Your guide to the Solar System and the night sky
Please donate now to help keep TheSkyLive ads-free. This site cannot run without your voluntary donations.
🌎  Greenwich, United Kingdom [change]

Alpheratz - α Andromedae (alpha Andromedae)

Alpheratz, also designated as α Andromedae (alpha Andromedae), is a variable and double sub-giant star in the constellation of Andromeda.

Alpheratz visual magnitude is 2.06, making it the 54th brightest star in the sky. Thanks to its high brightness, Alpheratz is clearly visible when observed from locations with dark skyes, and should be also quite easily visible from light polluted areas.

The table below summarizes the key facts about Alpheratz:

2.06
Sub-giant
Alpheratz - α Andromedae (alpha Andromedae) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 0°.

Celestial coordinates and finder chart of Alpheratz

Alpheratz is situated north of the celestial equator, as such, it is more easily visible from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of Alpheratz are provided in the following table:

00h 08m 23s
+29° 05’ 26”
111.73°
-32.84°
Andromeda

The simplified sky map below shows the position of Alpheratz in the sky:

Finder chart Alpheratz - α Andromedae (alpha Andromedae) star
Simplified finder chart for Alpheratz - α Andromedae (alpha Andromedae).

Visibility of Alpheratz from your location

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Today's Alpheratz - α Andromedae (alpha Andromedae) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 60.9°
Max altitude: 67.6°
Azimuth: 299.1°
Alpheratz - α Andromedae (alpha Andromedae) is above the horizon from Greenwich, United Kingdom

Digitized Sky Survey image of Alpheratz

The image below is a photograph of Alpheratz from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of Alpheratz is 0.136 arcsec per year in Right Ascension and -0.163 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

Image of Alpheratz - α Andromedae (alpha Andromedae) star
DSS2 image of Alpheratz. The red arrow shows the motion of Alpheratz during the next 1000 years (2.27 arcmin in Right Ascension and -2.72 arcmin in declination);

Distance of Alpheratz from the Sun and relative movement

Alpheratz is distant 97.02 light years from the Sun and it is moving towards the Sun at the speed of 12 kilometers per second.

29.76 pc
97.02 ly
-12 km/s
0.136 arcsec/year
-0.163 arcsec/year

Spectral properties of Alpheratz

Alpheratz belongs to spectral class B8 and has a luminosity class of IV corresponding to a sub-giant star. Alpheratz is also a MnHg chemically peculiar star.

-0.31
B8IV
11744K

The red dot in the diagram below shows where Alpheratz is situated in the Hertzsprung–Russell diagram.

HR Diagram
H-R diagram showing the position of Alpheratz. Attribution: Richard Powell / CC BY-SA

Alpheratz star system properties

Alpheratz is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the Alpheratz double sysyem:

2.06
10.56
8.5
81.5 arcsec

Alternative designations of Alpheratz

Alpheratz
α Andromedae
(alpha Andromedae)
21 Andromedae
SAO73765
SAO73765