GJ 1132 b

GJ 1132 b
Size comparison of GJ 1132 b with Earth
Discovery[1]
Discovered byMEarth-South Array Team
Discovery site Chile
Discovery dateMay 10, 2015 (announced)[2] November 12, 2015 (confirmed)[3]
Transit
Orbital characteristics[4][5]
0.01570±0.00013 AU
Eccentricity0.0118+0.047
−0.0099
1.62892911+0.00000029
−0.00000030 d
Inclination86.58°±0.63°[6]
Semi-amplitude2.98±0.30 m/s
StarGJ 1132
Physical characteristics[7]
1.130±0.056 R🜨
Mass1.66±0.23 M🜨
Mean density
6.3±1.3 g/cm3
12.9±2.2 m/s2
13.6±1.0 km/s
Albedo0.19+0.12
−0.15[4]
Temperature583.8+11
−8.5 K (310.6 °C; 591.2 °F, equilibrium)[4]
709±31 K (436 °C; 817 °F, day side)[4]
Atmosphere
Composition by volumeNone or extremely thin[4]

GJ 1132 b (also known as Gliese 1132 b) is an exoplanet orbiting GJ 1132, a red dwarf star 41 light-years (13 parsecs) from Earth,[1] in the constellation Vela. The planet is considered uninhabitable but was thought to be cool enough to possess an atmosphere.[2] GJ 1132 b was discovered by the MEarth-South array in Chile.[8]

It had been called "one of the most important planets ever discovered beyond the Solar System": Due to its relative proximity to Earth, telescopes should have been able to determine the composition of its atmosphere, the speed of its winds and the color of its sunsets,[9][10][11] if an atmosphere was present. This is due in part to the small diameter of its parent star (20% that of the Sun), which increases the effect on the star's light of its transits. The planet's diameter is approximately 20% larger than that of the Earth[1] and its mass is estimated at 1.6 times that of Earth,[2] implying that it has an Earth-like rocky composition.[12] GJ 1132 b orbits its star every 1.6 days at a distance of 1.4 million miles (2.24 million kilometres).[8]

The planet receives 19 times more stellar radiation than Earth.[1] The equilibrium temperature is estimated at 529 K (256 °C; 493 °F) for an Earth-like albedo, or 409 K (136 °C; 277 °F) for a Venus-like albedo. The planet is likely to be hotter than Venus, as higher temperatures likely prevail at the surface if the planet has an atmosphere.[12]

Atmosphere

GJ 1132b has been subject to multiple claims about the detection of an atmosphere. In April 2017, a hydrogen-dominated atmosphere was claimed to have been detected around GJ 1132 b.[13][6] However, subsequent, more precise work ruled out the claim.[14] Instead, in 2021 detection of a hazy hydrogen atmosphere without helium but with the admixture methane and hydrogen cyanide (implying substantial underlying free nitrogen in the mix, at around 8.9% of the atmosphere) was claimed.[15] However, two subsequent studies found no evidence for molecular absorption in the HST WFC3 Spectrum of GJ 1132 b. Instead, the spectrum was found to be flat,[16][17] which is more consistent with our current understanding of photoevaporation.[citation needed]

A secondary eclipse observed by the James Webb Space Telescope and published in 2024 revealed a substellar temperature of 709±31 K (436 °C; 817 °F). This is only slightly below the maximum possible dayside temperature of 746+11
−14 K (473 °C; 883 °F), assuming a zero albedo planet with no heat redistribution. The thermal emission spectra rules out pure-carbon dioxide atmospheres above 0.006 bar and pure-water vapor atmospheres above 0.16 bar.[4] Therefore, GJ 1132b likely has little to no atmosphere, consistent with the idea of the "Cosmic Shoreline"[4] and similar to other hot rocky M-Dwarf planets including LHS 3844 b (Kua'kua),[18] GJ 1252 b, TRAPPIST-1b[19] and c,[20] GJ 367b (Tahay), and GJ 486b (Su).[21]

