Andromeda Constellation

Andromeda Constellation Map

Mythology

This large constellation of northern sky represents daughter of Queen Cassiopeia and King Cepheus. In Greek mythology, Andromeda was chained to rock as a sacrifice to the sea monster Cetus, but was saved from certain death by intervention of hero Perseus.

Key Data

Main Stars

 

[ α ] Alpheratz – Alpha Andromedae

Blue-white star also known as Sirrah, its two alternating names comes from Arabic meaning ‘horse’s navel’, because once it was considered to be part of Pegasus a neighbouring constellation. Now it’s marked as head of Andromeda.

 

  • Star system: Spectroscopic binary star system, brighter of the two is a mercury-manganese star
  • Apparent magnitude: +2.06
  • Distance: 97 light years
  • Orbital period: 96.7015 ± 0.0044 days

Primary                                                           

  • Absolute magnitude: -0.19 ± 0.30
  • Mass: 3.8 ± 0.2 M
  • Radius: 2.7 ± 0.4 R
  • Luminosity: 240 L
  • Temperature: 13 800 K
  • Age: 60 million years
  • Rotational period: 2.38195 days
  • Rotational velocity (v sin i): 52 km/s
  • Surface gravity(log g): 3.75 cgs (centimetre-gram-second system of units)
  • Metallicity: [M/H] = 2
  • Spectral type: B8IVpMnHg

Secondary

  • Star type: Early-type A star
  • Absolute magnitude: 2.00 ± 0.30
  • Mass: 1.85 ± 0.13 M
  • Radius: 1.65 ± 0.3 R
  • Luminosity:  13 L
  • Temperature: 8 500 K
  • Age: 70 million years
  • Rotational velocity (v sin i): 110 ± 5 km/s
  • Surface gravity(log g): 4.0 cgs (centimetre-gram-second system of units)
  • Metallicity: [M/H] = 0.2
  • Spectral type: A3V

Optical companion [ADS 94 B]

  • ADS (Aitken Double Star Catalogue): ADS 94 B
  • Not related to α in space, just in line
  • Apparent magnitude: 10.8
  • Distance: 1 360 ± 20 light years
  • Spectral type: G5

 

[ β ] Mirach – Beta Andromedae

  • Star type: Semi-regular variable red giant star
  • Apparent magnitude: +2.01 to +2.10
  • Absolute magnitude: -1.76
  • Distance: 197 ± 7 light years
  • Mass: 3 – 4 M
  • Radius: 100 R
  • Luminosity: 1 995 L
  • Temperature: 3 842 K
  • Rotational period:
  • Rotational velocity: 7.2 km/s
  • Surface gravity(log g): 1.52 cgs (centimetre-gram-second system of units)
  • Metallicity: [Fe/H] -0.05
  • Spectral type: M0 III

 

[ γ1 ] Almach – Gamma Andromedae

Johann Tobias discovered in 1778 that γ Andromedae was a double star. Through small telescope of that day stars appeared as bright, gold-yellow star (γ1 Andromedae or γ Andromedae A, also named Almach) and next dimmer indigo-blue star (γ2 Andromedae or γ Andromedae B). Later it was discovered that γ2 Andromedae is a triple star system.

 

 

  • Star system: quadruple star system
  • Distance: 350 ± 30 light years

 

γ Andromedae A

  • Apparent magnitude: 2.1
  • Absolute magnitude: -3.05
  • Radius: 80 R
  • Luminosity: 2 000 L
  • Temperature: 4 500 K
  • Rotation velocity: < 17 km/s
  • Radial velocity: -11.7 ± 0.9 km/s
  • Spectral type: K3IIb

 

γ Andromedae BC

Wilhelm Struve found that γ2 Andromedae was itself a double star in October 1842 whose component was separated less than an arcseconds.

