20216+1930 COU 327 AB

Coord 2000	20216+1930		Discov num	COU 327		Comp	AB		Coord arcsec 2000	20 21 35.69 +19 29 40.1
Date first	1968		Date last	2019		Obs	24
Pa first	72		Pa last	245.1		P.A. Now (θ)	248.2°
Sep first	0.2		Sep last	0.177		Sep. Now (ρ)	0.138"
Mag pri	9.10		Mag sec	9.10		delta mag (ΔM)	0		Spectral class	F8 (yellow-white)
Pri motion ra	+009		Sec motion ra
Pri motion dec	+001		Sec motion dec
Notes	N O (See Notes, Orbital solution)

This double is physical.

Show	name	SAO	coord	wds_name	last	obs	pa	sep	mag1	mag2	d_mag	orb	current
Show		106021	20 21 36 +19 29 40	COU 327 AB	2019	24	245	0.2	9.10	9.10	0.00	Y	<===
Show	HD 193797	106021	20 21 36 +19 29 40	COU 327 AB,C	2011	7	132	4.1	8.41	11.97	3.56

Triple system
4 estimated visually detectable stars in this system

Constellation	Delphinus		SAO	106021		HIP	100397		Tycho2	1639-02397-1
Gaia DR2	1816309371324521728		HD	193797		BD	BD+19 4380		Distance	188.68
Distance ly	615.47

Period (P)	42.46y	± 1	Periastron (T)	1986.6y	± 0.1	Semi-major axis (a)	0.147a	± 0.002
Eccentricity (e)	0.577	± 0.003	Inclination (i)	85°	± 0.5	Longitude of periastron (ω)	303°	± 1
Node (Ω)	68°	± 0.5	Notes	n		Reference	Doc2008a
Equinox	2000		Last observation	2005		Grade	3	(1=Definitive, 9=Indet.)

label theta rho 2000 220.7 0.039 2001 227.2 0.051 2002 231.2 0.064 2003 233.9 0.076 2004 235.9 0.087 2005 237.4 0.099 2006 238.6 0.109 2007 239.6 0.119 2008 240.5 0.129 2009 241.2 0.138 2010 241.9 0.146 2011 242.5 0.153 2012 243.0 0.159 2013 243.5 0.165 2014 244.0 0.169 2015 244.4 0.172 2016 244.8 0.174 2017 245.3 0.175 2018 245.7 0.174 2019 246.1 0.171 2020 246.6 0.167 2021 247.1 0.160 2022 247.6 0.151 2023 248.2 0.138 2024 249.0 0.122 2025 250.0 0.102 2026 251.7 0.076 2027 255.4 0.045 2028 288.9 0.009 2029 59.6 0.032 2030 66.0 0.062		Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.
		Measures: green=micrometric, blue=interferometric, purple=photographic