61 Cancri
{{Short description|Star in the constellation Cancer}}
{{Starbox begin
| name = 61 Cancri
}}
{{Starbox observe
| epoch = J2000.0
| equino = J2000.0
| constell = Cancer
| dec = {{DEC|+30|14|01.7715}}
| appmag_v = +6.290 {{nowrap|(7.0 + 7.0)}}
}}
{{Starbox character
| variable =
}}
{{Starbox astrometry
| radial_v = {{Val|+10.1|0.3}}
| parallax = 18.01
| p_error = 0.52
| absmag_v =
}}
{{Starbox detail
| source =
| component1 = 61 Cnc A
| radius =
| luminosity =
| component2 = 61 Cnc B
}}
{{Starbox catalog
| names = 61 Cancri, BD+30°1795, HD 76572, HIP 44031, HR 3563, SAO 61157.
}}
{{Starbox reference
| Simbad = 61+Cnc
}}
{{Starbox end}}
61 Cancri (61 Cnc) is the Flamsteed designation for a visual binary star system in the northern constellation Cancer. The pair have a combined apparent magnitude of 6.25, which means 61 Cancri is faintly visible to the naked eye. (According to the Bortle scale, it can be seen from rural or even dark suburban skies.) Based upon parallax measurements, the system is approximately 181 light years away from Earth.
The two components appear to be roughly identical with individual masses of about 1.4 times that of the Sun and apparent magnitudes of 7.0. Their combined stellar classification is F4V, matching that of an F-type main sequence star. They have an angular separation of 0.300″ along a position angle of 129.0° (as of 2014). The pair orbit each other with an estimated period of 40.657 years. No significant level of chromospheric activity has been detected coming from either star.
References
{{Reflist|refs=
| title=Validation of the new Hipparcos reduction
| last1=van Leeuwen | first1=F.
| journal=Astronomy and Astrophysics
| volume=474 | issue=2 | pages=653–664 | year=2007
| arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357
| s2cid=18759600 }}
| last1=Abt | first1=Helmut A.
| title=Visual Multiples. IX. MK Spectral Types
| journal=The Astrophysical Journal Supplement Series
| volume=176 | issue=1 | pages=216–217 | date=May 2008
| doi=10.1086/525529 | bibcode=2008ApJS..176..216A | postscript=. | doi-access=free }}
| display-authors=1 | last1=Nordström | first1=B.
| last2=Mayor | first2=M. | last3=Andersen | first3=J.
| last4=Holmberg | first4=J. | last5=Pont | first5=F.
| last6=Jørgensen | first6=B. R. | last7=Olsen | first7=E. H.
| last8=Udry | first8=S. | last9=Mowlavi | first9=N.
| title=The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14000 F and G dwarfs
| journal=Astronomy and Astrophysics
| volume=418 | pages=989–1019 | date=May 2014
| doi=10.1051/0004-6361:20035959 | bibcode=2004A&A...418..989N
| arxiv=astro-ph/0405198 | s2cid=11027621 | postscript=. }}
| last1=Bernacca | first1=P. L. | last2=Perinotto | first2=M.
| title=A catalogue of stellar rotational velocities.
| journal=Contributi Osservatorio Astronomico di Padova in Asiago
| date=1970 | volume= 239
| page=1 | bibcode=1970CoAsi.239....1B | postscript=. }}
| title=From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs
| last1=Tokovinin | first1=Andrei
| journal=The Astronomical Journal
| volume=147 | issue=4 | id=87 | pages=14 | date=April 2014
| doi=10.1088/0004-6256/147/4/87 | bibcode=2014AJ....147...87T
| arxiv=1401.6827 | s2cid=56066740 | postscript=. }}
| title=Patterns of Variation among Sun-like Stars
| last1=Radick | first1=Richard R. | last2=Lockwood | first2=G. W.
| last3=Skiff | first3=B. A. | last4=Baliunas | first4=S. L.
| journal=The Astrophysical Journal Supplement Series
| volume=118 | issue=1 | pages=239–258 | date=September 1998
| doi=10.1086/313135 | bibcode=1998ApJS..118..239R
| postscript=. | doi-access=free }}
| last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A.
| title=The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
| journal=The Astrophysical Journal
| volume=804 | issue=2 | id=146 | pages=38 | date=May 2015
| doi=10.1088/0004-637X/804/2/146
| bibcode=2015ApJ...804..146D
| arxiv=1501.03154 | s2cid=33401607 | postscript=. }}
| last1=Mermilliod | first1=J.-C.
| title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)
| journal=Catalogue of Eggen's UBV Data | date=1986
| bibcode=1986EgUBV........0M | postscript=. }}
| title=* 61 Cnc }}
}}
{{Stars of Cancer}}
{{DEFAULTSORT:61 Cancri}}
Category:F-type main-sequence stars
Category:Cancer (constellation)