Astronomy:GJ 1132 b

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GJ 1132 b
Size comparison of GJ 1132 b with Earth
Discovery[3]
Discovered byMEarth-South Array Team
Discovery site Chile
Discovery dateMay 10, 2015 (announced)[1] November 12, 2015 (confirmed)[2]
Transit
Orbital characteristics[5][6]
0.01570±0.00013 astronomical unit|AU
Eccentricity0.0118+0.047
−0.0099
Orbital period1.62892911+0.00000029
−0.00000030 d
Inclination86.58°±0.63°[4]
Semi-amplitude2.98±0.30 m/s
StarGJ 1132
Physical characteristics[7]
Mean radius1.130±0.056 R🜨
Mass1.66±0.23 M🜨
Mean density6.3±1.3 g/cm3
12.9±2.2 m/s2
13.6±1.0 km/s
Albedo0.19+0.12
−0.15[5]
Physics583.8+11
−8.5 K (310.6 °C; 591.2 °F, equilibrium)[5]
709±31 K (436 °C; 817 °F, day side)[5]
Atmosphere
Composition by volumeNone or extremely thin[5]


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,[3] in the constellation Vela. The planet is considered uninhabitable but was thought to be cool enough to possess an atmosphere.[1] 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 about 13% larger than that of the Earth[3] and its mass is estimated at 1.6 times that of Earth,[1] implying that it has an Earth-like rocky composition.[12] GJ 1132 b orbits its star every 1.6 days at a distance of 2.24 million kilometres (1.4 million miles).[8]

The planet receives 19 times more stellar radiation than Earth.[3] 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][4] 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] Nevertheless, 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 and featureless.[16][17]

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.[5] Therefore, GJ 1132b likely has little to no atmosphere, consistent with the idea of the "Cosmic Shoreline"[5] 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. ↑ 1.0 1.1 1.2 Chu, Jennifer (November 11, 2015). "New exoplanet in our neighborhood". MIT News. https://news.mit.edu/2015/new-earth-sized-exoplanet-1111. 
  2. ↑ NASA Exoplanet Archive New ticker slide 1
  3. ↑ 3.0 3.1 3.2 3.3 Berta-Thompson, Zachory K. et al. (2015). "A rocky planet transiting a nearby low-mass star". Nature 527 (7577): 204–207. doi:10.1038/nature15762. PMID 26560298. Bibcode: 2015Natur.527..204B. 
  4. ↑ 4.0 4.1 Southworth, John et al. (2017). "Detection of the Atmosphere of the 1.6 M🜨 Exoplanet GJ 1132 b". The Astronomical Journal 153 (4): 191. doi:10.3847/1538-3881/aa6477. Bibcode: 2017AJ....153..191S. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Xue, Qiao; Bean, Jacob L.; Zhang, Michael; Mahajan, Alexandra S.; Ih, Jegug; Eastman, Jason D.; Lunine, Jonathan I.; Mansfield, Megan Weiner et al. (2024). "JWST Thermal Emission of the Terrestrial Exoplanet GJ 1132b". The Astrophysical Journal 973 (1): L8. doi:10.3847/2041-8213/ad72e9. Bibcode: 2024ApJ...973L...8X. 
  6. ↑ 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). doi:10.3847/1538-4365/ac9da4. Bibcode: 2023ApJS..265....4K.  Vizier catalog entry
  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, doi:10.1051/0004-6361/201731884, A142, Bibcode: 2018A&A...618A.142B. 
  8. ↑ 8.0 8.1 "Astronomers Eager to Get a Whiff of Newfound Venus-like Planet". Harvard–Smithsonian Center for Astrophysics. November 11, 2015. https://www.cfa.harvard.edu/news/2015-24. 
  9. ↑ Sample, Ian (11 November 2015). "Earth-like world could be 'most important planet found outside solar system'". https://www.theguardian.com/science/2015/nov/11/earth-like-world-gj1132b-could-be-most-important-planet-ever-found-outside-the-solar-system. 
  10. ↑ Burgess, Matt. "Exoplanet GJ 1132b: the 'most important' ever found". Wired UK. https://www.wired.co.uk/news/archive/2015-11/12/gj-1132b-most-important-planet-solar-system. Retrieved 2015-11-12. 
  11. ↑ "Getting Up Close and Personal with an Earth-Sized Exoplanet". The Kavli Foundation. November 11, 2015. http://www.kavlifoundation.org/science-spotlights/getting-close-and-personal-earth-sized-exoplanet#.VkYmYeSFMY8. 
  12. ↑ 12.0 12.1 Eva Botkin-Kowacki (2015-11-11). "Spotted: A rocky Earth-sized planet close by". The Christian Science Monitor. https://www.csmonitor.com/Science/2015/1111/Spotted-A-rocky-Earth-sized-planet-close-by. 
  13. ↑ "Atmosphere around super-Earth detected". April 6, 2017. https://phys.org/news/2017-04-atmosphere-super-earth.html. 
  14. ↑ Diamond-Lowe, Hannah et al. (2018). "Ground-based Optical Transmission Spectroscopy of the Small, Rocky Exoplanet GJ 1132b". The Astronomical Journal 156 (2). doi:10.3847/1538-3881/aac6dd. Bibcode: 2018AJ....156...42D. 
  15. ↑ Swain, Mark R.; Estrela, Raissa; Roudier, Gael M.; Sotin, Christophe; Rimmer, Paul B.; Valio, Adriana; West, Robert; Pearson, Kyle et al. (2021). "Detection of an Atmosphere on a Rocky Exoplanet". The Astronomical Journal 161 (5): 213. doi:10.3847/1538-3881/abe879. Bibcode: 2021AJ....161..213S. 
  16. ↑ Mugnai, Lorenzo V.; Modirrousta-Galian, Darius; Edwards, Billy; Changeat, Quentin; Bouwman, Jeroen; Morello, Giuseppe; Al-Refaie, Ahmed; Baeyens, Robin et al. (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. doi:10.3847/1538-3881/abf3c3. Bibcode: 2021AJ....161..284M. 
  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 et al. (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. doi:10.3847/1538-3881/ac75de. Bibcode: 2022AJ....164...59L. 
  18. ↑ Kreidburg, Laura (August 2019). "Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b". Nature 573 (7772): 87–90. doi:10.1038/s41586-019-1497-4. PMID 31427764. Bibcode: 2019Natur.573...87K. 
  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. doi:10.1038/s41586-023-05951-7. PMID 36972683. Bibcode: 2023Natur.618...39G. 
  20. ↑ Zieba, Sebastian et al. (June 2023). "No thick carbon dioxide atmosphere on the rocky exoplanet TRAPPIST-1 c". Nature 620 (7975): 746–749. doi:10.1038/s41586-023-06232-z. PMID 37337068. Bibcode: 2023Natur.620..746Z. 
  21. ↑ Mansfield, Megan Weiner; Xue, Qiao; Zhang, Michael; Mahajan, Alexandra S.; Ih, Jegug; Koll, Daniel; Bean, Jacob L.; Coy, Brandon Park et al. (2024). "No Thick Atmosphere on the Terrestrial Exoplanet GI 486b". The Astrophysical Journal 975 (1): L22. doi:10.3847/2041-8213/ad8161. Bibcode: 2024ApJ...975L..22W. 

Coordinates: Sky map 10h 14m 51.1s, −47° 09′ 12.″



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