ESA title
Science & Exploration

Andromeda’s coat of many colours

27/04/2011 6955 views 19 likes
ESA / Science & Exploration / Space Science / Herschel

ESA’s fleet of space telescopes has captured the nearby Andromeda Galaxy, also known as M31, in different wavelengths. Most of these wavelengths are invisible to the eye and each shows a different aspect of the galaxy’s nature.

Visible light, as seen by optical ground-based telescopes and our eyes, reveals the various stars that shine in the Andromeda Galaxy, yet it is just one small part of the full spectrum of electromagnetic radiation. There are many different wavelengths that are invisible to us but which are revealed by ESA’s orbiting telescopes.

Starting at the long wavelength end, the Planck spacecraft collects microwaves. These show up particles of incredibly cold dust, at just a few tens of degrees above absolute zero. Slightly higher temperature dust is revealed by the shorter, infrared wavelengths observed by the Herschel space telescope. This dust traces locations in the spiral arms of the Andromeda Galaxy where new stars are being born today.

The XMM-Newton telescope detects wavelengths shorter than visible light, collecting ultraviolet and X-rays. These show older stars, many nearing the end of their lives and others that have already exploded, sending shockwaves rolling through space. By monitoring the core of Andromeda since 2002, XMM-Newton has revealed many variable stars, some of which have undergone large stellar detonations known as novae.

Ultraviolet wavelengths also display the light from extremely massive stars. These are young stars that will not live long. They exhaust their nuclear fuel and explode as supernovae typically within a few tens of millions of years after they are born. The ultraviolet light is usually absorbed by dust and re-emitted as infrared, so the areas where ultraviolet light is seen directly correspond to relatively clear, dust-free parts of Andromeda.

By putting all of these observations together, and seeing Andromeda in its many different colours, astronomers are able to follow the life cycle of the stars.

Related Links

Science & Exploration

XMM-Newton overview

01/01/1970 64626 views
Open item
Andromeda: our nearest large galactic neighbour
Science & Exploration

Andromeda’s once and future stars

05/01/2011 10568 views 18 likes
Read
Giant star IRC+10216
Science & Exploration

Recipe for water: just add starlight

02/09/2010 2696 views 8 likes
Read
The Herschel and Planck AAAF Grand Prix 2010 award ceremony
Science & Exploration

Herschel and Planck win the French Grand Prix

10/06/2010 1661 views 2 likes
Read
NGC 1999: Truly a hole in space.
Science & Exploration

Herschel finds a hole in space

11/05/2010 10555 views 32 likes
Read
The white dwarf and its companion
Science & Exploration

XMM-Newton uncovers a celestial Rosetta stone

03/09/2009 2919 views 1 likes
Read
Artist's impression of galaxy and HLX-1 (blue star to the left)
Science & Exploration

XMM-Newton discovers a new class of black holes

01/07/2009 5865 views 22 likes
Read
Illustration of a magnetar
Science & Exploration

Giant eruption reveals 'dead' star

16/06/2009 3531 views 6 likes
Read
Messier 82
Science & Exploration

XMM-Newton exclusive photo: Messier 82

08/04/2009 3231 views 4 likes
Read
Science & Exploration

Planck’s new view of the cosmic theatre

11/01/2011 8117 views 16 likes
Read
The microwave sky as seen by Planck
Science & Exploration

Planck unveils the Universe – now and then

05/07/2010 21806 views 35 likes
Read
Planck image of a region in the Orion Nebula
Science & Exploration

Planck highlights the complexity of star formation

26/04/2010 4343 views 5 likes
Read