See also

References

  1. ^ a b c d Berta-Thompson, Zachory K.; et al. (2015). "A rocky planet transiting a nearby low-mass star". Nature. 527 (7577): 204–207. arXiv:1511.03550. Bibcode:2015Natur.527..204B. doi:10.1038/nature15762. PMID 26560298. S2CID 4385619.
  2. ^ a b c Chu, Jennifer (November 11, 2015). "New exoplanet in our neighborhood". MIT News. Retrieved 2015-11-12.
  3. ^ NASA Exoplanet Archive New ticker slide 1
  4. ^ a b c d e f g Xue, Qiao; Bean, Jacob L.; Zhang, Michael; Mahajan, Alexandra S.; Ih, Jegug; Eastman, Jason D.; Lunine, Jonathan I.; Mansfield, Megan Weiner; Coy, Brandon P.; Kempton, Eliza M.-R.; Koll, Daniel D.; Kite, Edwin S. (2024). "JWST Thermal Emission of the Terrestrial Exoplanet GJ 1132b". arXiv:2408.13340.
  5. ^ Kokori, A.; et al. (14 February 2023). "ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations". The Astrophysical Journal Supplement Series. 265 (1) 4. arXiv:2209.09673. Bibcode:2023ApJS..265....4K. doi:10.3847/1538-4365/ac9da4. Vizier catalog entry
  6. ^ a b Southworth, John; et al. (2017). "Detection of the Atmosphere of the 1.6 M🜨 Exoplanet GJ 1132 b". The Astronomical Journal. 153 (4): 191. arXiv:1612.02425. Bibcode:2017AJ....153..191S. doi:10.3847/1538-3881/aa6477. S2CID 119049452.
  7. ^ Bonfils, X.; et al. (October 2018), "Radial velocity follow-up of GJ1132 with HARPS. A precise mass for planet 'b' and the discovery of a second planet", Astronomy & Astrophysics, 618: 12, arXiv:1806.03870, Bibcode:2018A&A...618A.142B, doi:10.1051/0004-6361/201731884, S2CID 119394477, A142.
  8. ^ a b "Astronomers Eager to Get a Whiff of Newfound Venus-like Planet". Harvard–Smithsonian Center for Astrophysics. November 11, 2015. Retrieved 2015-11-12.
  9. ^ Sample, Ian (11 November 2015). "Earth-like world could be 'most important planet found outside solar system'". The Guardian. Retrieved 2015-11-11.
  10. ^ Burgess, Matt. "Exoplanet GJ 1132b: the 'most important' ever found". Wired UK. Retrieved 2015-11-12.
  11. ^ "Getting Up Close and Personal with an Earth-Sized Exoplanet". The Kavli Foundation. November 11, 2015. Archived from the original on 2017-06-07. Retrieved 2015-11-13.
  12. ^ a b Eva Botkin-Kowacki (2015-11-11). "Spotted: A rocky Earth-sized planet close by". The Christian Science Monitor.
  13. ^ "Atmosphere around super-Earth detected". Phys.Org. April 6, 2017. Retrieved April 6, 2017.
  14. ^ Diamond-Lowe, Hannah; et al. (2018). "Ground-based Optical Transmission Spectroscopy of the Small, Rocky Exoplanet GJ 1132b". The Astronomical Journal. 156 (2) 42. arXiv:1805.07328. Bibcode:2018AJ....156...42D. doi:10.3847/1538-3881/aac6dd. S2CID 119061941.
  15. ^ Swain, Mark R.; Estrela, Raissa; Roudier, Gael M.; Sotin, Christophe; Rimmer, Paul B.; Valio, Adriana; West, Robert; Pearson, Kyle; Huber-Feely, Noah; Zellem, Robert T. (2021). "Detection of an Atmosphere on a Rocky Exoplanet". The Astronomical Journal. 161 (5): 213. arXiv:2103.05657. Bibcode:2021AJ....161..213S. doi:10.3847/1538-3881/abe879. S2CID 232170188.
  16. ^ Mugnai, Lorenzo V.; Modirrousta-Galian, Darius; Edwards, Billy; Changeat, Quentin; Bouwman, Jeroen; Morello, Giuseppe; Al-Refaie, Ahmed; Baeyens, Robin; Bieger, Michelle Fabienne; Blain, Doriann; Gressier, Amélie (2021-04-05). "ARES.* V. No Evidence for Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b". The Astronomical Journal. 161 (6): 284. arXiv:2104.01873. Bibcode:2021AJ....161..284M. doi:10.3847/1538-3881/abf3c3. S2CID 233025360.
  17. ^ Libby-Roberts, Jessica E.; Berta-Thompson, Zachory K.; Diamond-Lowe, Hannah; Gully-Santiago, Michael A.; Irwin, Jonathan M.; Kempton, Eliza M.-R.; Rackham, Benjamin V.; Charbonneau, David; Desert, Jean-Michel; Dittmann, Jason A.; Hofmann, Ryan (2022). "The Featureless HST/WFC3 Transmission Spectrum of the Rocky Exoplanet GJ 1132b: No Evidence for a Cloud-free Primordial Atmosphere and Constraints on Starspot Contamination". The Astronomical Journal. 164 (2): 59. arXiv:2105.10487. Bibcode:2022AJ....164...59L. doi:10.3847/1538-3881/ac75de. S2CID 235125875.
  18. ^ Kreidburg, Laura; et al. (August 2019). "Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b". Nature. 573 (7772): 87–90. arXiv:1908.06834. Bibcode:2019Natur.573...87K. doi:10.1038/s41586-019-1497-4. PMID 31427764. S2CID 256819677.
  19. ^ Greene, Thomas P.; Bell, Taylor J.; Ducrot, Elsa; Dyrek, Achrène; Lagage, Pierre-Olivier; Fortney, Jonathan J. (March 2023). "Thermal Emission from the Earth-sized Exoplanet TRAPPIST-1 b using JWST". Nature. 618 (7963): 39–42. arXiv:2303.14849. Bibcode:2023Natur.618...39G. doi:10.1038/s41586-023-05951-7. PMID 36972683. S2CID 257767242.
  20. ^ Zieba, Sebastian; Kreidberg, Laura; Ducrot, Elsa; Gillon, Michaël; et al. (June 2023). "No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c". Nature. 620 (7975): 746–749. arXiv:2306.10150. Bibcode:2023Natur.620..746Z. doi:10.1038/s41586-023-06232-z. PMC 10447244. PMID 37337068. S2CID 259200424.
  21. ^ Mansfield, Megan Weiner; Xue, Qiao; Zhang, Michael; Mahajan, Alexandra S.; Ih, Jegug; Koll, Daniel; Bean, Jacob L.; Coy, Brandon Park; Eastman, Jason D.; Kempton, Eliza M.-R.; Kite, Edwin S.; Lunine, Jonathan (2024). "No Thick Atmosphere on the Terrestrial Exoplanet GI 486b". arXiv:2408.15123.