00491+5749 STF 60 AB (Achird)

Coord 2000	00491+5749		Discov num	STF  60		Comp	AB		Coord arcsec 2000	00 49 06.29 +57 48 54.7
Date first	1779		Date last	2023		Obs	1087
Pa first	62		Pa last	327.6		P.A. Now (θ)	328.9° (calc)
Sep first	11.3		Sep last	13.54		Sep. Now (ρ)	13.558" (calc)
Mag pri	3.52		Mag sec	7.36		delta mag (ΔM)	3.84		Spectral class	G1V+M (yellow/red)
Pri motion ra	+114		Sec motion ra	+115
Pri motion dec	-057		Sec motion dec	-047
Notes	N O P (See Notes, Orbital solution, 100-year proper motion)

rPM=0.079 (< 0.3, Physical double) This double is physical.

Show	name	SAO	coord	wds_name	last	obs	pa	sep	mag1	mag2	d_mag	orb	current
Show		21732	00 49 06 +57 48 55	STF 60 Aa,Ab	2015	2	134	5.1	3.52
Show	Achird	21732	00 49 06 +57 48 55	STF 60 AB	2023	1087	328	13.5	3.52	7.36	3.84	Y	<===
Show		21732	00 49 06 +57 48 55	STF 60 AC	2000	4	260	225.0	3.52	11.40	7.88
Show		21732	00 49 06 +57 48 55	STF 60 AD	2011	7	354	189.4	3.52	12.80	9.28
Show		21732	00 49 06 +57 48 55	STF 60 AE	2023	25	126	66.0	3.52	10.15	6.63
Show		21732	00 49 06 +57 48 55	STF 60 AF	2000	3	276	378.3	3.52	11.53	8.01
Show		21732	00 49 06 +57 48 55	STF 60 AG	2012	19	259	419.7	3.52	9.53	6.01
Show		21732	00 49 06 +57 48 55	STF 60 AH	2012	4	355	701.1	3.52	8.41	4.89
Show		21732	00 49 06 +57 48 55	SMR 2 AI	2012	7	73	90.3	3.52	11.60	8.08
Show		21732	00 49 06 +57 48 55	SMR 2 AJ	2012	5	262	237.1	3.52	12.30	8.78
Show		21732	00 49 05 +57 49 04	STF 60 BC	2016	5	259	235.4	7.36	11.40	4.04
Show		21732	00 49 05 +57 49 04	STF 60 BD	2000	1	1	172.2	7.36	12.80	5.44
Show		21732	00 49 05 +57 49 04	STF 60 BE	2020	4	126	105.5	7.36	10.15	2.79
Show		21732	00 49 05 +57 49 04	STF 60 BF	2016	3	275	388.1	7.36	11.53	4.17
Show		21730	00 49 05 +57 49 04	STF 60 BG	2016	3	256	420.0	7.36	9.53	2.17
Show		21732	00 49 05 +57 49 04	STF 60 BH	2020	5	355	688.4	7.36	8.41	1.05
Show		21730	00 48 19 +57 49 34	STF 60 FG	2015	10	188	142.2	11.53	9.53	2.00

11-fold system
11 estimated visually detectable stars in this system

Common name	Achird		Constellation	Cassiopeia		SAO	21732		HIP	3821
Tycho2	3663-02669-1		HD	4614		HR	219		GC	962
ADS	671		BD	BD+57 150		Bayer	Eta Cassiopeiae		Bayer name	Eta Cas
Flamsteed	24 Cassiopeiae		Flamsteed name	24 Cas		Distance	5.95		Distance ly	19.41
Bayer greek	η Cas

Other names

MARFAK

Meaning

first applied to ? Cassiopeiae in the Skalnate Pleso Atlas of the Heavens published in 1950, but is not known prior to that.

Period (P)	479.27y		Periastron (T)	1889.93y		Semi-major axis (a)	12.04a
Eccentricity (e)	0.497		Inclination (i)	35.6°		Longitude of periastron (ω)	269.8°
Node (Ω)	278°		Notes	n		Reference	Sca2015c
Equinox	2000		Last observation	2014		Grade	3	(1=Definitive, 9=Indet.)

label theta rho 2000 317.4 12.783 2001 317.8 12.819 2002 318.3 12.854 2003 318.8 12.888 2004 319.2 12.922 2005 319.7 12.956 2006 320.1 12.989 2007 320.6 13.022 2008 321.1 13.054 2009 321.5 13.085 2010 321.9 13.117 2011 322.4 13.147 2012 322.8 13.178 2013 323.3 13.208 2014 323.7 13.237 2015 324.2 13.266 2016 324.6 13.295 2017 325.0 13.323 2018 325.5 13.350 2019 325.9 13.378 2020 326.3 13.405 2021 326.7 13.431 2022 327.2 13.457 2023 327.6 13.483 2024 328.0 13.509 2025 328.4 13.534 2026 328.9 13.558 2027 329.3 13.582 2028 329.7 13.606 2029 330.1 13.630 2030 330.5 13.653 2031 330.9 13.676 2032 331.3 13.698 2033 331.7 13.720 2034 332.1 13.742 2035 332.6 13.764 2036 333.0 13.785 2037 333.4 13.805 2038 333.8 13.826 2039 334.2 13.846 2040 334.6 13.866 2041 335.0 13.885 2042 335.4 13.905 2043 335.8 13.924 2044 336.2 13.942 2045 336.6 13.960 2046 336.9 13.978 2047 337.3 13.996 2048 337.7 14.014 2049 338.1 14.031 2050 338.5 14.048

Note: Theta is PA, Rho is Sep. For yearly orbits, data refer to Jan 1st. Measures: green=micrometric, blue=interferometric, purple=photographic