Gliese 433

Gliese 433 is a dim red dwarf star in the constellation of Hydra, roughly 29.5 light years away from the Sun. Astronomers have announced the discovery of a super-Earth extrasolar planet in close orbit.

Gliese 433
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Hydra
Right ascension  11h 35m 26.9485s
Declination −32° 32′ 23.900″
Apparent magnitude (V) 9.79
Characteristics
Spectral type M1.5V
Apparent magnitude (U) 12.508
Apparent magnitude (B) 11.28
Apparent magnitude (R) 8.821
Apparent magnitude (I) 7.664
Apparent magnitude (J) 6.471
Apparent magnitude (H) 5.856
Apparent magnitude (K) 5.623
U−B color index 1.23
B−V color index 1.49
V−R color index 0.97
R−I color index 1.157
Astrometry
Proper motion (μ) RA:  –69.85 mas/yr
Dec.:  –852.54 mas/yr
Parallax (π)109.57 ± 0.38 mas
Distance29.8 ± 0.1 ly
(9.13 ± 0.03 pc)
Absolute magnitude (MV)10.01
Details
Mass0.48[1] M☉
Radius0.48±0.01 R☉
Luminosity0.033±0.002 L☉
Habitable zone inner limit0.186[2] AU
Habitable zone outer limit0.362[2] AU
Surface gravity (log g)4.42 cgs
Temperature3,550±100 K
Metallicity−0.02±0.05[3]
Rotation73.2±16.0 d[4]
Other designations
HIP 56528, GJ 433, CD-31 9113, LHS 2429, LTT 4290, NLTT 27914, SAO 202602
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data
Data sources:
Hipparcos Catalogue,
CCDM (2002),
Bright Star Catalogue (5th rev. ed.)

Planetary system

Gliese 433 b is an extrasolar planet which orbits the star Gliese 433. This planet is a super-Earth with at least six times the mass of Earth and takes approximately seven days to orbit the star at a semimajor axis of approximately 0.056 AU. The planet was announced in a press release in October 2009, but no discovery paper at the time was made available.[5] A study described in a 2014 paper by Tuomi et al. confirmed both Gliese 433 b and another candidate planet, previously detected in 2012, Gliese 433 c.[6]

Gliese 433 d, whose discovery was published in January 2020, is very similar in mass to Gliese 433 b but orbits slightly further out, actually within the optimistic habitable zone of the star, but it is still too close to the star, and therefore too warm, to be inside the narrower boundaries of the conservative habitable zone.[2][7]

Gliese 433 c orbits the furthest out from the star. To date it is the nearest, widest orbiting, and coldest Neptune-like planet yet detected. It is also notable in having an unusually eccentric orbit for a large planet so far from its parent single star and other planets.[7]

Diagram of the (probable) Gliese 433 Star system.
The Gliese 433 planetary system[7]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >6.0 M⊕ 0.054 7.0 0.08 — —
Gliese 433 d 5.223 ± 0.921 M⊕ 0.178 ± 0.006 36.059 ± 0.016 0.07 ± 0.05 — —
c (unconfirmed) ≥28.78+19.15
−10.46 M⊕		 4.692+1.169
−0.768		 4,873.923+1,796.128
−1,034.762		 0.21+0.08
−0.21		 — —
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See also

References
  1. Zechmeister, M.; Kürster, M.; Endl, M. (August 6, 2009). "The M dwarf planet search programme at the ESO VLT + UVES. A search for terrestrial planets in the habitable zone of M dwarfs". Astronomy and Astrophysics. 505: 859–871. arXiv:0908.0944. Bibcode:2009A&A...505..859Z. doi:10.1051/0004-6361/200912479.
  2. "PHL's Exoplanets Catalog". University of Puerto Rico at Arecibo. 5 December 2019. Retrieved 26 January 2020.
  3. Lindgren, Sara; Heiter, Ulrike (2017). "Metallicity determination of M dwarfs. Expanded parameter range in metallicity and effective temperature". Astronomy and Astrophysics. 604: A97. arXiv:1705.08785. Bibcode:2017A&A...604A..97L. doi:10.1051/0004-6361/201730715.
  4. Suárez Mascareño, A.; et al. (September 2015), "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators", Monthly Notices of the Royal Astronomical Society, 452 (3): 2745–2756, arXiv:1506.08039, Bibcode:2015MNRAS.452.2745S, doi:10.1093/mnras/stv1441.
  5. "32 New Exoplanets Found". ESO News. ESO. Retrieved 15 February 2012.
  6. Tuomi, Mikko; Jones, Hugh R. A.; Barnes, John R.; et al. (2014). "Bayesian search for low-mass planets around nearby M dwarfs – estimates for occurrence rate based on global detectability statistics". Monthly Notices of the Royal Astronomical Society. 441 (2): 1545–1569. arXiv:1403.0430. Bibcode:2014MNRAS.441.1545T. doi:10.1093/mnras/stu358. ISSN 1365-2966.
  7. Feng, Fabo; Butler, R. Paul; Shectman, Stephen A.; et al. (2020). "Search for Nearby Earth Analogs. II. Detection of Five New Planets, Eight Planet Candidates, and Confirmation of Three Planets around Nine Nearby M Dwarfs". The Astrophysical Journal Supplement Series. 246 (1): 38. arXiv:2001.02577. Bibcode:2020ApJS..246...11F. doi:10.3847/1538-4365/ab5e7c. ISSN 1538-4365. 11.


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