The HD 191939 system contains 6 exoplanets. It is located 174.85 light years away from the solar system.
| Mass | 0.81 solar masses |
| Radius | 0.94 solar radiae |
| Temperature | 5348 kelvin |
| Stellar Metallicity | -0.15 decimal exponent |
| Age | 8.7 billion years |
At more than 10 Earth masses, HD 191939 b is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune.
| Mass | 10.000 Earth masses |
| Density | 1.400 grams per cubic centimeter |
| Radius | 3.410 Earth radiae |
| Semi-major Axis | 0.0804 AU |
| Eccentricity | 0.031 |
| Orbital Period | 8.880 days |
| Discovery Method | Transit |
| Discovery Facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery Telescope | 0.1 m TESS Telescope |
| Discovery Instrument | TESS CCD Array |
| Discovery Date | 2020-09 |
| Reference | Badenas-Agusti et al. 2020 |
At more than 10 Earth masses, HD 191939 c is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune.
| Mass | 8.000 Earth masses |
| Density | 1.350 grams per cubic centimeter |
| Radius | 3.195 Earth radiae |
| Semi-major Axis | 0.1752 AU |
| Eccentricity | 0.034 |
| Orbital Period | 28.580 days |
| Discovery Method | Transit |
| Discovery Facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery Telescope | 0.1 m TESS Telescope |
| Discovery Instrument | TESS CCD Array |
| Discovery Date | 2020-09 |
| Reference | Badenas-Agusti et al. 2020 |
With a mass below 5 Earth masses, a density of 0.57, and a semi-major axis of 0.2132 astronomical units, HD 191939 d could, potentially, be an ocean world - a planet with no dry land.
| Mass | 2.800 Earth masses |
| Density | 0.570 grams per cubic centimeter |
| Radius | 2.995 Earth radiae |
| Semi-major Axis | 0.2132 AU |
| Eccentricity | 0.031 |
| Orbital Period | 38.353 days |
| Discovery Method | Transit |
| Discovery Facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery Telescope | 0.1 m TESS Telescope |
| Discovery Instrument | TESS CCD Array |
| Discovery Date | 2020-09 |
| Reference | Badenas-Agusti et al. 2020 |
At more than 50 Earth masses, HD 191939 e is a gas giant, a planet whose mass is mostly made up of hydrogen and helium, like Jupiter and Saturn.
| Mass | 112.200 Earth masses |
| Density | 0.281 grams per cubic centimeter |
| Radius | 13.000 Earth radiae |
| Semi-major Axis | 0.407 AU |
| Eccentricity | 0.031 |
| Orbital Period | 101.120 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | W. M. Keck Observatory |
| Discovery Telescope | 10 m Keck I Telescope |
| Discovery Instrument | HIRES Spectrometer |
| Discovery Date | 2022-02 |
| Reference | Lubin et al. 2022 |
At more than 50 Earth masses, HD 191939 f is a gas giant, a planet whose mass is mostly made up of hydrogen and helium, like Jupiter and Saturn.
| Mass | 660.000 Earth masses |
| Density | 1.510 grams per cubic centimeter |
| Radius | 13.400 Earth radiae |
| Semi-major Axis | 3.2 AU |
| Eccentricity | 0 |
| Orbital Period | 2200.000 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | W. M. Keck Observatory |
| Discovery Telescope | 10 m Keck I Telescope |
| Discovery Instrument | HIRES Spectrometer |
| Discovery Date | 2022-02 |
| Reference | Lubin et al. 2022 |
At more than 10 Earth masses, HD 191939 g is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune.
| Mass | 13.500 Earth masses |
| Density | 1.420 grams per cubic centimeter |
| Radius | 3.740 Earth radiae |
| Semi-major Axis | 0.812 AU |
| Eccentricity | 0.03 |
| Orbital Period | 284.000 days |
| Discovery Method | Transit |
| Discovery Facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery Telescope | 0.1 m TESS Telescope |
| Discovery Instrument | TESS CCD Array |
| Discovery Date | 2022-11 |
| Reference | Orell-Miquel et al. 2022 |