Proxima_Centauri_d References

Proxima Centauri d
	Artistic depiction of Proxima Centauri d, with Proxima Centauri and Alpha Centauri A & B visible in the background
Discovery
Discovery site	VLT- ESPRESSO
Discovery date	2020
Detection method	Radial velocity
Orbital characteristics
Semi-major axis	0.02885+0.00019; −0.00022 AU
Eccentricity	0.04+0.15; −0.04
Orbital period (sidereal)	5.122+0.002; −0.0036 d
Semi-amplitude	0.39±0.07 m/s
Star	Proxima Centauri
Physical characteristics
Mean radius	≙0.81±0.08 R🜨
Mass	≥0.26±0.05 M🜨
Temperature	360 K (87 °C; 188 °F)

Proxima Centauri d (also called Proxima d) is an exoplanet orbiting the red dwarf star Proxima Centauri, the closest star to the Sun and part of the Alpha Centauri triple star system. Together with two other planets in the Proxima Centauri system, it is the closest known exoplanet to the Solar System, located approximately 4.2 light-years (1.3 parsecs; 40 trillion kilometres; 25 trillion miles) away in the constellation of Centaurus. The first signs of the exoplanet emerged as a weak 5.15-day signal in radial velocity data taken from the Very Large Telescope during a 2020 study on Proxima b's mass. This signal was formally proposed to be a candidate exoplanet by Faria et al. in a follow-up paper published in February 2022.^[2]^[1]

Proxima d is a sub-Earth at least one-quarter of the mass of Earth (or twice the mass of Mars), orbiting at roughly 0.029 AU (4.3 million km; 2.7 million mi) every 5.1 days.^[2] It is the least massive and innermost known planet of the Proxima Centauri system. It is the least massive exoplanet detected with the radial velocity method as of 2022^[update]. Although Proxima d orbits too close to its star to have a habitable equilibrium temperature (which likely reaches 360 K (87 °C; 188 °F)^[1] from about 190% of Earth's irradiation—assuming an Earth-like reflectivity, it is theoretically possible that Proxima d possesses polar regions with habitable temperatures.

References

^ ^a ^b ^c ^d ^e Faria, J. P.; Suárez Mascareño, A.; et al. (January 4, 2022). "A candidate short-period sub-Earth orbiting Proxima Centauri" (PDF). Astronomy & Astrophysics. 658. European Southern Observatory: 17. arXiv: 2202.05188. Bibcode: 2022A&A...658A.115F. doi: 10.1051/0004-6361/202142337.
^ ^a ^b Suárez Mascareño, A.; Faria, J. P.; et al. (11 May 2020). "Revisiting Proxima with ESPRESSO". Astronomy & Astrophysics. 639: 24. arXiv: 2005.12114. Bibcode: 2020A&A...639A..77S. doi: 10.1051/0004-6361/202037745. ISSN 0004-6361.

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[Faria2022-1] Faria, J. P.; Suárez Mascareño, A.; et al. (January 4, 2022). "A candidate short-period sub-Earth orbiting Proxima Centauri" (PDF). Astronomy & Astrophysics. 658. European Southern Observatory: 17. arXiv: 2202.05188. Bibcode: 2022A&A...658A.115F. doi: 10.1051/0004-6361/202142337.

[SuarezMascareno2020-2] Suárez Mascareño, A.; Faria, J. P.; et al. (11 May 2020). "Revisiting Proxima with ESPRESSO". Astronomy & Astrophysics. 639: 24. arXiv: 2005.12114. Bibcode: 2020A&A...639A..77S. doi: 10.1051/0004-6361/202037745. ISSN 0004-6361.

[1]

[2]

v t e The Alpha Centauri system
Stars	Rigil Kentaurus (A) Toliman (B) Proxima Centauri (C)
Planets	Ab? Bb^† Bc? Cd Cb Cc?
Proposed mission concepts	2069 Alpha Centauri mission AIMStar Breakthrough Starshot Project Longshot Starlight
^† - Disproven Category

Discovery^[1]
Artistic depiction of Proxima Centauri d, with Proxima Centauri and Alpha Centauri A & B visible in the background
Discovery site	VLT- ESPRESSO
Discovery date	2020
Detection method	Radial velocity
Orbital characteristics^[1]
Semi-major axis	0.02885+0.00019 −0.00022 AU
Eccentricity	0.04+0.15 −0.04
Orbital period (sidereal)	5.122+0.002 −0.0036 d
Semi-amplitude	0.39±0.07 m/s
Star	Proxima Centauri
Physical characteristics^[1]
Mean radius	≙0.81±0.08 R_🜨
Mass	≥0.26±0.05 M_🜨
Temperature	360 K (87 °C; 188 °F)

See also

References