A spiral in Andromeda

Not to be confused with our neighbouring Andromeda Galaxy, the Andromeda constellation is one of the 88 modern constellations. More importantly for this image, it is home to the pictured NGC 7640.

Many different classifications are used to identify galaxies by shape and structure — NGC 7640 is a barred spiral type. These are recognisable by their spiral arms, which fan out not from a circular core, but from an elongated bar cutting through the galaxy’s centre. Our home galaxy, the Milky Way, is also a barred spiral galaxy. NGC 7640 might not look much like a spiral in this image, but this is due to the orientation of the galaxy with respect to Earth — or to Hubble, which acted as photographer in this case! We often do not see galaxies face on, which can make features such as spiral arms less obvious.

There is evidence that NGC 7640 has experienced some kind of interaction in its past. Galaxies contain vast amounts of mass, and therefore affect one another via gravity. Sometimes these interactions can be mild, and sometimes hugely dramatic, with two or more colliding and merging into a new, bigger galaxy. Understanding the history of a galaxy, and what interactions it has experienced, helps astronomers to improve their understanding of how galaxies — and the stars within them — form.

Credit:

ESA/Hubble & NASA

About the Image

Id:potw1706a
Type:Observation
Release date:6 February 2017, 06:00
Size:3988 x 4012 px

About the Object

Name:NGC 7640
Type:Local Universe : Galaxy : Type : Spiral
Distance:30 million light years
Constellation:Andromeda
Category:Galaxies

Image Formats

Large JPEG
9.2 MB
Screensize JPEG
453.5 KB

Zoomable


Wallpapers

1024x768
398.5 KB
1280x1024
718.6 KB
1600x1200
1.1 MB
1920x1200
1.4 MB
2048x1536
1.9 MB

Coordinates

Position (RA):23 22 7.32
Position (Dec):40° 50' 57.87"
Field of view:3.32 x 3.34 arcminutes
Orientation:North is 158.5° left of vertical

Colours & filters

BandWavelengthTelescope
Optical
V
606 nm Hubble Space Telescope
ACS
Optical
I
814 nm Hubble Space Telescope
ACS

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