 

  • Star system: multiple star system
  • Apparent magnitude: 4.84 (BC – combined)
    • Apparent magnitude: 5.5 (B)
    • Apparent magnitude: 6.3 (C)
  • Absolute magnitude: -0.3 (BC combined)
  • Angular separation: 9.6 arcseconds from γ1
  • Orbital Period: 63.67 ± 0 years
  • Radial velocity: -14 ± 5 km/s
  • Spectral type: B5.9V / B9.5V

 

γ Andromedae B

Star system: double star

 

[ δ ] Delta Andromedae A

  • Star type: Orange giant
  • Apparent magnitude: 3.28
  • Absolute magnitude: -0.8
  • Distance: 105 ± 0.5 light years
  • Mass: ~1.3 M
  • Radius: 13.6 ± 0.3 R
  • Luminosity: 68 ± 4 L
  • Temperature: 4 315 K
  • Age: 3.2 billion years
  • Rotational velocity (v sin i): 6.5 km/s
  • Surface gravity(log g): 2.0 ± 0.3 cgs (centimetre-gram-second system of units)
  • Metallicity: [Fe/H] 0.04
  • Spectral type: K3 III

 

[ δ ] Delta Andromedae B

  • Star type: K-type red dwarf
  • Star system: optical binary
  • Spectral type: M3
  • Separation: ~ 900 AU

 

[ ο ] Omicron Andromedae

This star system is defined by peculiar velocity of 34.5 ± 5.9 m/s. In 1949 Omicrons components A and B were resolved, orbital period was derived from measurements made in 1949 (0.1″), 1975 (0.375″) and 2014 (0.21″) giving 117 years. In 1975 component A by speckle interferometry was distinguished to have its own companion (the pair, Aa and Ab) with 5.6 years orbital period. Fourth companion was confirmed in 1988. It was unclear to which star this companion belonged, clear 33.01 day period didn’t helped at first, but later on it was settled that it belonged to companion B (Ba and Bb).

 

  • System type: Blue-white B-type giant (quad-star system)
  • Apparent magnitude: +3.62
  • Absolute magnitude: -2.6
  • Distance: 692 light years
  • Mass:
    • Omicron Andromedae Aa: 3.6  2.9 M
    • Omicron Andromedae Ab: 2.4 M
    • Omicron Andromedae B: 3.6 M
  • Age: 50.1 ± 6.8 million years
  • Orbital period:
    • Omicron Andromedae AB: 117.4 years
    • Omicron Andromedae Aa & Ab: 5.6 years
    • Omicron Andromedae Ba & Bb: 33.01 days
  • Spectral type: B6IIIpe + A2p

 

[ ο ] Omicron Andromedae Aa

  • Mass: 3.6 ± 2.9 M
  • Radius: 6.6 R
  • Luminosity: 1 380 L
  • Temperature: 13 800 K
  • Rotational velocity: 240 km/s

 

[ π ] Pi Andromedae

  • Star type: Blue-white B-type main sequence dwarfs (spectroscopic binary)
  • Apparent magnitude: +4.3
  • Absolute magnitude: -1.97
  • Distance: 600 ± 30 light years
  • Luminosity: 1 136 L
  • Temperature: 158 276 K
  • Orbital period: 143.6 days
  • Rotational velocity: 25 km/s
  • Radial velocity: +8.7 km/s
  • Surface gravity(log g)4.10 cgs (centimetre-gram-second system of units)
  • Metallicity: [Fe/H] +0.20
  • Spectral type: B5 V

 

[ υ ] Upsilon Andromedae

Upsilon Andromedae is a binary system, consisting of an F-type main-sequence star (υ Andromedae A, also named Titawin) and smaller red dwarf. As of 2010 four exo-planets are discovered around binary system. First three are named Saffar, Samh and Majriti (Upsilon Andromedae b, c, d, e). 1st system to host planets around multiple stars. 1st main sequence star to host planets.

 

  • Star type: F-type main sequence star and red dwarf (binary star)
  • Apparent magnitude: 4.1
  • Absolute magnitude: 3.44 ± 0.02
  • Planets: 4 planets
  • Distance: 43.95 ± 0.05 light years

 

[ υ ] Upsilon Andromedae A

  • Star type: Yellow-white dwarf
  • Mass: 1.27 ± 00.6 M
  • Radius: 1.480 ± 0.087 R
  • Luminosity: 3.57 L
  • Temperature: 6 213 ± 44 K
  • Age: 3.12 ± 0.2 billion years
  • Rotational period: 7.3 ± 0.04 days
  • Rotational velocity: 9.5 ± 0.8 km/s
  • Surface gravity(log g): 4.0 ± 0.1 cgs (centimetre-gram-second system of units)
  • Metallicity: [Fe/H] 0.09 ± 0.06
  • Spectral type: F8V

