Andromeda in a new light

Andromeda in a new light
The Andromeda Galaxy is our nearest large galactic neighbour, containing several hundred billion stars. Combined, these images show all stages of the stellar life cycle. The infrared image from Herschel shows areas of cool dust that trace reservoirs of gas in which forming stars are embedded. The optical image shows adult stars. XMM-Newton’s X-ray image shows the violent endpoints of stellar evolution, in which individual stars explode or pairs of stars pull each other to pieces. Credits: infrared: ESA/Herschel/PACS/SPIRE/J. Fritz, U. Gent; X-ray: ESA/XMM-Newton/EPIC/W. Pietsch, MPE; optical: R. Gendler

Two ESA observatories have combined forces to show the Andromeda Galaxy in a new light. Herschel sees rings of star formation in this, the most detailed image of the Andromeda Galaxy ever taken at infrared wavelengths, and XMM-Newton shows dying stars shining X-rays into space.

During Christmas 2010, ESA’s Herschel and XMM-Newton space observatories targeted the nearest large spiral galaxy M31. This is a galaxy similar to our own Milky Way – both contain several hundred billion stars. This is the most detailed far-infrared image of the ever taken and shows clearly that more stars are on their way.

Sensitive to far-infrared light, Herschel sees clouds of cool dust and gas where stars can form. Inside these clouds are many dusty cocoons containing forming stars, each star pulling itself together in a slow gravitational process that can last for hundreds of millions of years. Once a star reaches a high enough density, it will begin to shine at optical wavelengths. It will emerge from its birth cloud and become visible to ordinary telescopes.

Many are spiral in shape but Andromeda is interesting because it shows a large ring of dust about 75 000 light-years across encircling the centre of the galaxy. Some astronomers speculate that this dust ring may have been formed in a recent collision with another galaxy. This new Herschel image reveals yet more intricate details, with at least five concentric rings of star-forming dust visible.

Superimposed on the infrared image is an X-ray view taken almost simultaneously by ESA’s XMM-Newton observatory. Whereas the infrared shows the beginnings of , X-rays usually show the endpoints of stellar evolution.

XMM-Newton highlights hundreds of X-ray sources within Andromeda, many of them clustered around the centre, where the stars are naturally found to be more crowded together. Some of these are shockwaves and debris rolling through space from exploded stars, others are pairs of stars locked in a gravitational fight to the death.

In these deadly embraces, one star has already died and is pulling gas from its still-living companion. As the gas falls through space, it heats up and gives off X-rays. The living star will eventually be greatly depleted, having much of its mass torn from it by the stronger gravity of its denser partner. As the stellar corpse wraps itself in this stolen gas, it could explode.

Both the infrared and X-ray images show information that is impossible to collect from the ground because these wavelengths are absorbed by Earth’s atmosphere. The twinkling starlight seen from Earth is indeed a beautiful sight but in reality contains less than half the story. Visible light shows us the adult stars, whereas infrared gives us the youngsters and X-rays show those in their death throes.

To chart the lives of , we need to see it all and that is where and contribute so much.


Explore further

Akari's observations of galaxy M101

Citation: Andromeda in a new light (2011, January 5) retrieved 19 September 2019 from https://phys.org/news/2011-01-andromeda.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
0 shares

Feedback to editors

User comments

Jan 05, 2011
Five concentric rings? Stars moving radially outward from Milky Way center? Fermi bubbles here and in M82? Still think the galactic core is not ejecting new matter, seeding galaxies from within? Think again. Sorry the explanation is not convenient. Nature need not accommodate our 'accepted' science theories.

Jan 05, 2011
Nature need not accommodate our 'accepted' science theories.

Right. When observations contradict theories we develop new theories that match the observations and predict new things we can test.

If you think galaxies are seeding themselves demonstrate by finding something your theory predicts that is contradictory to the "accepted" theory. Until then just keep cranking away.

Jan 07, 2011
It is not my theory. In 1985, LaViolette predicted the now observed Pioneer Anomoly, calculated to within a factor of two of best data. For those paying attention, that alone should signal ”Attention“.

Jan 07, 2011
Is there really enough clouds of gas and dust to create the quantity of Suns in existence?

Is this a trick question? Am I missing something? Are there really 52 cards in this deck of 52 cards?

I guess if the question is, "Do we see enough matter floating around that isn't stars to support the idea that some of it has gathered into stars?" then the answer is I don't know.

But I'm sure that nobody has provided enough evidence to convince the scientific field that the core of the sun is neutronium, or infused with dark matter, or is spewing out newly created matter.

Wait for Turyshev and Toth on the Pioneer Anomaly. They think they solved that one without the sun self seeding.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more