Exoplanet · mini-Neptune
HIP 9618 b
HIP 9618 b is a mini-Neptune orbiting the star HIP 9618. Its year lasts 20.8 Earth days. It was discovered in 2023 by the Transit method.
| Host star | HIP 9618 |
|---|---|
| Distance | 220.3 light-years (67.5 pc) |
| Orbital period | 20.8 days |
| Orbital radius | 0.145 AU |
| Eccentricity | 0.000 |
| Radius | 3.83 R⊕ · 0.342 R♃ |
| Mass | 8.3 M⊕ · 0.0261 M♃ |
| Density | 0.81 g/cm³ |
| Surface gravity | 0.566 × Earth |
| Equilibrium temperature | 641 K (368 °C) |
| Stellar flux received | 40.3 × Earth |
| Discovery method | Transit |
| Discovery year | 2023 |
| Discovered by | Transiting Exoplanet Survey Satellite (TESS) |
Habitable zone
Inside the inner edge of the habitable zone: it receives 40.3 times the light the Earth does, too hot to keep liquid water on its surface.
Its star in the sky
In the planet's sky its star is a disc 3.5° across: 6.6 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 9.20. Visible from the whole Northern Hemisphere and south to latitude 69° S. North of latitude 69° N it never sets. It stands highest at midnight in October, the best time to observe it.
Light's journey
The light you see tonight set out around the year 1806. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 3.9 million years.
Planets in the same system
- HIP 9618 c 52.6-day orbit · 3.43 R⊕
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.