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The Birth of Stars
The spectacular new camera installed on NASA's Hubble Space Telescope during Servicing Mission 4 in May has
delivered the most detailed view of star birth in the graceful, curving arms of the nearby spiral galaxy M83.
Nicknamed
the Southern Pinwheel, M83 is undergoing more rapid star formation than our own Milky Way galaxy, especially in its nucleus.
The sharp 'eye' of the Wide Field Camera 3 (WFC3) has captured hundreds of young star clusters, ancient swarms of globular
star clusters, and hundreds of thousands of individual stars, mostly blue supergiants and red supergiants.
WFC3's broad
wavelength range, from ultraviolet to near-infrared, reveals stars at different stages of evolution, allowing astronomers
to dissect the galaxy's star-formation history.
The image reveals in unprecedented detail the current rapid rate of
star birth in this famous "grand design" spiral galaxy. The newest generations of stars are forming largely in clusters on
the edges of the dark dust lanes, the backbone of the spiral arms. These fledgling stars, only a few million years old, are
bursting out of their dusty cocoons and producing bubbles of reddish glowing hydrogen gas.
The excavated regions give
a colorful "Swiss cheese" appearance to the spiral arm. Gradually, the young stars' fierce winds (streams of charged particles)
blow away the gas, revealing bright blue star clusters. These stars are about 1 million to 10 million years old. The older
populations of stars are not as blue.
A bar of stars, gas, and dust slicing across the core of the galaxy may be instigating
most of the star birth in the galaxy's core. The bar funnels material to the galaxy's center, where the most active star formation
is taking place. The brightest star clusters reside along an arc near the core.
The remains of about 60 supernova blasts,
the deaths of massive stars, can be seen in the image, five times more than known previously in this region. WFC3 identified
the remnants of exploded stars. By studying these remnants, astronomers can better understand the nature of the progenitor
stars, which are responsible for the creation and dispersal of most of the galaxy's heavy elements.
M83, located in
the Southern Hemisphere, is often compared to M51, dubbed the Whirlpool galaxy, in the Northern Hemisphere. Located 15 million
light-years away in the constellation Hydra, M83 is two times closer to Earth than M51.
Image Credit: NASA, ESA,
R. O'Connell (University of Virginia), B. Whitmore (Space Telescope Science Institute), M. Dopita (Australian National University),
and the Wide Field Camera 3 Science Oversight Committee
StarDate
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November 2009
The bright, beautiful constellations of winter creep into prime viewing time during
the longer, cooler nights of November. Beautiful Orion rises in mid-evening early in the month, but by early evening at month's end. Taurus, the bull, charges into view ahead of Orion, with Gemini, the twins, rising to the north of Orion. The Dog Star Sirius, the brightest star in the night sky, follows the hunter in late evening. Venus, the "morning star," disappears in the dawn glare by month's end, but Mars is growing brighter as we head toward winter.
3 Spica, the brightest star of Virgo, aligns just to the right of Venus,
the brilliant "morning star," low in the eastern sky about 45 minutes before sunrise.
8-9 The Moon and Mars are low in the east shortly after midnight, and high in the south at first light. Mars is to the lower
left of the Moon as they rise on the morning of the 8th, and much closer to its upper left on the 9th.
10 Regulus, the brightest star of Leo, is quite close to the left of the Moon as they rise after midnight. Orange Mars stands above them.
12-13 Saturn, which looks like a bright star, is to the left of the Moon at first light on the 12th, and above the Moon on the
13th. Spica is to their lower right.
17 The Leonid meteor shower peaks this morning. There is no Moon to interfere with the shower.
22-24 The Moon moves past Jupiter, which looks like a brilliant cream-colored star. They are in the south at nightfall. Jupiter is closest to the
Moon on the 23rd, standing just below it. |
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