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.

Créditos:

ESO

Sobre a imagem

Id:potw1204a
Tipo:Observação
Data de divulgação:23 de Janeiro de 2012 às 10:00
Tamanho:1688 x 1841 px

Sobre o objeto

Nome:NGC 2217
Tipo:Local Universe : Galaxy : Type : Barred
Distância:65 milhão anos-luz
Constellation:Canis Major
Categoria:Galaxies

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Coordenadas

Position (RA):6 21 40.35
Position (Dec):-27° 13' 56.90"
Field of view:4.44 x 4.84 arcminutes
Orientação:O norte está a 0.2° à esquerda da vertical

Cores e filtros

BandaComprimento de ondaTelescópio
Óptico
B
440 nmESO 3.6-metre telescope
EFOSC
Óptico
V
547 nmESO 3.6-metre telescope
EFOSC
Óptico
R
643 nmESO 3.6-metre telescope
EFOSC