HD 191939 is 175 light-years from the Sun. The NASA Exoplanet Archive lists 6 planets around this G9 V star; the first was found in 2020 by transit (Transiting Exoplanet Survey Satellite (TESS)).
Fly there in 3DHD 191939 b goes round its star every 8.88 days, 10 times as often as Mercury goes round the Sun.
| Spectral type | G9 V |
| Surface temperature | 5,348 K |
| Mass | 0.81 solar masses |
| Radius | 0.94 solar radii |
| Luminosity | 0.65 times the Sun |
| Apparent magnitude | 8.97 |
| Age | about 8.7 billion years |
| Distance from the Sun | 174.8 light-years (53.6 parsecs) |
| Position (J2000) | RA 302.0256°, Dec 66.8503° |
| Constellation | Draco |
| Planet | Year | Orbit | Radius | Mass | Found |
|---|---|---|---|---|---|
| HD 191939 b | 8.88 days | 0.0804 AU | 3.41 R⊕ | 10 M⊕ | Transit, 2020 |
| HD 191939 c | 28.6 days | 0.175 AU | 3.195 R⊕ | 8 M⊕ | Transit, 2020 |
| HD 191939 d | 38.4 days | 0.213 AU | 2.995 R⊕ | 2.8 M⊕ | Transit, 2020 |
| HD 191939 e | 101.1 days | 0.407 AU | 13 R⊕ estimated | 112.2 M⊕ minimum | Radial Velocity, 2022 |
| HD 191939 g | 284.0 days | 0.812 AU | 3.74 R⊕ estimated | 13.5 M⊕ minimum | Radial Velocity, 2022 |
| HD 191939 f | 7.9 years | 3.710 AU | 13.2 R⊕ estimated | 915.35 M⊕ minimum | Radial Velocity, 2022 |
Values are the NASA Exoplanet Archive’s composite parameters. A radius marked estimated comes from a mass–radius relation; a mass marked minimum is M sin i. Planet sizes and colours in the 3D view are renderings: none of these worlds has been photographed as more than a point of light.