HEIC: Stars Fleeing a Cosmic Crash (ESO 489-56)

[bystander]

Stars Fleeing a Cosmic Crash
ESA/HEIC Hubble Picture of the Week | 2013 Aug 12

---

Astronomical pictures sometimes deceive us with tricks of perspective. Right in the centre of this image, two spiral galaxies appear to be suffering a spectacular collision, with a host of stars appearing to flee the scene of the crash in a chaotic stampede.

However, this is just a trick of perspective. It is true that two spiral galaxies are colliding, but they are millions of light-years away, far beyond the cloud of blue and red stars near the merging spiral. This sprinkling of stars is actually an isolated, irregular dwarf galaxy named ESO 489-056. The dwarf galaxy is actually much more distant than many bright stars in the foreground of the image, which are located much closer to us, in the Milky Way.

ESO 489-056 is located 16 million light-years from Earth in the constellation of Canis Major (The Greater Dog), in our local Universe. It is composed of a few billion red and blue stars — a very small number when compared to galaxies like the Milky Way, which is estimated to contain around 200 to 400 billion stars, or the Andromeda Galaxy, which contains a mind-boggling one trillion.

A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Luca Limatola.

Credit: ESA/Hubble & NASA
Acknowledgement: Luca Limatola

<< Previous ESA/HEIC Hubble POTW

[Ann]

That is so fascinating! What an incredible perspective!

The background pair of galaxies resembles the colliding pair (or triplet?) of galaxies, NGC 6050, in the Hercules cluster of galaxies.

http://www.spacetelescope.org/images/potw1332a/ wrote:

ESO 489-056 is located 16 million light-years from Earth in the constellation of Canis Major (The Greater Dog), in our local Universe. It is composed of a few billion red and blue stars

This description makes it sound as if the foreground galaxy, ESO 489-056, is a neutral-colored galaxy, equally dominated by red and blue stars. That, however, is not the case. It is quite clear from the clumpy appearance of ESO 489-056 that it contains a lot of star formation. There are clearly many more bright blue than bright red stars in this galaxy.

Also, according to the SIMBAD link provided by this article, the color of ESO 489-056 is quite blue. Its B magnitude is only 0.41 magnitudes fainter than its R magnitude.

In any case, this is a most fascinating picture.

Ann