TOI-700

TOI-700 planetary system
Credit: NASA's Goddard Space Flight Center
Observation data
Epoch J2000      Equinox J2000
Constellation Dorado[1][2]
Right ascension 06h 28m 22.97s[3]
Declination −65° 34′ 43.01″[3]
Apparent magnitude (V) 13.10±0.01[4]
Characteristics
Evolutionary stage Main sequence
Spectral type M2V[4]
Astrometry
Radial velocity (Rv)-4.4±0.1[4] km/s
Proper motion (μ) RA: -102.750±0.051[5] mas/yr
Dec.: 161.805±0.060[5] mas/yr
Parallax (π)32.0980 ± 0.0211 mas[5]
Distance101.61 ± 0.07 ly
(31.15 ± 0.02 pc)
Details
Mass0.416 ± 0.010[4] M☉
Radius0.420 ± 0.031[4] R☉
Luminosity0.0233 ± 0.0011[4] L☉
Surface gravity (log g)4.81 ± 0.06[4] cgs
Temperature3480 ± 135[4] K
Metallicity [Fe/H]-0.07 ± 0.11[4] dex
Rotation54.0 ± 0.8[4] d
Age>1.5[4] Gyr
Other designations
TIC 150428135, UCAC3 49-21611, 2MASS J06282325-6534456, WISE J062823.05-653443.7, APASS 31812705, Gaia DR2 5284517766615492736
Database references
SIMBADdata

TOI-700 is a red dwarf 101.4 light-years away from Earth[3][5] located in the Dorado constellation that hosts TOI-700 d, the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS).[1][2][6]

Nomenclature and history

The acronym "TOI" refers to stars and exoplanets studied by TESS, and is short for: "Transiting Exoplanet Survey Satellite Object of Interest".

Stellar characteristics

TOI-700 is a red dwarf of spectral class M (much redder, cooler, and dimmer than the sun) that is 40% the mass, 40% the radius and 55% of the temperature of the Sun.[6] The star is bright with low levels of stellar activity. Over the 11 sectors observed with TESS, the star does not show a single white-light flare. The low rotation rate is also an indicator of low stellar activity.[4]

Planetary system

Four exoplanets have been detected by TESS to be orbiting the host star TOI-700. All four exoplanets may be tidally locked to TOI-700.[6][7]

Three papers describe the validation of the planetary system, the follow-up observations of TOI-700 d with the Spitzer Space Telescope and the characterization of TOI-700 d.[4][8][9]

The composition of planets b and d is more likely rocky and the composition of planet c is more likely similar to that of Neptune.[4]

The two inner planets might have grown faster and accreted significant gaseous envelopes, but the outer planet formed more slowly and accreted less gas. The innermost planet may later have lost its envelope due to photoevaporation. Another scenario that could explain the arrangement of densities in this system is long-term planetary migration. Planet c might have migrated inwards, but this scenario is more plausible if future studies show that planet c is significantly more massive than planet b or d.[4]

Potentially habitable planets

TOI-700 d

Artwork of exoplanet TOI-700 d

TOI-700 d lies in the habitable zone. It receives 35 times more EUV photons than Earth, but also 50 times less than TRAPPIST-1 e. The host star has low stellar activity. The atmosphere of a planet with an Earth-like pressure would survive for longer than 1 Gyr.[4] Simulations of the planet have shown that TOI-700 d is a robust candidate for a habitable world. The simulated spectral feature depths from transmission spectra and the peak flux and variations from synthesized phase curves do not exceed 10 ppm. This will likely prohibit JWST from characterizing the atmosphere of TOI-700 d.[9]

TOI-700 e

TOI-700 e concept art

In November 2021, a fourth possible planet, Earth-sized and receiving approximately 30% more flux from TOI-700 than Earth does from the Sun, was found at the inner edge of the habitable zone of TOI-700.[10] In January 2023 the existence of this planet, designated 700 e, was confirmed.[7]

Discovered in 2023, TOI-700 e is terrestrial exoplanet that NASA claims to be an "earth-like" planet, with 95 percent of the Earth’s radius. Discovered by NASA's TESS (Transitioning Exoplanet Survey Satellite), TOI-700 e has mass of about 0.818 Earths and takes 27.8 days to orbit once around its star.[11] The planet is in a habitable zone distance from the M-type star TOI-700 it orbits, leading NASA scientists to believe that there is potential for liquid water on its surface. Ten percent smaller than its neighboring planet TOI-700 d, both are at a distance from their sun to be considered habitable, however, TESS requires an additional year to acquire more data about the exoplanets.[12] Being one in only about a dozen habitable zone planets known, further research and data collection of the TOI-700 solar system is important for understanding Earth-like planets.[13]

Near orbital resonance

The system is near (but not in) orbital resonance: from planets b to d, period ratios are approximately 5:8, 4:7, 3:4.

