Will the Star Betelgeuse become a Supernova in 2012?

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(Above:   planets and our sun shown in order of size)
Betelgeuse, also known as Alpha Orionis, is a red supergiant star that could become a supernova in the not-too-distant future.
Betelgeuse, pronounced bet-el-jooz (not Beetlejuice), is a red supergiant star easily found in the shoulder of Orion.
Betelgeuse's giant size makes it one of the only stars visible through Hubble as more than a point of light.

Will Betelgeuse Become a Second Sun in 2012?

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By Natalie Wolchover  'Life's Little Mysteries' Staff Writer
21 January 2011    

Orion Constellation

Several online news sites have reported that the star Betelgeuse will undergo a supernova explosion next year – yes, that's 2012 – and shine as brightly in the sky as a second sun.

But according to scientists, it's all nonsense.

"Betelgeuse is losing mass, and it will turn into a supernova soon, but that 'soon' means on an astronomical time scale: It's as likely to happen a million years from now as it is tomorrow," University of Illinois astronomer Jim Kaler told Life's Little Mysteries..

No one knows quite when Betelgeuse, which is about 10 to 20 times more massive than our sun, will explode. But when it does detonate, the star, which forms the constellation Orion's right shoulder, won't look like a second sun in our sky, Kaler said.

"The supernova would hit somewhere around the brightness of a crescent moon," said Kaler, who has focused his research on dying stars since the 1950s. "It would definitely be visible in full daylight, and it would cast shadows. It might scare the crap out of people to be honest, but it would be nowhere near as bright as the sun."

And there isn't any reason to be afraid of this particular star explosion.

When a star goes supernova, it blasts a huge amount of matter and radiation outward through space. If such an event were to happen within 30 light-years from here, it would significantly damage the Earth's ozone layer and cause mass extinctions. One light-year is the distance that light travels in a year, about 6 trillion miles (10 trillion kilometers).

Some supernovas produce gamma-ray bursts as well, which are intense and dangerous blasts of radiation. But Betelgeuse is about 600 light-years away—too far away to threaten Earth—and it will become what scientists describe as a "core-collapse type II supernova."

"Those definitely don't produce gamma-ray bursts," said Kaler.

So what will happen when Betelgeuse explodes — whenever that may be?

"Well, it will make an awful mess of the constellation Orion," remarked Kaler.


Share Credit: NASA
http://www.lifeslittlemysteries.com/will-betelgeuse-really-become-second-sun-1260/

A Red Giant in Orion Is Surprisingly Shrinking

19 June 2009 - Kelly Whitt

Facts About Betelgeuse
Betelgeuse is one of the largest stars known. If it was placed in the position of the sun in Earth's solar system, it would extend out to the orbit of Jupiter. Betelgeuse lies about 640 light-years away in the constellation Orion the Hunter. Best viewed in winter, Betelgeuse is the bright upper left star in the form of Orion, marking his right shoulder.

Measurements of Betelgeuse have been quite difficult, because the star has a strong wind that is ejecting large quantities of dust, making it hard to locate the actual surface. UC Berkeley’s Infrared Spatial Interferometer (ISI) has helped nail down these measurements.

Betelgeuse is a variable star, and although it is given the alpha designation, the star in the lower right portion of Orion, known as Rigel, is usually brighter. In general, the magnitude of Betelgeuse is 0.45. Rigel is 0.18.

Betelgeuse is approximately 8.5 million years old, much younger than the sun. (The sun is about 4.6 billion years old.) But larger stars live shorter lives, and Betelgeuse could go supernova at any time. Betelgeuse shines 135,000 times brighter than the sun. When it explodes, that brightness will increase exponentially, allowing the blast to be seen in daylight as it shines as brightly as a crescent moon.

Betelgeuse's Surprise is It's Shrinking
Studies by researchers at the University of California, Berkeley, have discovered that Betelgeuse has shrunk steadily over the past 15 years. The circumference of Betelgeuse has diminished by 15 percent since 1993, which would be about equal to the distance of Venus's orbit.

"To see this change is very striking," said Charles Townes, a UC Berkeley professor emeritus of physics who won the 1964 Nobel Prize in Physics for inventing the laser and the maser, a microwave laser. "We will be watching it carefully over the next few years to see if it will keep contracting or will go back up in size."

Despite the change in Betelgeuse's size, the star has not dimmed over this same period of time.

Edward Wishnow, a research physicist at UC Berkeley’s Space Sciences Laboratory, is also involved in the studies. "We do not know why the star is shrinking," Wishnow says. "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."

Townes explains the benefits of the ISI observations. "We observe around 11 microns, the mid-infrared, where this long wavelength penetrates the dust and the narrow bandwidth avoids any spectral lines, and so we see the star relatively undistorted," said Townes. "We have also had the good fortune to have an instrument that has operated in a very similar manner for some 15 years, providing a long and consistent series of measurements that no one else has. The first measurements showed a size quite close to [original 1921 measurements], but over 15 years, it has decreased in size about 15 percent, changing smoothly, but faster as the years progressed."

What will Betelgeuse do next? Astronomers must wait and watch for that answer.

Source: UC Berkeley
http://www.suite101.com/content/facts-about-the-star-betelgeuse-a123985