Interacting Galaxies Group Arp 194
Over the past 19 years Hubble has taken dozens of exotic pictures of galaxies going "bump in the night" as they collide with each other and have a variety of close encounters of the galactic kind. Just when you thought these interactions couldn't look any stranger, this image of a trio of galaxies, called Arp 194, looks like one of the galaxies has sprung a leak. The bright blue streamer is really a stretched spiral arm full of newborn blue stars. This typically happens when two galaxies interact and gravitationally tug at each other.
Resembling a pair of owl eyes, the two nuclei of the colliding galaxies can be seen in the process of merging at the upper left. The blue bridge looks like it connects to a third galaxy. In reality the galaxy is in the background and not connected at all. Hubble's sharp view allows astronomers to try and visually sort out what are foreground and background objects when galaxies, superficially, appear to overlap. This picture was issued to celebrate the 19th anniversary of the launch of the Hubble Space Telescope aboard the space shuttle Discovery in 1990. During the past 19 years Hubble has made more than 880,000 observations and snapped over 570,000 images of 29,000 celestial objects.
The Pistol Star: A Brilliant Star in Milky Way's Core
Astronomers using NASA's Hubble Space Telescope have identified what may be the most luminous star known — a celestial mammoth which releases up to 10 million times the power of the Sun and is big enough to fill the diameter of Earth's orbit. The star unleashes as much energy in six seconds as our Sun does in one year.
The image, taken by a University of California, Los Angeles (UCLA)-led team with the recently installed Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) aboard Hubble, also reveals a bright nebula, created by extremely massive stellar eruptions. The nebula is so big (four light-years) that it would nearly span the distance from the Sun to Alpha Centauri, the nearest star to Earth's solar system.
The astronomers estimate that when the titanic star was formed one to three million years ago, it may have weighed up to 200 times the mass of the Sun before shedding much of its mass in violent eruptions.
"This star may have been more massive than any other star, and now it is without question still among the most massive — even at the low end of our estimates," says Don F. Figer of UCLA. "Its formation and life stages will provide important tests for new theories about star birth and evolution."
Hubble - Spitzer Color Mosaic of the Galactic Center
This composite color infrared image of the center of our Milky Way galaxy reveals a new population of massive stars and new details in complex structures in the hot ionized gas swirling around the central 300 light-years. This sweeping panorama is the sharpest infrared picture ever made of the Galactic core.
Source : HubbleSite
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