Andromeda

Andromeda (abbreviation And) is a large, prominent northern constellation, to the south of Cassiopeia, between Perseus and Pegasus.

In mythology, Andromeda was chained to a rock to be sacrificed to Cetus (the Whale) as a punishment to her mother, Cassiopeia, who had boasted that she was more beautiful than the daughters of Neptune.

Andromeda's three brightest stars lie along an arc that stretches to the northeast of the Square of Pegasus, of which Alpheratz (Alpha Andromedae) forms a corner. Alpheratz and Mirach, the two brightest stars, have identical magnitudes, which is a coincidence found in no other constellation. Near to third-ranked Almaak is the most outstanding feature of Andromeda – our nearest neighboring major galaxy, the Andromeda Galaxy.

See below for details of the constellation's brightest stars and interesting deep sky objects.

S Andromedae

S Andromedae, also known as SN 1885 (Supernova 1885), is the only supernova seen to date in the Andromeda Galaxy and the first supernova observed beyond the galaxy in which we live, Milky Way Galaxy. S Andromedae (a variable star designation) was discovered on 19 August 1885, by the Irish amateur astronomer Isaac Ward in Belfast, and independently the following day by Ernst Hartwig (1851–1923) at Dorpat Observatory in Estonia; Hartwig was the first to realize its significance.

S Andromedae reached magnitude 6 between 17 and 20 August and had faded to magnitude 16 by February 1890. In 1988, R. A. Fesen and colleagues using the 4-m Mayall telescope at Kitt Peak discovered the remnant of the explosion; further observations were made with the Hubble Space Telescope in 1995.

Andromedids

The Andromedids is a meteor shower associated with Comet 3D/Biela, not observed since 1940. The first recorded appearance of the shower, which radiated from near the star Gamma Andromedae, was in 1741. Spectacular meteor storms were observed in November 1872 and 1885, following the break-up of the associated comet, when the rates were many thousands per hour. The shower is also known as the Bielids.

Stars in Andromeda brighter than magnitude 4.0
star	vis mag	abs mag	spec type	distance (ly)	RA (h m s)	Dec (° ' ")
Alpha (Alpheratz)	2.07	-0.30	B8IVpMnHg	97	00 08 23	+29 05 26
Beta (Mirach)	2.07	-1.87	M0IIa	199	01 09 44	+35 37 14
Gamma (Almaak)	2.10	-3.09	K3IIb+A0V	355	02 03 54	+42 19 47
Delta	3.27	0.81	K3III	101	00 39 20	+30 51 40
51	3.59	-0.05	K3III	174	01 38 00	+48 37 42
Omicron	3.6v	1.33	B6IIIpe+A2p	141	23 01 55	+42 19 34
Lambda	3.82v	1.75	G8III-Iv	84	23 37 34	+46 27 30
Mu	3.86	0.75	A5V	136	00 56 45	+38 29 58
Upsilon	4.63	3.96	F8V	43.9	01 36 48	+41 24 20
Gliese 67	4.96	4.45	G2V	41.4	01 41 47	+42 36 48
Groombridge 34 (A)	8.09	10.33	M1.5V	11.62	00 18 23	+44 01 22
Ross 248	12.29	14.79	M5.5V	10.32	23 41 55	+44 10 30

Other objects of interest
name	type of object	notes
R And	star	Mira variable. Mag. range 5.8 to 14.9; mean period 409 days; RA 02h 24.0m, Dec +38° 35'
Z And	star	The prototype Z Andromedae star
LL And	star	See brown dwarf.
Andromeda Galaxy	galaxy	M31 (NGC 224). See main entry
M32 (NGC 221)	galaxy	Bright satellite of the Andromeda Galaxy.
M110 (NGC 205)	galaxy	Bright satellite of the Andromeda Galaxy.
Cassiopeia Dwarf	galaxy	Faint satellite of the Andromeda Galaxy.
Pegasus Dwarf	galaxy	Faint satellite of the Andromeda Galaxy.
NGC 404	galaxy	Mirach's Ghost. Lies very close to Mirach in our line of sight.
NGC 891	galaxy	One of best examples of an edge-on spiral. RA 02h 19m, Dec +42° 7'
NGC 752	open cluster	Fine object, 5° S. of Almaak, best viewed with binoculars as its 70-80 stars are widely scattered. RA 01h 57.8m, Dec +37° 41'
Blue Snowball Nebula (NGC 7662)	planetary nebula	See main entry