HD 20781: Difference between revisions

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	== External links ==		== External links ==
	* {{cite encyclopedia \| url=~~http~~://exoplanet.eu/catalog/hd_20781_c/~~\| title=Planet HD 20781 c~~\| encyclopedia=] \|access-date=18 September 2020}}		* {{cite encyclopedia \| url=https://exoplanet.eu/catalog/hd_20781_c--946/\| encyclopedia=]\| title=Planet HD 20781 c\|access-date=18 September 2020}}
	* {{cite encyclopedia \| url=~~http~~://exoplanet.eu/catalog/hd_20781_b/~~\| title=Planet HD 20781 b~~\| encyclopedia=] \|access-date=18 September 2020}}		* {{cite encyclopedia \| url=https://exoplanet.eu/catalog/hd_20781_b--945/\| encyclopedia=]\| title=Planet HD 20781 b\|access-date=18 September 2020}}
	{{HD20781HD20782}}		{{HD20781HD20782}}

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	{{DEFAULTSORT:HD 20781}}		{{DEFAULTSORT:HD 20781}}
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Latest revision as of 06:22, 22 December 2023

Star in a binary star system in the constellation Fornax

HD 20781
Observation data Epoch J2000.0 Equinox J2000.0
Constellation	Fornax
Right ascension	03 20 02.94286
Declination	−28° 47′ 01.7905″
Apparent magnitude (V)	8.48
Characteristics
Spectral type	K0V
B−V color index	0.82
Astrometry

Radial velocity (R_v)	40.27±0.12 km/s
Proper motion (μ)	RA: 348.869±0.015 mas/yr Dec.: −66.614±0.019 mas/yr
Parallax (π)	27.8123 ± 0.0239 mas
Distance	117.3 ± 0.1 ly (35.96 ± 0.03 pc)
Absolute magnitude (M_V)	5.70

Details

Mass	0.7 `M`_☉
Luminosity	0.49±0.04 `L`_☉
Surface gravity (log g)	4.37±0.05 cgs
Temperature	5256±29 K
Metallicity	−0.11±0.02 dex
Rotation	46.8±4.4 d
Rotational velocity (v sin i)	1.1 km/s

Other designations
CD–29° 1229, HIP 15526, LTT 1581, SAO 168468, 2MASS J03200291-2847016, Gaia DR1 5060105892897388288
Database references
SIMBAD	data

HD 20781 is a star which is part of a wide binary system with HD 20782. The companion star has a very large angular separation of 252 arcsec, corresponding to 9080 AU at the distance of HD 20782. Both stars possess their own planetary systems in S type orbits, with a total of five known planets around both stars. This is the first known example of planets being found orbiting both components of a wide binary system. HD 20781 has no noticeable starspot activity.

Planetary system

In 2011, a pair of Neptune-mass gas giants were detected with the radial velocity method. In 2017, these planets were confirmed and an additional two inner super-Earths were detected, with periods of 5.3 and 13.9 days respectively.

The HD 20781 planetary system
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥1.93+0.39 −0.36 M_🜨	0.0529+0.0024 −0.0027	5.3135±0.0010	0.10+0.11 −0.07	—	—
c	≥5.33+0.70 −0.67 M_🜨	0.1004+0.0046 −0.0051	13.8905+0.0033 −0.0034	0.09+0.09 −0.06	—	—
d	≥10.61+1.20 −1.19 M_🜨	0.1647+0.0076 −0.0083	29.1580+0.0102 −0.0100	0.11+0.05 −0.06	—	—
e	≥14.03±1.56 M_🜨	0.3374+0.0155 −0.0170	85.5073+0.0983 −0.0947	0.06+0.06 −0.04	—	—

References

Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
^ Udry, S.; Dumusque, X.; et al. (February 2019). "The HARPS search for southern extra-solar planets. XLIV. Eight HARPS multi-planet systems hosting 20 super-Earth and Neptune-mass companions". Astronomy & Astrophysics. 622: A37. arXiv:1705.05153. Bibcode:2019A&A...622A..37U. doi:10.1051/0004-6361/201731173. S2CID 119095511.
"HD 20781 -- High proper-motion Star". SIMBAD Astronomical Database. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-10.
^ Desidera, S.; Barbieri, M. (January 2007). "Properties of planets in binary systems. The role of binary separation". Astronomy and Astrophysics. 462 (1): 345–353. arXiv:astro-ph/0610623. Bibcode:2007A&A...462..345D. doi:10.1051/0004-6361:20066319. S2CID 13813761.
"HD 20782". NASA Exoplanet Archive. Retrieved 12 November 2022.
^ Mayor, M.; Marmier, M.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 .

External links

"Planet HD 20781 c". Extrasolar Planets Encyclopaedia. Retrieved 18 September 2020.
"Planet HD 20781 b". Extrasolar Planets Encyclopaedia. Retrieved 18 September 2020.

v t e The HD 20781/HD 20782 system
HD 20781 b c d e
HD 20782 b
See also: binary stars extrasolar planets

Constellation of Fornax

Stars

Bayer	α (Dalim) β γ γ δ ε ζ η η η ι ι κ λ λ μ ν π ρ σ τ υ φ χ χ χ ψ ω
Variable	R TZ UZ
HR	683 858
HD	15337 20781 20782 20868 (Intan)
Other	2MASS J02431371−2453298 HIP 13044 LP 944-20 UDF 2457 WASP-72 (Diya)

Exoplanets	HD 16417 b HD 20781 b c d e HD 20782 b HD 20868 b (Baiduri) TOI-849 b

Star clusters	NGC 1049

Nebulae	NGC 1360

Galaxies

NGC	823 824 922 986 1097 1210 1255 1288 1310 1316 1317 1318 1326 1350 1365 1374 1375 1379 1380 1381 1387 1398 1399 1406 1425 1427
Other	Fornax Dwarf HUDF-JD2 GS-NDG-9422 IC 335 IC 1993 JADES-GS-z14-0 JADES-GS-z7-01-QU MRC 0316-257 PGC 13809 UDF 423 UDFj-39546284 UDFy-38135539

Galaxy clusters	Fornax Cluster

Astronomical events	SN 1992bd SN 1999eu SN 2003B

Latest revision as of 06:22, 22 December 2023

Planetary system

See also

References

External links