f Eridani
{{short description|Multiple star system in the constellation Eridanus}}
{{lowercasetitle}}
{{Starbox begin
| name = HD 24071 and HD 24072
}}
{{Starbox image
| image=
{{Location mark
|image=Eridanus constellation map.svg|alt=|float=center|width=260
|label=|position=right
|mark=Red circle.svg|mark_width=8|mark_link=HD 24160
|x=496|y=750
}}
|caption=Location of HD 24160 (circled)
}}
{{Starbox observe 2s
| epoch = J2000
| constell = Eridanus
| component1 = HD 24072
| dec1 = {{DEC|−37|37|12.5158}}
| appmag_v1 = {{val|4.721|0.009}}
| component2 = HD 24071
| dec2 = {{DEC|−37|37|19.2124}}
| appmag_v2 = {{val|5.246|0.009}}
}}
{{Starbox character
| component1 = HD 24072
| b-v =
| component2 = HD 24071
| b-v2 =
}}
{{Starbox astrometry
| component1 = HD 24072
| radial_v =
| parallax = 18.8093
| p_error = 0.2220
| absmag_v = {{val|1.194|0.190}}
| component2 = HD 24071
| radial_v2 =
| parallax2 = 18.7976
| p_error2 = 0.0582
| absmag_v2 = {{val|1.719|0.190}}
}}
{{Starbox detail
| source =
| component1 = HD 24072
| component2 = HD 24071
}}
{{Starbox catalog
| names = {{odlist | B=f Eridani | CD=−38 1297 | HIP=17797 | WDS=J03486-3737 }}
| component1 = HD 24072
| names1 = {{odlist | HR=1190 | SAO=194551}}
| component2 = HD 24071
| names2 = {{odlist | HR=1189 | SAO=194550 }}
}}
{{Starbox reference
| Simbad = HIP+17797
| Simbad2 = HD+24072|sn2=HD 24072
| Simbad3 = HD+24071|sn3=HD 24071
}}
{{Starbox end}}
f Eridani is a binary, or possibly a triple, star system in the equatorial constellation of Eridanus, consisting of stars HD 24071 and HD 24072. They share a single Hipparcos catalogue entry, HIP 17797, but have separate Bright Star Catalogue listings, HR 1189 and 1190. f Eridani is the Bayer designation of the pair.
f Eridani is visible to the naked eye as a single star with a magnitude of 4.25. HD 24071 has an apparent visual magnitude of 5.25 and HD 24072 a magnitude of 4.72. As of 2009, the pair had an angular separation of {{Val|8.40|ul=arcsecond}} along a position angle of 216°. Both stars have an annual parallax shift {{Val|18.8|ul=mas}}, which provides a distance estimate to the system of 173 light years. The pair are members of the Tucana-Horologium moving group, a 45 million year old set of stars that share a common motion through space.
The brighter component, HD 24072, is a B-type main-sequence star with a classification of B9.5 Van. The n suffix indicates "nebulous" absorption lines which are caused by its rapid rotation. It has a projected rotational velocity of 225 km/s.
HD 24071 may itself be a spectroscopic binary. The visible component is an A-type main-sequence star with a stellar classification of A1 Va. It is a suspected variable star of unknown type showing an amplitude of 0.05 magnitude, and is a source of X-ray emission, which may originate from a companion of class G2-5V.
References
{{reflist|refs=
{{cite simbad | title=HD 24072 | access-date=2018-07-22 }}
{{cite simbad | title=HD 24071 | access-date=2018-07-22 }}
{{cite Gaia DR3|4856719713756945664}}
{{cite Gaia DR3|4856719713756946176}}
| title=A catalogue of multiplicity among bright stellar systems
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=389 | issue=2 | page=869 | date=2008
| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | postscript=.
| bibcode=2008MNRAS.389..869E | arxiv=0806.2878 | s2cid=14878976 }}
| title=The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation
| last1=Gray | first1=R. O. | last2=Garrison | first2=R. F.
| journal=Astrophysical Journal Supplement
| volume=65 | page=581 | date=December 1987
| doi=10.1086/191237 | bibcode=1987ApJS...65..581G | doi-access=free }}
| title=A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood
| display-authors=1 | last1=Bell | first1=Cameron P. M.
| last2=Mamajek | first2=Eric E. | last3=Naylor | first3=Tim
| journal=Monthly Notices of the Royal Astronomical Society
| volume=454 | issue=1 | pages=593–614 | date=November 2015
| doi=10.1093/mnras/stv1981 | doi-access=free | bibcode=2015MNRAS.454..593B
| arxiv=1508.05955 | s2cid=55297862 | postscript=. }}
| display-authors=1 | last1=Royer | first1=F.
| last2=Grenier | first2=S. | last3=Baylac | first3=M.-O.
| last4=Gómez | first4=A. E. | last5=Zorec | first5=J.
| title=Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
| journal=Astronomy and Astrophysics
| volume=393 | pages=897–911 |date=October 2002
| doi=10.1051/0004-6361:20020943 | bibcode=2002A&A...393..897R
| arxiv=astro-ph/0205255 | s2cid=14070763 | postscript=. }}
| title=X-ray emission from A-type stars
| last1=Schröder | first1=C. | last2=Schmitt | first2=J. H. M. M.
| journal=Astronomy and Astrophysics | postscript=.
| volume=475 | issue=2 | date=November 2007 | pages=677–684
| doi=10.1051/0004-6361:20077429 | bibcode=2007A&A...475..677S | doi-access=free }}
| title=On the Variability of A0-A2 Luminosity Class III-V Stars
| display-authors=1 | last1=Adelman | first1=S. J.
| last2=Flores | first2=R. S. C. Jr. | last3=Patel | first3=V. J.
| journal=Information Bulletin on Variable Stars
| volume=4984 | page=1 | date=November 2000
| bibcode=2000IBVS.4984....1A | postscript=. }}
| display-authors=1 | last1=Mason | first1=B. D.
| last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I.
| last4=Douglass | first4=G. G. | last5=Worley | first5=C. E.
| title=The Washington Visual Double Star Catalog
| journal=The Astronomical Journal | year=2014 | volume=122 | issue=6 | page=3466 | bibcode=2001AJ....122.3466M
| doi=10.1086/323920 | doi-access=free }}
}}
{{Stars of Eridanus}}
{{DEFAULTSORT:HD 24071}}
Category:Eridanus (constellation)
Category:Durchmusterung objects