04h33m 39.72001s[2]
−51° 57′ 22.4354″[2]
12.617[3]
Characteristics
M3.0V[4]
12.617±0.03[3]
12.147±0.05[3]
11.621±0.003[2]
9.099±0.032[3]
8.531±0.073[3]
8.251±0.029[3]
Radial velocity (Rv)
25.90±0.37[2] km/s
Proper motion (μ)
RA: +83.082 mas/yr[2]
Dec.: −269.803 mas/yr[2]
Parallax (π)
73.31 ± 0.02 ly
(22.477 ± 0.007 pc)
Details[5]
0.386±0.008 M☉
0.378±0.011 R☉
Luminosity (bolometric)
0.0194±0.0019 L☉
Surface gravity (log g)
4.872±0.026 cgs
3506±70 K
Metallicity [Fe/H]
−0.20±0.12 dex
Database references
TOI-270, also known as L 231-32, is a red dwarf star 73.3 light-years (22.5 parsecs) 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 (3,233 °C; 5,851 °F). TOI-270 hosts a system of three known exoplanets.
The three planets of TOI-270 were discovered in 2019 by the transit method with TESS.[4] Their masses have since been measured by both Doppler spectroscopy[5] and transit-timing variations.[6] The innermost planet, TOI-270 b, is a rocky super-Earth, while the two outer planets are mini-Neptunes.[5] TOI-270 b & c orbit near a 5:3 resonance, while TOI-270 c & d orbit near a 2:1 resonance.[4]
Observations of the outermost planet, TOI-270 d, by the Hubble Space Telescope suggest a hydrogen-rich atmosphere with signs of water vapor.[7] TOI-270 c & d are good targets for atmospheric detection with the James Webb Space Telescope.[8]
The James Webb Space Telescope detected methane (CH4), carbon dioxide (CO2) and water vapor in the atmosphere of TOI-270 d.[9] The atmosphere of this planet was also found to be metal-rich, with a mean molecular weightof5.47+1.25
−1.14 and an atmospheric metal mass fraction (percentage of the mass of metals in the atmosphere) of 58%+8%
−12%.[9] Possible signatures of sulfur dioxide (SO2) and carbon disulfide (CS2) were also found.[9]
Companion
(in order from star)
b
1.48±0.18 M🜨
0.03197(22)
3.3601538(48)
0.0167(84)
89.39±0.37°
1.206±0.039 R🜨
c
6.20±0.31 M🜨
0.04526(31)
5.6605731(31)
0.0044(6)
89.36±0.24°
2.355±0.064 R🜨
d
4.20±0.16 M🜨
0.07210(50)
11.379573(13)
0.0066(20)
89.73±0.16°
2.133±0.058 R🜨
Other
Other
