00219-2300 RST 5493 BC

Coord 2000	00219-2300		Discov num	RST5493		Comp	BC		Coord arcsec 2000	00 21 52.67 -23 00 23.2
Date first	1949		Date last	2021		Obs	14
Pa first	91		Pa last	92.7		P.A. Now (θ)	90.9°
Sep first	0.2		Sep last	0.129		Sep. Now (ρ)	0.173"
Mag pri	9.90		Mag sec	9.90		delta mag (ΔM)	0		Spectral class
Pri motion ra	+133		Sec motion ra	+133
Pri motion dec	-115		Sec motion dec	-115
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	HD 1766	166213	00 21 52 -23 00 28	HJ 1957 A,BC	2016	44	27	6.1	7.67	9.15	1.48
Show			00 21 53 -23 00 23	RST 5493 BC	2021	14	93	0.1	9.90	9.90	0.00	Y	<===

Triple system
4 estimated visually detectable stars in this system

Spectr	G1V		Constellation	Cetus		HIP	1732		Tycho2	6413-00769-1
Gaia DR2	2360329587101891072		HD	1766		ADS	302		CD	CD-23 111
Distance	59.49		Distance ly	194.06

Period (P)	18.44y	± 0.56	Periastron (T)	2019.53y	± 0.45	Semi-major axis (a)	0.134a	± 0.02
Eccentricity (e)	0.831	± 0.034	Inclination (i)	92.1°	± 1.7	Longitude of periastron (ω)	213.6°	± 16
Node (Ω)	91.3°	± 1.5	Notes	n		Reference	Tok2021c
Equinox	2000		Last observation	2021		Grade	3	(1=Definitive, 9=Indet.)

label theta rho 2000 67.0 0.008 2001 271.3 0.024 2002 92.2 0.069 2003 91.4 0.124 2004 91.1 0.158 2005 90.8 0.182 2006 90.6 0.198 2007 90.4 0.207 2008 90.3 0.211 2009 90.1 0.211 2010 90.0 0.207 2011 89.8 0.198 2012 89.6 0.186 2013 89.4 0.170 2014 89.1 0.150 2015 88.7 0.126 2016 88.1 0.098 2017 87.0 0.065 2018 82.9 0.026 2019 277.2 0.017 2020 93.6 0.033 2021 91.7 0.103 2022 91.2 0.145 2023 90.9 0.173 2024 90.7 0.192 2025 90.5 0.204 2026 90.4 0.210 2027 90.2 0.212 2028 90.0 0.209 2029 89.9 0.202 2030 89.7 0.192		Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st.
		Measures: green=micrometric, blue=interferometric, purple=photographic