20217-3637 HDS2908

Coord 2000	20217-3637		Discov num	HDS2908		Comp			Coord arcsec 2000	20 21 43.04 -36 36 35.9
Date first	1991		Date last	2018		Obs	11
Pa first	108		Pa last	295		P.A. Now (θ)	100.3°
Sep first	0.1		Sep last	0.1		Sep. Now (ρ)	0.04"
Mag pri	8.25		Mag sec	8.45		delta mag (ΔM)	0.2		Spectral class	G0/G1V (yellow)
Pri motion ra	+068		Sec motion ra
Pri motion dec	-044		Sec motion dec
Notes	O (Orbital solution)

Visually invisible, K-band or other infrared star This double is physical.

Precise pa	295		Precise sep	0.071		Constellation	Sagittarius		SAO	212038
HIP	100417		Tycho2	7454-00791-1		Gaia DR2	21764909824		HD	193464
CD	CD-3713693		CP	CP-37 8776		Distance	59.38		Distance ly	193.7
last precise pa	295		last precise sep	0.071

Period (P)	12.74y	± 0.24	Periastron (T)	2007.44y	± 0.52	Semi-major axis (a)	0.112a	± 0.0065
Eccentricity (e)	0.518	± 0.046	Inclination (i)	80.8°	± 2.7	Longitude of periastron (ω)	338.9°	± 10.7
Node (Ω)	107.8°	± 0.6	Note			Grade	2	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation

label rho theta 2000 0.141 282.0 2001 0.158 284.1 2002 0.164 286.0 2003 0.158 287.8 2004 0.139 290.0 2005 0.104 293.3 2006 0.049 302.4 2007 0.027 89.7 2008 0.053 113.4 2009 0.018 163.1 2010 0.045 263.4 2011 0.088 275.5 2012 0.122 279.9 2013 0.147 282.6 2014 0.161 284.6 2015 0.164 286.4 2016 0.155 288.3 2017 0.132 290.7 2018 0.092 294.6 2019 0.032 310.4 2020 0.043 100.3 2021 0.046 118.5 2022 0.017 209.0 2023 0.057 268.3 2024 0.098 276.9 2025 0.129 280.7 2026 0.151 283.2 2027 0.163 285.1 2028 0.163 286.9 2029 0.150 288.9 2030 0.123 291.4 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
20217-3637	HDS2908		1991	1	108	0.1	8.25	8.45	G0/G1V		202143.04-363635.9
20217-3637	HDS2908		2008	4	151	0.0	8.25	8.45	G0/G1V		202143.04-363635.9
20217-3637	HDS2908		2013	7	104	0.2	8.25	8.45	G0/G1V		202143.04-363635.9
20217-3637	HDS2908		2014	8	106	0.2	8.25	8.45	G0/G1V		202143.04-363635.9
20217-3637	HDS2908		2015	9	107	0.2	8.25	8.45	G0/G1V		202143.04-363635.9
20217-3637	HDS2908		2017	10	290	0.1	8.25	8.45	G0/G1V	O	202143.04-363635.9
20217-3637	HDS2908		2018	11	295	0.1	8.25	8.45	G0/G1V	O	202143.04-363635.9

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