow (G-type) main-sequence star, located approximately 174 light-years away in the constellationofDraco, taking its primary name from its Henry Draper Catalogue designation.
HD 191939 is a Sun-like G-type main-sequence star, likely older than the Sun and relatively depleted in metals.
In 2020, an analysis carried out by a team of astronomers led by astronomer Mariona Badenas-Agusti of the TESS project confirmed the existence of three gaseous planets, all smaller than Neptune, in orbit around HD 191939.[4] Another non-transiting gas giant planet designated HD 191939 e was detected in 2021, along with a substellar object on a highly uncertain, 9 to 46 year orbit.[3] In 2022, a sixth planet, with a mass comparable to Uranus, was discovered in the system's habitable zone.[6] The 2021 study also suggested the possible presence of an additional non-transiting planet with a period of 17.7 days,[3] but the 2022 study did not support this.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 10.00±0.70 M🜨 | 0.0804+0.0025 −0.0023 |
8.8803256 | 0.031+0.010 −0.011 |
88.10+0.14 −0.10° |
3.410±0.075 R🜨 |
| c | 8.0±1.0 M🜨 | 0.1752+0.0055 −0.0050 |
28.579743 | 0.034+0.034 −0.013 |
89.10+0.06 −0.08° |
3.195±0.075 R🜨 |
| d | 2.80±0.60 M🜨 | 0.2132+0.0065 −0.0061 |
38.353037 | 0.031+0.018 −0.012 |
89.49+0.05 −0.08° |
2.995±0.070 R🜨 |
| e | ≥112.2±4.0 M🜨 | 0.407±0.012 | 101.12±0.13 | 0.031+0.008 −0.016 |
88.7±0.7[3]° | — |
| g | ≥13.5±2.0 M🜨 | 0.812±0.028 | 284+10 −8 |
0.030+0.025 −0.011 |
— | — |
| f | >2.08 MJ | >3.2 | >2200 | — | — | — |
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