21287+7034 LAB   6Aa,Ab

Coord 2000	21287+7034		Discov num	LAB   6		Comp	Aa,Ab		Coord arcsec 2000	21 28 39.58 +70 33 38.5
Date first	1971		Date last	2007		Obs	62
Pa first	47		Pa last	226		P.A. Now (θ)	45.9°
Sep first	0.3		Sep last	0.2		Sep. Now (ρ)	0.27"
Mag pri	3.20		Mag sec	6.60		delta mag (ΔM)	3.4		Spectral class	B2III (blue-white)
Pri motion ra	+010		Sec motion ra
Pri motion dec	+007		Sec motion dec
Notes	N O (See Notes, Orbital solution)

This double is physical.

Show	name	SAO	coord_2000	discov#	comp	first	last	obs	pa	sep	mag1	mag2	d_mag	orb	current
Show		10057	21287+7034	LAB 6	Aa,Ab	1971	2007	62	46	0.3	3.20	6.60	3.40	Y	<===
Show	Alfirk	10057	21287+7034	STF2806	AB	1779	2016	103	251	13.5	3.17	8.63	5.46

Triple system
2 visible stars in this system

Precise pa	226		Precise sep	0.172		Constellation	Cepheus		SAO	10057
HIP	106032		HD	205021		HR	8238		GC	30118
ADS	15032		Bayer	Beta Cephei		Bayer name	Bet Cep		Flamsteed	8 Cephei
Flamsteed name	8 Cep		Distance	210.08		Distance ly	685.28		last precise pa	226
last precise sep	0.172

Period (P)	83y		Periastron (T)	1997.99y		Semi-major axis (a)	0.195a
Eccentricity (e)	0.732		Inclination (i)	87.3°		Longitude of periastron (ω)	194.6°
Node (Ω)	46.4°		Note			Grade	3	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation	1998

label rho theta 2000 0.011 243.9 2001 0.016 31.7 2002 0.040 40.1 2003 0.063 42.2 2004 0.085 43.2 2005 0.104 43.8 2006 0.123 44.2 2007 0.140 44.5 2008 0.156 44.7 2009 0.171 44.9 2010 0.185 45.1 2011 0.197 45.2 2012 0.210 45.4 2013 0.221 45.5 2014 0.231 45.6 2015 0.241 45.7 2016 0.251 45.8 2017 0.259 45.9 2018 0.267 45.9 2019 0.275 46.0 2020 0.281 46.1 2021 0.288 46.1 2022 0.294 46.2 2023 0.299 46.3 2024 0.304 46.3 2025 0.308 46.4 2026 0.312 46.4 2027 0.316 46.5 2028 0.319 46.5 2029 0.322 46.6 2030 0.324 46.6 Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.
		Measures: green=micrometric, blue=interferometric, purple=photographic

coord_2000	discov_num	comp	epoch	obs	pa	sep	mag_pri	mag_sec	spectr	notes	coord_arcsec_2000
21287+7034	LAB 6	Aa,Ab	2007	62	226	0.2	3.20	6.60	B2III	N D	212839.58+703338.5

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