Images of Andromeda taken with NASA's Spitzer and Chandra Space Telescopes at the Gemini North Observatory in Hawaii are giving scientists a whole new view of the Milky Way's closest neighbor. The latest pictures reveal details about Andromeda's central bulge and inner disk as well as its very heart. 

Researchers put together more than 3,000 separate infrared images taken with Spitzer to create a series of mosaic images that separated Andromeda's old stars (which resembled smooth, soft blue smudge) from the thick veil of dust and gas (which appered as concentric rings of fire) covering it. Based on the mosaic, researchers estimated the total amount of infrared light emitted by Andromeda is equal to 4 billion suns.

Since the amount of light a star gives off depends on its mass, researchers calculated the total mass of all the stars in Andromeda is equal to about 110 billion suns. That's not counting the small red dwarfs that are less massive than the sun. Adding them to the equation would boost the number to about a trillion stars.

The new data also allowed the team to estimate the number of new stars born in Andromeda each year. The star population growth over there was pegged at about 0.6 solar masses per year on average - an unxpectedly low figure than most scientists anticipated. The more fertile Milky Way is calculated to produce about half a dozen baby stars every year.

Meanwhile, the Chandra Space Telescope team, led by Knut Olsen, presented the deepest and highest resolution images taken of Andromeda's central bulge and inner disk. The images show thousands of individual stars within 6,500 light-years of the galaxy’s nucleus.

According to the team's researches, most of those stars are relatively old and have heavy-element compositions similar to our Sun. This means Andromeda’s inner disk could be at least 6 billion years old (the universe itself is thought to have celebrated more than 13 billion birthdays).

New images taken by Chandra X-ray telescope revealed a collection of point-like sources within a diffuse, X-ray emitting cloud of hot gas. What heats the gas, scientists say, could be the shockwaves produced during supernova explosions. As matter falls towards the neutron star or black hole, it is heated by friction to tens of millions of degrees until it emits X-rays.