Barred spiral galaxy swirls in the night sky

This image shows the swirling shape of galaxy NGC 2217, in the constellation of Canis Major (The Great Dog). In the central region of the galaxy is a distinctive bar of stars within an oval ring. Further out, a set of tightly wound spiral arms almost form a circular ring around the galaxy. NGC 2217 is therefore classified as a barred spiral galaxy, and its circular appearance indicates that we see it nearly face-on.

The outer spiral arms have a bluish colour, indicating the presence of hot, luminous, young stars, born out of clouds of interstellar gas. The central bulge and bar are yellower in appearance, due to the presence of older stars. Dark streaks can also be seen in places against the galaxy’s arms and central bulge, where lanes of cosmic dust block out some of the starlight.

The majority of spiral galaxies in the local Universe — including our own Milky Way — are thought to have a bar of some kind, and these structures play an important role in the development of a galaxy. They can, for example, funnel gas towards the centre of the galaxy, helping to feed a central black hole, or to form new stars.

Crédit:

ESO

À propos de l'image

Identification:potw1204a
Type:Observation
Date de publication:23 janvier 2012 10:00
Taille:1688 x 1841 px

À propos de l'objet

Nom:NGC 2217
Type:Local Universe : Galaxy : Type : Barred
Distance:65 million années lumière
Constellation:Canis Major
Catégorie:Galaxies

Image Formats

Grand JPEG
1,1 Mio
JPEG taille écran
252,8 Kio

Zoomable


Fonds d'écran

1024x768
206,2 Kio
1280x1024
405,4 Kio
1600x1200
724,0 Kio
1920x1200
691,6 Kio
2048x1536
944,2 Kio

Coordinates

Position (RA):6 21 40.35
Position (Dec):-27° 13' 56.90"
Field of view:4.44 x 4.84 arcminutes
Orientation:North is 0.2° left of vertical

Couleurs & filtres

DomaineLongueur d'ondeTélescope
Visible
B
440 nmESO 3.6-metre telescope
EFOSC
Visible
V
547 nmESO 3.6-metre telescope
EFOSC
Visible
R
643 nmESO 3.6-metre telescope
EFOSC

 

Voir aussi notre