 

[ υ ] Upsilon Andromedae B

  • Star type: Red dwarf
  • Orbital distance (from primary star): 750 AU
  • Spectral type: M4.5V

 

[ υ ] Upsilon Andromedae A Planets

  • Upsilon Andromedae b (Saffar)
    • Mass: 1.7 ± 0.285 MJ
    • Radius: ~1.3 RJ
    • Orbital radius (semimajor axis): 0.0594 ± 0.0003 AU
    • Orbital period: 4.62 ± 0.23 days
    • Eccentricity: 0.022 ± 0.007
    • Inclination: 24 ± 4°
    • Discovery: January 1997 by Geoffrey Marcy & R. Paul Butler
  • Upsilon Andromedae c (Samh)
    • Mass: 13.98 ± 3.8 MJ
    • Orbital radius (semimajor axis): 0.829 ± 0.043 AU
    • Orbital period: 241.26 ± 0.64 days
    • Eccentricity: 0.260 ± 0.079
    • Inclination: 7.9 ± 1°
  • Upsilon Andromedae d (Majriti)
    • Mass: 10.25 ± 2.0 MJ
    • Orbital radius (semimajor axis): 2.530 ± 0.014 AU
    • Orbital period: 1 276.46 ± 0.57 days
    • Eccentricity: 0.299 ± 0.072
    • Inclination: 23.8 ± 1°
  • Upsilon Andromedae e
    • Mass: > 1.059 MJ
    • Orbital radius (semimajor axis): ~5.25 AU
    • Orbital period: 3 848.86 ± 0.74 days
    • Eccentricity: 0.0055 ± 0.0004

 

56 Andromedae

  • Star type: Ageing giant star (probable binary)
  • Apparent magnitude: 5.69
  • Absolute magnitude: +0.76
  • Distance: 330 ± 4 light years
  • Mass: 1.34 ± 0.37 M
  • Radius: 11 R
  • Luminosity: 56.2 L
  • Temperature: 4 765 ± 35 K
  • Age: 3.16 ± 0.965 billion years
  • Radial velocity: +61.77 ± 0.13 km/s
  • Surface gravity(log g): 2.58 ± 0.18 cgs (centimetre-gram-second system of units)
  • Metallicity: [Fe/H] -0.15 ± 0.07
  • Spectral type: K0 III

 

Deep-sky Objects

 

[  1 ] Andromeda[+3.44 +8.92]
M31 - Andromeda GalaxyApparent Magnitude: 3.44
Constellation: Andromeda
Distance: 2.49 million ly
Type: Spiral Galaxy
Other Designations: NGC 224
M32Apparent Magnitude: 8.08
Constellation: Andromeda
Distance: 2.49 million ly
Type: Dwarf early-type Galaxy
Other Designations: NGC 221,
Satellite galaxy to Andromeda galaxy
M110Apparent Magnitude: 8.92
Constellation: Andromeda
Distance: 2.69 million ly
Type: Dwarf Elliptical Galaxy
Other Designations: NGC 205,
Satellite galaxy to Andromeda galaxy

[ 1 ] Andromeda[ +5.7 +11.2 ]
NGC 752 - Open CusterApparent Magnitude: 5.7
Constellation: Andromeda
Distance: 1 300 ly
Type: Open Cluster
Other Designations: Caldwell 28
NGC 891 - Spiral GalaxyApparent Magnitude: 10.8
Constellation: Andromeda
Distance: 27.3 ± 1.8 million ly
Type: Unbarred Spiral Galaxy
Other Designations: Caldwell 23
NGC 7662 - Blue Snowball NebulaApparent Magnitude: 8.6
Constellation: Andromeda
Distance: ~ 2 000 - 6 000 ly
Type: Planetary Nebula
Other Designations: Caldwell 22
NGC 404 - Field GalaxyApparent Magnitude: 11.2
Constellation: Andromeda
Distance: 10.0 ± 0.7 million ly
Type: Field Galaxy
Other Designations: UGC 718

 


Reference list:

Wikipedia.org

Universe: the Definitive Visual Guide by Martin Rees

The STARS: the Definite Visual Guide to the Cosmos Foreword by Maggie Aderin-Pocock

Collins gem Stars by Ian Ridpath

 

Images from:
nasa.gov
wikipedia.org