20239-4225 BU  763AB (Kap2 Sgr)

Coord 2000	20239-4225		Discov num	BU  763		Comp	AB		Coord arcsec 2000	20 23 53.17 -42 25 22.2
Date first	1874		Date last	2017		Obs	54
Pa first	225		Pa last	174		P.A. Now (θ)	356.2°
Sep first	1.5		Sep last	0.4		Sep. Now (ρ)	0.46"
Mag pri	5.67		Mag sec	7.25		delta mag (ΔM)	1.58		Spectral class	A5V (white)
Pri motion ra	-006		Sec motion ra	-006
Pri motion dec	+024		Sec motion dec	+024
Notes	N O (See Notes, Orbital solution)

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

Show	name	SAO	coord_2000	discov#	comp	first	last	obs	pa	sep	mag1	mag2	d_mag	orb	current
Show	Kap2 Sgr	230184	20239-4225	BU 763	AB	1874	2017	54	356	0.5	5.67	7.25	1.58	Y	<===
Show		230184	20239-4225	I 1626	AC	1925	1998	2	268	18.6	5.67	14.30	8.63
Show		230184	20239-4225	SEE 511	AD	1897	2000	4	219	29.8	5.67	14.00	8.33

Quadruple system
4 visible stars in this system

Precise pa	174		Precise sep	0.414		Name	Kap2 Sgr		Constellation	Sagittarius
SAO	230184		HIP	100591		Tycho2	7957-01410-1		Gaia DR2	21813065856
HD	193807		HR	7787		GC	28341		CD	CD-4214847
CP	CP-42 9068		Bayer	Kappa 2 Sagittarii		Bayer name	Kap2 Sgr		Distance	95.51
Distance ly	311.55		last precise pa	174		last precise sep	0.414

Period (P)	700y		Periastron (T)	1912y		Semi-major axis (a)	2.032a
Eccentricity (e)	0.401		Inclination (i)	80°		Longitude of periastron (ω)	177.3°
Node (Ω)	40.7°		Note			Grade	5	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation	1992

label rho theta 2000 0.307 295.1 2001 0.304 298.8 2002 0.302 302.4 2003 0.301 306.2 2004 0.302 309.9 2005 0.303 313.6 2006 0.306 317.2 2007 0.310 320.8 2008 0.316 324.2 2009 0.322 327.6 2010 0.329 330.7 2011 0.337 333.8 2012 0.346 336.7 2013 0.356 339.4 2014 0.367 342.0 2015 0.378 344.4 2016 0.390 346.7 2017 0.403 348.9 2018 0.415 350.9 2019 0.429 352.8 2020 0.443 354.6 2021 0.457 356.2 2022 0.471 357.8 2023 0.486 359.3 2024 0.501 0.7 2025 0.516 2.0 2026 0.531 3.2 2027 0.547 4.4 2028 0.563 5.5 2029 0.579 6.5 2030 0.595 7.5 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
20239-4225	BU 763	AB	1992	47	268	0.4	5.93	7.25	A5V	NOD	202353.19-422522.5
20239-4225	BU 763	AB	2008	48	317	0.2	5.93	7.25	A5V	NOD	202353.19-422522.5
20239-4225	BU 763	AB	2013	50	345	0.3	5.67	7.25	A5V	NO	202353.17-422522.2
20239-4225	BU 763	AB	2016	53	352	0.4	5.67	7.25	A5V	NO	202353.17-422522.2
20239-4225	BU 763	AB	2017	54	174	0.4	5.67	7.25	A5V	NO	202353.17-422522.2

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