8 Andromedae
{{Short description|Multiple star system in the constellation Andromeda}}
{{confused|Andromeda VIII}}
{{Starbox begin}}
{{Starbox image
| image=
{{Location mark
|image=Cassiopeia constellation map.svg|alt=|float=center|width=260
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=8 Andromedae
|x=826|y=776
}}
|caption=Location of 8 Andromedae (circled)
}}
{{Starbox observe
| epoch = J2000
| constell = Andromeda
| dec = {{DEC|+49|00|55.0829}}
}}
{{Starbox character
| type = AGB
| class = {{nowrap|M2.5 III Ba0.5}}
| u-b =
}}
{{Starbox astrometry
| parallax = 5.6963
| p_error = 0.1030
}}
{{Starbox detail
| source =
| mass =
| luminosity =
| temperature = {{Val|3616|22|fmt=commas}}
| metal_fe = {{Val|+0.04|0.08}}
| rotational_velocity = {{Val|5.0|1.0}}
| age_gyr =
}}
{{Starbox catalog
| names = {{odlist | F=8 And | BD=+48°3991 | FK5= | HD=219734 | HIP=115022 | HR=8860 | SAO=52871 | PPM=64030 | NSV=14484 | WDS=J23177+4901A }}
}}
{{Starbox reference
| Simbad = 8+And
}}
{{Starbox end}}
Image:8AndLightCurve.png for 8 Andromedae, plotted from Hipparcos data]]
8 Andromedae, abbreviated 8 And, is a probable triple star system in the northern constellation of Andromeda. 8 Andromedae is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.82. Based upon an annual parallax shift of {{Val|5.7|ul=mas}}, it is located about 570 light years from the Earth. It is moving closer with a heliocentric radial velocity of −8 km/s.
The primary component is an ageing red giant star with a stellar classification of {{nowrap|M2.5 III Ba0.5}}. The suffix notation indicates this is a mild barium star, which means the stellar atmosphere is enriched with s-process elements. It is either a member of a close binary system and has previously acquired these elements from a (now) white dwarf companion or else it is on the asymptotic giant branch and is generating the elements itself. This is a periodic variable of unknown type, changing in brightness with an amplitude of 0.0161 magnitude at a frequency of 0.23354 d−1, or once every 4.3 days.
The third component is the magnitude 13.0 star at an angular separation of {{Val|7.8|ul=arcsecond}} along a position angle of 164°, as of 2015. It has a Gaia Data Release 3 parallax of {{val|5.7|u=mas}} and a proper motion almost identical to 8 Andromedae. A number of other faint stars within a few arc-minutes of 8 Andromedae have been listed as companions, but none are at the same distance.
Within Andromeda it is the second of a northerly chain asterism – 11 is further south-westward, with 7, 5, then 3 Andromedae in the other direction.
References
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{{Stars of Andromeda}}
{{DEFAULTSORT:8 Andromedae}}