Chi Eridani
{{short description|Star in the constellation Eridanus}}
{{Starbox begin
| name = χ Eridani}}
{{Starbox observe
| epoch = J2000.0
| constell = Eridanus
| dec = {{DEC|−51|36|31.9736}}
| appmag_v = {{nowrap|3.70 / 10.7}}
}}
{{Starbox character
| class = G8IV or {{nowrap|G8IIIb CNIV}}
| r-i =
}}
{{Starbox astrometry
| parallax = 57.3774
| p_error = 0.3291
| absmag_v= {{nowrap|2.39 / 9.4}}
}}
{{Starbox detail
| component1 = A
| radius = {{Val|3.993|0.027}}
| luminosity = {{val|9.84|0.39}}
| temperature = {{Val|5115|49|fmt=commas}}
| gravity = {{Val|3.42|0.10}}
| metal_fe = {{Val|−0.18|0.07}}
| rotational_velocity = 4.50
| age_myr =
}}
{{Starbox catalog
| names = {{odlist | B=χ Eri | FK5=68 | GJ=81 | HD=11937 | HIP=9007 | HR=566 | SAO=232573 }}
}}
{{Starbox reference
|Simbad=chi+Eri
|ARICNS=00163|an=A
|ARICNS2=00164|an2=B
}}
{{Starbox end}}
χ Eridani (Latinised as Chi Eridani) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.70. The distance to this system, as determined using the parallax method, is around 58 light years. The pair had an angular separation of 5.0 arcseconds as of 1994. This corresponds to a projected separation of around 128 AU.
The primary component is an evolving G-type subgiant star with a stellar classification of G8 IV. It is about 1.6 times the mass of the Sun and has 4 times the Sun's radius. The star shines with 10 times the solar luminosity from its outer atmosphere at an effective temperature of 5,115 K. Unusually for a star of this class, it shows a photometric variability of 0.04 in magnitude, which may be due to a previous mass transfer from the secondary companion, or else from an undiscovered third companion.
The companion is about 7 magnitudes fainter than the primary and may be the source of the [[X-ray astronomy|X
-ray emission]] from this system. This emission has a luminosity of {{Val|504.4e27|u=erg s−1}}.
References
{{reflist|refs=
{{Cite Gaia DR2|4937200425855463936}}
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}}
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| display-authors=1
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| arxiv=astro-ph/0609258 | s2cid=16080025 | postscript=. }}
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| title=Multiplicity among F-type Stars
| journal=The Astrophysical Journal Supplement
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| doi=10.1088/0067-0049/203/2/30 | bibcode=2012ApJS..203...30F
| postscript=. | doi-access=free }}
| display-authors=1 | last1=Poveda | first1=A.
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| last1=Mermilliod | first1=J.-C.
| title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)
| journal=Catalogue of Eggen's UBV Data
| publisher=SIMBAD | date=1986 | bibcode=1986EgUBV........0M
| postscript=. }}
| title=* chi Eri -- Pre-main sequence Star
| access-date=2016-10-27 | postscript=. }}
}}
{{Stars of Eridanus|state=collapsed}}
{{DEFAULTSORT:Chi Eridani}}
Category:Eridanus (constellation)