Orion’s Veil Pulled Back

Written by The Night Sky Guy on February 10, 2010 – 12:10 pm -

New Clos-up of Orion Nebula; Click image to enlarge

New Close-up portrait of Orion Nebula, M42; Click image to enlarge

The Great Orion Nebula, one of the perennial favorite scenic wonders of the night sky has begun to reveal its innermost secrets.  A new dramatic image of this giant gas cloud has been showcased by the European Southern Observatory’s new VISTA survey telescope. The telescope’s huge field of view can show the full splendor of the whole nebula and VISTA’s infrared vision also allows it to peer deeply into dusty regions that are normally hidden and expose the curious behavior of the very active young stars buried there.

The Orion Nebula is a vast stellar nursery lying about 1,350 light-years from Earth. Although the nebula is spectacular when seen through an ordinary telescope, what can be seen using visible light is only a small part of a cloud of gas in which stars are forming. Most of the action is deeply embedded in dust clouds and to see what is really happening astronomers need to use telescopes with detectors sensitive to the longer wavelength radiation that can penetrate the dust. VISTA has imaged the Orion Nebula at wavelengths about twice as long as can be detected by the human eye.

VISTA — the Visible and Infrared Survey Telescope for Astronomy — is the latest addition to ESO’s Paranal Observatory. It is the largest survey telescope in the world and is dedicated to mapping the sky at infrared wavelengths. The large (4.1-meter) mirror, wide field of view and very sensitive detectors make VISTA a unique instrument. This dramatic new image of the Orion Nebula illustrates VISTA’s remarkable powers.

As in the many visible light pictures of this object, the new wide field VISTA image shows the familiar bat-like form of the nebula in the center of the picture as well as the fascinating surrounding area. At the very heart of this region lie the four bright stars forming the Trapezium, a group of very hot young stars pumping out fierce ultraviolet radiation that is clearing the surrounding region and making the gas glow. However, observing in the infrared allows VISTA to reveal many other young stars in this central region that cannot be seen in visible light.   These youthful stars eject streams of gas with typical speeds of 700,000 km/hour and many of the red features highlight the places where these gas streams collide with the surrounding gas, causing emission from excited molecules and atoms in the gas. There are also a few faint, red features below the Orion Nebula in the image, showing that stars form there too, but with much less vigor. These strange features are of great interest to astronomers studying the birth and youth of stars.

Below is a cool video of the new look at Orion…

- Adapted from an ESO news announcement

Orion in the southern evening sky; click image to enlarge

Orion in the southern evening sky; click image to enlarge

Doorstep Astronomy: You can take a gander at this star factory for yourself with nothing more than your unaided eyes – even from light polluted suburbs! Just face towards the southern sky all evening long and look for Orion constellation’s distinctive row of three stars. This trio marks the belt of the mighty hunter. Just below the belt is Orion’s sword – which is a near vertical row of another three fainter stars.

Look closely at the middle star, and you will notice that it looks kind of fuzzy compared to the ones beside it. You have found Orion’s nebula – a giant cloud of gas and dust nearly 1400 light years away from us.

Binoculars and even a small telescope will begin to reveal the cloud’s beautiful flower-like structure composed of a tiny, tight cluster of blue-white stars surrounded by a grey-green mist. The French comet-hunter Charles Messier made an accurate sketch of its main features in the mid-eighteenth century and gave it the number 42 in his famous catalogue.

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New Night Sky Episode

Written by The Night Sky Guy on January 16, 2010 – 11:52 am -

If you missed it last night here is my latest episode where we talk about tracking down Orion constellation and its most celebrated star – Betelgeuse. Just don’t say that name three times ;-)

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Monster Star Comes into Focus

Written by The Night Sky Guy on July 29, 2009 – 9:13 am -

Stars are so far away that most telescopes, even some of the largest, cannot resolve them into disks. They simply appear as a point of light. Now all that is changing, thanks to a new technique where the power of three giant telescopes can be combined as one.  Now astronomers have taken the sharpest view of a dying mammoth star ever made (see image on right).  Even with Earth’s turbulent, image-distorting atmosphere in the way, the resolution of the red giant Betelgeuse is as fine as 37 milliarcseconds, which is roughly the size of a tennis ball on the International Space Station (ISS), as seen from the ground.

