4 Cassiopeiae
{{short description|Star in the constellation Cassiopeia}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = A light curve for 4 Cassiopeiae, plotted from Hipparcos data. The assumed period is from Koen and Eyer (2002).
}}
{{Starbox observe
| epoch = J2000.0
| constell = Cassiopeia
| dec = {{DEC|+62|16|58.1094}}
| appmag_v = {{nowrap|4.96 (4.95{{snd}}5.00)}}
}}
{{Starbox character
| type = AGB
}}
{{Starbox astrometry
| radial_v = {{Val|−38.99|0.23}}
| parallax = 4.15
| p_error = 0.21
}}
{{Starbox detail
| source =
| gravity =
| metal_fe =
| rotational_velocity =
| age_myr =
}}
{{Starbox catalog
| names = {{odlist | F=4 Cas | BD=+61°2444 | FK5=882 | HD=220652 | HIP=115590 | HR=8904 | NSV=14549 | SAO=20614 | WDS=J23248+6217A }}
}}
{{Starbox reference
| Simbad = 4+Cas
}}
{{Starbox end}}
File:Messier 52 M52 NGC 7654 Cassiopeia, with a TSAPO65Q (51668515734).jpg, with the bright star 4 Cassiopeiae on the right (north) edge of the image]]
4 Cassiopeiae is a red giant in the northern constellation of Cassiopeia, located approximately 790 light-years away from the Sun. It is visible to the naked eye as a faint, red-hued star with a baseline apparent visual magnitude of 4.96. At the distance of this system, its visual magnitude is diminished by an extinction of 0.56 due to interstellar dust. This system is moving closer to the Earth with a heliocentric radial velocity of −39 km/s.
An evolved red giant star, currently on the asymptotic giant branch, 4 Cassiopeiae has a stellar classification of M2− IIIab. It is a suspected variable star of unknown type with a brightness that varies from visual magnitude 4.95 down to 5.00.
Multiple star catalogues list a number of companions to 4 Cassiopeiae, all unrelated stars at different distances. As of 2011, the magnitude 9.88 component B lay at an angular separation of {{Val|96.10|ul=arcsecond}} along a position angle of 226° relative to the primary. Components C, E, F, and G are all fainter and more than two arc-minutes from 4 Cassiopeiae, and components C and G are themselves close doubles.
4 Cassiopeiae is 40' north of the open cluster Messier 52, near the constellation border with Cepheus, although it is not a member of the cluster.
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References
{{reflist|refs=
{{cite simbad | title=4 Cas | access-date=2019-04-13 }}
{{cite Gaia DR2|2016497560776127104}}
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| title=New periodic variables from the Hipparcos epoch photometry
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| doi=10.1046/j.1365-8711.2002.05150.x | arxiv=astro-ph/0112194 | bibcode=2002MNRAS.331...45K
| s2cid=10505995 | doi-access=free }}
| title=Light Curve
| url=https://www.cosmos.esa.int/web/hipparcos/java-tools/light-curve
| website=Hipparcos ESA | publisher=ESA | access-date=3 October 2022}}
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| doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869
}}
| display-authors=1 | last1=Mason | first1=B. D.
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| journal=The Astronomical Journal | year=2014 | volume=122 | issue=6 | page=3466 | bibcode=2001AJ....122.3466M
| postscript=. | doi=10.1086/323920 | doi-access=free }}
| display-authors=1 | last1=Famaey | first1=B.
| last2=Jorissen | first2=A. | last3=Luri | first3=X.
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| last6=Dejonghe | first6=H. | last7=Turon | first7=C.
| title=Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
| journal=Astronomy and Astrophysics
| volume=430 | issue=1 | pages=165–186 | date=January 2005
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| arxiv=astro-ph/0409579 | s2cid=17804304 | postscript=. }}
}}
{{Stars of Cassiopeia}}