Ophiuchus and the Galactic Centre

Basic Information

What is this?

An image towards the centre of our Galaxy

Where is it in the sky?

The centre of the image is in the constellation of Ophiuchus

How big is it?

The image is around 50 degrees across

How far away is it?

Most of the material is hundreds or thousands of light years away

What do the colours represent?

Redder colours show colder material, while whitish tones show warmer dust

This image is directed roughly towards the centre of our Galaxy, and shows cold dust laced between the stars.  The colder material looks redder in this image, which is created by combining Planck data with shorter wavelength data from NASA's IRAS satellite.  The plane of our Galaxy is seen running across the bottom, with the Galactic centre in the lower-right. The "forked" feature on the right is a cloud of gas and dust around the star rho Ophiuchi, and is a region where stars are currently forming.

The same region of sky in visible wavelength.  Hover the cursor over to see the Planck image overlaid.
The same region of sky at visible wavelengths. Hover the mouse over to see the Planck image overlaid. Image credit: DSS (visible); ESA / HFI / LFI (microwave)

The same patch of sky is shown on the right at visible wavelengths, with the Planck image overlaid if you hover your mouse over it.  The galaxy looks dark at visible wavelengths, with the dust absorbing the light from stars close to the centre of our Galaxy.  The dust is re-radiating the light at far-infrared and microwave wavelengths, and is detected by Planck and IRAS.  The bright triangle on the right in the visible image is the head of the constellation of Scorpius, close to the Ophiuchus star cloud.

Because Planck is mapping the entire sky, it can observe the gas and dust over the whole sky.  Other experiments, such as Herschel, can examine the dust at much higher resolution, but only over small regions.  The image at the bottom of the page shows the patch of sky with a Herschel image of a small sub-region.

 

You can also see this part of the sky at different wavelengths on Chromoscope.

Herschel and Planck/IRAS views of dust in our Galaxy
Caption. Image credit: Herschel (left), ESA / HFI / IRAS (right).

Detailed Information

Object Name: 
Ophiuchus
Type of Object: 
Region of Sky
Image Scale: 
50 degrees across
Constellation: 
Ophiuchius the Serpent Bearer
Instrument: 
HFI and IRAS
Date of Release: 
17/03/2010