20216+1930 COU 327AB

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		P.A. Now (θ)	247.1°
Sep first	0.2		Sep last	0.2		Sep. Now (ρ)	0.16"
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	247	0.2	9.10	9.10	0.00	Y	<===
Show		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 visible stars in this system

Precise pa	245.1		Precise sep	0.177		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		last precise pa	245.1
last precise sep	0.177

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	Note			Grade	3	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation	2005

label rho theta 2000 0.039 220.7 2001 0.051 227.2 2002 0.064 231.2 2003 0.076 233.9 2004 0.087 235.9 2005 0.099 237.4 2006 0.109 238.6 2007 0.119 239.6 2008 0.129 240.5 2009 0.138 241.2 2010 0.146 241.9 2011 0.153 242.5 2012 0.159 243.0 2013 0.165 243.5 2014 0.169 244.0 2015 0.172 244.4 2016 0.174 244.8 2017 0.175 245.3 2018 0.174 245.7 2019 0.171 246.1 2020 0.167 246.6 2021 0.160 247.1 2022 0.151 247.6 2023 0.138 248.2 2024 0.122 249.0 2025 0.102 250.0 2026 0.076 251.7 2027 0.045 255.4 2028 0.009 288.9 2029 0.032 59.6 2030 0.062 66.0		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
20216+1930	COU 327	AB	2005	20	238	0.1	9.10	9.10	F8	NOD	202135.69+192940.1
20216+1930	COU 327	AB	2007	21	170	0.1	9.10	9.10	F8	NOD	202135.69+192940.1
20216+1930	COU 327	AB	2018	22	245	0.2	9.10	9.10	F8	NO	202135.69+192940.1
20216+1930	COU 327	AB	2019	23	245	0.2	9.10	9.10	F8	NO	202135.69+192940.1

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