NASA (Exoplanet Catalog artwork)TOI-270 d
A nearby sub-Neptune whose JWST spectrum is rich in methane and water
Overview
TOI-270 is a red dwarf star 73.3 light-years away in the constellation Pictor. It has about 39% the mass and 38% the radius of the Sun, and a temperature of about 3,506 K. TOI-270 hosts a system of three known exoplanets.
Source: Wikipedia
NASA: TOI-270 d is a Neptune-like exoplanet that orbits a M-type star. Its mass is 4.2 Earths, it takes 11.4 days to complete one orbit of its star, and is 0.0721 AU from its star. Its discovery was announced in 2019.
Why it matters
- Part of a three-planet system only 73 light-years away, dubbed a 'Rosetta stone' for small planets.
- JWST detected water, methane and carbon dioxide in 2024, hinting at a hot, water-rich envelope.
- The planets' sizes straddle the gap between rocky super-Earths and gassy sub-Neptunes.
NASA puts it this way: “TOI-270 d is a Neptune-like exoplanet that orbits an M-type star. Its mass is 4.78 Earths, it takes 11.4 days to complete one orbit of its star, and is 0.0721 AU from its star. Its discovery was announced in 2019.”
Discovery & system
- Discovered
- 2019 · Transit · Transiting Exoplanet Survey Satellite (TESS)
- Discovery paper
- Günther et al. 2019
- Host star
- TOI-270 · M3 V · 3,506 K · 0.39 M☉
- System
- 3 known planets
- Siblings
- TOI-270 b, TOI-270 c
The system
| World | Period | Distance | Radius | Mass | Temp. |
|---|---|---|---|---|---|
| TOI-270 b | 3.36 d | 0.032 AU | 1.28 R⊕ | 1.48 M⊕ | 600 K |
| TOI-270 c | 5.66 d | 0.045 AU | 2.33 R⊕ | 6.2 M⊕ | 489 K |
| TOI-270 d | 11.4 d | 0.072 AU | 2 R⊕ | 4.2 M⊕ | 383 K |
By the numbers
- Radius
- 2 R⊕12,742 km
- Mass
- 4.2 M⊕25.08 ×10²⁴ kg
- Orbital period
- 11.4 d0.03 yr
- Distance from star
- 0.072 AU10.79 million km
- Eccentricity
- 0.007nearly circular
- Equilibrium temp.
- 383 K110 °C
- Starlight received
- 9 × Earth
- Distance from Earth
- 73.3 ly22.5 pc
- Density
- 2.9 g/cm³0.53 × Earth
Sources
Image: NASA (Exoplanet Catalog artwork) · NASA media: generally free of copyright · image page
Text: Wikipedia (CC BY-SA 4.0). Taglines and highlights are editorial.