00251+4803 HDS  56AB

Coord 2000	00251+4803		Discov num	HDS  56		Comp	AB		Coord arcsec 2000	00 25 08.74 +48 02 51.0
Date first	1991		Date last	2013		Obs	17
Pa first	242		Pa last	273		P.A. Now (θ)	231.5°
Sep first	0.3		Sep last	0.3		Sep. Now (ρ)	0.26"
Mag pri	7.72		Mag sec	10.63		delta mag (ΔM)	2.91		Spectral class	F8 (yellow-white)
Pri motion ra	+274		Sec motion ra
Pri motion dec	+011		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		36347	00 25 09 +48 02 51	HDS 56 AB	2013	17	232	0.3	7.72	10.63	2.91	Y	<===
Show		36347	00 25 09 +48 02 51	CRZ 2 AC	2015	2	193	121.2	7.53	14.70	7.17
Show		36347	00 25 09 +48 02 51	SOZ 4 AB,D	2015	2	259	13.8	6.38	12.50	6.12
Show		36347	00 25 04 +47 59 19	RED 14 Ca,Cb	2005	1	233	0.3	16.23	16.40	0.17

Quintuple system
5 visible stars in this system

Precise pa	272.7		Precise sep	0.325		Constellation	Hydra		SAO	36347
HIP	1987		Tycho2	3252-00597-1		Gaia DR2	392562179817077120		HD	2057
BD	BD+47 88		Distance	43.82		Distance ly	142.94		last precise pa	272.7
last precise sep	0.325

Period (P)	28.05y	± 0.46	Periastron (T)	1999.29y	± 0.55	Semi-major axis (a)	0.23a	± 0.008
Eccentricity (e)	0.481	± 0.058	Inclination (i)	164°	± 3.8	Longitude of periastron (ω)	358.9°	± 15.7
Node (Ω)	96.1°	± 16.2	Note			Grade	3	(1=Definitive, 9=Indet.)
Equinox	2000		Last observation	2007

label rho theta 2000 0.123 69.3 2001 0.140 35.7 2002 0.165 10.9 2003 0.192 352.9 2004 0.219 339.3 2005 0.244 328.6 2006 0.266 319.8 2007 0.285 312.3 2008 0.301 305.6 2009 0.315 299.6 2010 0.325 294.0 2011 0.333 288.7 2012 0.338 283.7 2013 0.340 278.7 2014 0.340 273.8 2015 0.337 268.8 2016 0.331 263.7 2017 0.322 258.3 2018 0.310 252.6 2019 0.296 246.4 2020 0.279 239.4 2021 0.258 231.5 2022 0.235 222.1 2023 0.210 210.5 2024 0.182 195.6 2025 0.155 175.3 2026 0.133 147.3 2027 0.120 110.7 2028 0.123 71.2 2029 0.139 37.2 2030 0.164 12.0		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
00251+4803	HDS 56	AB	2012	16	279	0.3	7.72	10.63	F8	NO	002508.50+480250.9
00251+4803	HDS 56	AB	2013	17	273	0.3	7.72	10.63	F8	NO	002508.74+480251.0

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