The TOI-700 planetary system[14][note 1]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 1.07+0.80
−0.43[4] M🜨		 0.0677±0.0011 9.977219+0.000041
−0.000038		 0.075+0.093
−0.054		 89.60+0.27
−0.29°		 0.914+0.053
−0.049 R🜨
c 7.48+5.89
−3.30[4] M🜨		 0.0929±0.0015 16.051137±0.000020 0.068+0.070
−0.049		 88.903+0.071
−0.087°		 2.60+0.14
−0.13 R🜨
e 0.818 M🜨 0.1340±0.0022 27.80978+0.00046
−0.00040		 0.059+0.057
−0.042		 89.60+0.21
−0.16°		 0.953+0.089
−0.075 R🜨
d 1.72+1.29
−0.63[4] M🜨		 0.1633±0.0027 37.42396+0.00039
−0.00035		 0.042+0.045
−0.030		 89.80+0.12
−0.10°		 1.073+0.059
−0.054 R🜨

See also

Notes

  1. ↑ The masses of these planets have not been measured; the values in this table are estimated from a mass-radius relationship.

References

  1. 1 2 Andreolo, Claire; Cofield, Calla; Kazmierczak, Jeanette (6 January 2020). "NASA Planet Hunter Finds Earth-Size Habitable-Zone World". NASA. Retrieved 6 January 2020.
  2. 1 2 Garner, Rob (6 January 2020). "NASA Planet Hunter Finds Earth-Size Habitable-Zone World". NASA. Retrieved 6 January 2020.
  3. 1 2 3 "ExoFOP TIC 150428135". exofop.ipac.caltech.edu. Retrieved 7 January 2020.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Gilbert, Emily A.; Barclay, Thomas; Schlieder, Joshua E.; Quintana, Elisa V.; Hord, Benjamin J.; Kostov, Veselin B.; Lopez, Eric D.; Rowe, Jason F.; Hoffman, Kelsey; Walkowicz, Lucianne M.; Silverstein, Michele L. (3 January 2020). "The First Habitable Zone Earth-sized Planet from TESS. I: Validation of the TOI-700 System". The Astronomical Journal. 160 (3): 116. arXiv:2001.00952. Bibcode:2020AJ....160..116G. doi:10.3847/1538-3881/aba4b2. S2CID 209862554.
  5. 1 2 3 4 Gaia Collaboration (1 August 2018). "Gaia Data Release 2 - Summary of the contents and survey properties". Astronomy & Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. S2CID 49211658.
  6. 1 2 3 Wall, Mike (6 January 2020). "NASA's TESS Planet Hunter Finds Its 1st Earth-Size World in 'Habitable Zone'". Space.com. Retrieved 6 January 2020.
  7. 1 2 "Second Earth-sized World Found in System's Habitable Zone". exoplanets.nasa.gov. NASA. 10 January 2023. Retrieved 10 January 2023.
  8. ↑ Rodriguez, Joseph E.; Vanderburg, Andrew; Zieba, Sebastian; Kreidberg, Laura; Morley, Caroline V.; Kane, Stephen R.; Spencer, Alton; Quinn, Samuel N.; Eastman, Jason D.; Cloutier, Ryan; Huang, Chelsea X. (3 January 2020). "The First Habitable Zone Earth-Sized Planet From TESS II: Spitzer Confirms TOI-700 d". The Astronomical Journal. 160 (3): 117. arXiv:2001.00954. Bibcode:2020AJ....160..117R. doi:10.3847/1538-3881/aba4b3. S2CID 209862553.
  9. 1 2 Suissa, Gabrielle; Wolf, Eric T.; Kopparapu, Ravi kumar; Villanueva, Geronimo L.; Fauchez, Thomas; Mandell, Avi M.; Arney, Giada; Gilbert, Emily A.; Schlieder, Joshua E.; Barclay, Thomas; Quintana, Elisa V. (3 January 2020). "The First Habitable Zone Earth-sized Planet from TESS. III: Climate States and Characterization Prospects for TOI-700 d". The Astronomical Journal. 160 (3): 118. arXiv:2001.00955. Bibcode:2020AJ....160..118S. doi:10.3847/1538-3881/aba4b4. S2CID 209862275.
  10. ↑ "ExoFOP TIC 150428135". exofop.ipac.caltech.edu. Retrieved 26 November 2021.
  11. ↑ Kazmierczak, Jeanette (9 January 2023). "NASA's TESS Discovers Planetary System's Second Earth-Size World". NASA. Retrieved 20 March 2023.
  12. ↑ Kazmierczak, Jeanette (9 January 2023). "NASA's TESS Discovers Planetary System's Second Earth-Size World". NASA. Retrieved 16 April 2023.
  13. ↑ Haghighipour, Nader (2015), "Kepler 186f: First Earth-Sized Planet in Habitable Zone", in Gargaud, Muriel; Irvine, William M.; Amils, Ricardo; Cleaves, Henderson James (eds.), Encyclopedia of Astrobiology, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 1325–1326, Bibcode:2015enas.book.1530H, doi:10.1007/978-3-662-44185-5_5294, ISBN 978-3-662-44184-8, retrieved 16 April 2023
  14. ↑ Gilbert, Emily A.; Vanderburg, Andrew; et al. (January 2023). "A Second Earth-Sized Planet in the Habitable Zone of the M Dwarf, TOI-700". The Astrophysical Journal Letters. 944 (2): L35. arXiv:2301.03617. Bibcode:2023ApJ...944L..35G. doi:10.3847/2041-8213/acb599. S2CID 255570018.
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