TOI-270

Source: Wikipedia, the free encyclopedia.
TOI-270
Observation data
J2000
Constellation Pictor[1]
Right ascension 04h 33m 39.72001s[2]
Declination −51° 57′ 22.4354″[2]
Apparent magnitude (V) 12.617[3]
Characteristics
Evolutionary stage Main sequence
Spectral type M3.0V[4]
Apparent magnitude (V) 12.617±0.03[3]
Apparent magnitude (R) 12.147±0.05[3]
Apparent magnitude (G) 11.621±0.003[2]
Apparent magnitude (J) 9.099±0.032[3]
Apparent magnitude (H) 8.531±0.073[3]
Apparent magnitude (K) 8.251±0.029[3]
Distance
73.31 ± 0.02 ly
(22.477 ± 0.007 pc)
Details
dex
TIC 259377017, 2MASS J04333970-5157222[3]
Database references
Exoplanet Archive
data

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.

Planetary system

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 weight of 5.47+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]

The TOI-270 planetary system[5][6]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
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🜨
Comparison of the TOI-270 planetary system to Jupiter's moon system[10]
Artist's impression of the three known planets in the TOI-270 system and their size comparison with Earth

References

  1. ^ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
  2. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  3. ^ a b c d e f g "L 231-32". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 18 October 2023.
  4. ^
    S2CID 256707535
    .
  5. ^
    doi:10.1093/mnras/stab2143
    .
  6. ^
    doi:10.1093/mnras/stab3483
    .
  7. doi:10.3847/1538-3881/aca90b
    .
  8. doi:10.1093/mnras/staa1198
    .
  9. ^
    arXiv:2403.03325
  10. ^ Reddy, Francis (29 July 2019). "NASA's TESS Mission Scores 'Hat Trick' With 3 New Worlds". NASA. Retrieved 18 October 2023.
Retrieved from "https://en.wikipedia.org/w/index.php?title=TOI-270&oldid=1281976794"