HD 225218

HD 225218
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Andromeda
	HD 225218 A
Right ascension	00h 04m 36.58441s
Declination	+42° 05′ 33.0865″
Apparent magnitude (V)	6.16
	HD 225218 B
Right ascension	00h 04m 36.67195s
Declination	+42° 05′ 27.8497″
Apparent magnitude (V)	9.65
Characteristics
A
Spectral type	B9III
U−B color index	0.14[citation needed]
B−V color index	0.15[citation needed]
A
Evolutionary stage	main sequence
Spectral type	F0V
Astrometry
HD 225218 A
Radial velocity (Rv)	−8.0 km/s
Proper motion (μ)	RA: −10.367±0.266 mas/yr ; Dec.: −14.491±0.222 mas/yr
Parallax (π)	3.0041±0.3539 mas
Distance	approx. 1,100 ly ; (approx. 330 pc)
HD 225218 B
Proper motion (μ)	RA: −12.314±0.015 mas/yr ; Dec.: −16.129±0.015 mas/yr
Parallax (π)	4.4324±0.0208 mas
Distance	736 ± 3 ly ; (226 ± 1 pc)
Orbit
Primary	Aa
Name	Ab
Period (P)	70.12 yr
Semi-major axis (a)	0.165″
Eccentricity (e)	0.515
Longitude of the node (Ω)	100.6°
Periastron epoch (T)	B2050.0701
Argument of periastron (ω); (secondary)	295.1°
Details
Aa
Mass	4.02 M☉
Radius	10.6 R☉
Luminosity	394 L☉
Surface gravity (log g)	3.90 cgs
Temperature	7,679 K
Rotation	25
Age	1.52 years
Ab
Mass	2.01 M☉
B
Mass	1.34 M☉
Radius	1.58 R☉
Luminosity	4.10 L☉
Surface gravity (log g)	4.17 cgs
Temperature	6,529 K
Age	2.75 Gyr
Other designations
	BD+41 4933, HD 225218, HIP 365, HR 9105, NSV 15012, SAO 36037, WDS J00046+4206
Database references
SIMBAD	A
	B

HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III,^[5] an apparent magnitude of 6.16,^[3] and is a candidate Lambda Boötis star.^[13] It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°.^[3] The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515.^[14] Component B is has been suspected to itself be a spectroscopic binary,^[13] but it is now thought that component A contains a third low-mass star.^[8]

Apparentmagnitude(V)6.16^[3]

Apparentmagnitude(V)9.65^[3]

SpectraltypeB9III^[5]

U−B color index0.14^{[citation needed]}

Quick facts Observation data Epoch J2000.0 Equinox J2000.0, Apparent magnitude (V) ...

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Observation data Epoch J2000.0 Equinox J2000.0
Constellation	Andromeda^[1]
HD 225218 A
Right ascension	00^h 04^m 36.58441^s^[2]
Declination	+42° 05′ 33.0865″^[2]
Apparent magnitude (V)	6.16^[3]
HD 225218 B
Right ascension	00^h 04^m 36.67195^s^[4]
Declination	+42° 05′ 27.8497″^[4]
Apparent magnitude (V)	9.65^[3]
Characteristics
A
Spectral type	B9III^[5]
U−B color index	0.14^{[citation needed]}
B−V color index	0.15^{[citation needed]}
A
Evolutionary stage	main sequence^[4]
Spectral type	F0V^[6]
Astrometry
HD 225218 A
Radial velocity (R_v)	−8.0^[7] km/s
Proper motion (μ)	RA: −10.367±0.266^[2] mas/yr Dec.: −14.491±0.222^[2] mas/yr
Parallax (π)	3.0041±0.3539 mas^[2]
Distance	approx. 1,100 ly (approx. 330 pc)
HD 225218 B
Proper motion (μ)	RA: −12.314±0.015^[4] mas/yr Dec.: −16.129±0.015^[4] mas/yr
Parallax (π)	4.4324±0.0208 mas^[4]
Distance	736 ± 3 ly (226 ± 1 pc)
Orbit^[8]
Primary	Aa
Name	Ab
Period (P)	70.12 yr
Semi-major axis (a)	0.165″
Eccentricity (e)	0.515
Longitude of the node (Ω)	100.6°
Periastron epoch (T)	B2050.0701
Argument of periastron (ω) (secondary)	295.1°
Details
Aa
Mass	4.02^[8] `M`_☉
Radius	10.6^[9] `R`_☉
Luminosity	394^[10] `L`_☉
Surface gravity (log g)	3.90^[11] cgs
Temperature	7,679^[11] K
Rotation	25^[12]
Age	1.52^[11] years
Ab
Mass	2.01^[8] `M`_☉
B
Mass	1.34^[9] `M`_☉
Radius	1.58^[9] `R`_☉
Luminosity	4.10^[9] `L`_☉
Surface gravity (log g)	4.17^[9] cgs
Temperature	6,529^[9] K
Age	2.75^[4] Gyr

Other designations
BD+41 4933, HD 225218, HIP 365, HR 9105, NSV 15012, SAO 36037, WDS J00046+4206
Database references
SIMBAD	A
	B

HD 225218

References

External links

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