For the first time they could show, how the gas is moving in different areas over the surface of a distant star. This latest news on the famous bright star, Betelgeuse, in the constellation Orion, comes on the heels of the discovery last month that the same star is skrinking in size. This new accomplishment was made possible by combining three 1.8 m telescopes as an interferometer, giving the astronomers the resolving power of a virtual, gigantic 48 m telescope. Using the ESO VLT Interferometer in Chile, they discovered that the gas in the dying star’s atmosphere is vigorously moving up and down, but the size of such “bubbles” is as large as the star itself. These colossal bubbles are a key for pushing material out of the star’s atmosphere into space, before the star explodes as a supernova.

Artists impression, showing how a vast amount of material is flung out from Betelgeuse into space.

Artist's impression, showing how a vast amount of material is flung out from Betelgeuse into space.

Betelgeuse in Orion

Betelgeuse in Orion

When one looks up the clear night sky in winter, it is easy to spot a bright, orange star on the shoulder of the constellation Orion (the Hunter) even in light-flooded big cities. That is Betelgeuse. It is a giant star, which is so huge as to almost reach the orbit of Jupiter, swallowing the inner planets Mercury, Venus, Earth, and Mars, when placed at the center of the solar system. It is also glaringly bright, emitting 100 000 times more light than the Sun. Betelgeuse is a so-called red supergiant and approaching the end of its short life of several million years. Red supergiants shed a large amount of material made of various molecules and dust, which are recycled for the next generation of stars and planets possibly like the Earth. As a matter of fact, Betelgeuse is losing material equivalent to the Earth’s mass every year.

The death of the mammoth star, which is expected in the next few thousand to hundred thousand years, will be accompanied by cosmic fireworks known as a supernova like the famous SN1987A. However, as Betelgeuse is much closer to the Earth than SN1987A, the supernova can be clearly seen with the unaided eye, even in daylight.

- Adapted from material taken from a news announcement by the Max-Planck-Institut for Radio Astronomy

click image to enlarge

click image to enlarge

Doorstep Astronomy: You can check out Betelgeuse and its host constellation Orion in the early morning sky. Look towards the eastern horizon about a half hour before local sunrise and you should be able to make out the belt of three stars and the distinct orange-hued Betelgeuse sitting to their upper left. If the glare from the dawn is giving you a hard time finding the red giant, then use the super-bright, star-like Venus (brightest star in the sky) and just scan over to its right side and you should see 429 light year distant Betelgeuse stand out.




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Giant Star in Sky Shrinking

Written by The Night Sky Guy on June 9, 2009 – 4:16 pm -

The red supergiant star Betelgeuse, the bright reddish star in the constellation Orion, has steadily shrunk over the past 15 years, according to University of California, Berkeley, researchers. Long-term monitoring shows that Betelgeuse (bet’ el juz), which is so big that in our solar system it would reach to the orbit of Jupiter, has shrunk in diameter by more than 15 percent since 1993.
Since Betelgeuse’s radius is about five astronomical units, or five times the radius of Earth’s orbit, that means the star’s radius has shrunk by a distance equal to the orbit of Venus. 

Hubbles View of Betelgeuses disk

Hubble's View of Betelgeuse's disk



Despite Betelgeuse’s diminished size, astronomers pointed out that its visible brightness, or magnitude, has shown no significant dimming over the past 15 years.

“But we do not know why the star is shrinking,” one of the researchers said. “Considering all that we know about galaxies and the distant universe,there are still lots of things we don’t know about stars, including what happens as red giants near the ends of their lives.”

Courtesy of 214th Meeting of the American Astronomical Society in Pasedena, California

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