Posts Tagged ‘keck’

Gamma-Ray Burst from WR 104?

Thursday, May 30th, 2013

Wow, a gamma-ray burst from a star 8,000 light years away could trash our atmosphere in seconds. It could happen today — or 500,000 years from now. That’s worse than the cable guy’s estimate.

I’m not changing my plans.

However, there are a bunch of astronomers who are working on the estimate in Australia and Hawaii. Bruce Dorminey’s piece in Forbes the other day puts all the details together:

Although WR 104, a Wolf-Rayet star some 8000 light years distant, has thus far remained largely quiescent, it is ripe to undergo a core-collapse supernova of the sort that could generate a seconds-long burst of gamma-rays that, in turn, might potentially wipe out a quarter of earth’s protective atmospheric ozone.

“We could see it go supernova anywhere from tomorrow to 500,000 years from now,” said Grant Hill, an astronomer at the W.M. Keck Observatory in Hawaii. “For all intents and purposes, the gamma-ray burst and optical photons from the supernova would arrive simultaneously.”

Later in the article, physicist Adrian Melott used the term “extinction event” — HULK NO LIKE THAT.


Big Bang Monday: “Protoplanet” LkCa 15 b

Monday, October 24th, 2011


Great work by astronomers Adam Kraus (University of Hawaii Institute for Astronomy) and Michael Ireland (Macquarie University and the Australian Astronomical Observatory) in finding the youngest planet ever.

“LkCa 15 b is the youngest planet ever found, about 5 times younger than the previous record holder,” said Kraus. “This young gas giant is being built out of the dust and gas. In the past, you couldn’t measure this kind of phenomenon because it’s happening so close to the star. But, for the first time, we’ve been able to directly measure the planet itself as well as the dusty matter around it.”

Kraus will be presenting the discovery at an Oct. 19 meeting at NASA’s Goddard Space Flight Center. The meeting follows the acceptance of a research paper on the discovery by Kraus and Ireland by The Astrophysical Journal.

The optical sleight of hand used by the astronomers is to combine the power of Keck’s Adaptive Optics with a technique called aperture mask interferometry. The former is the use of a deformable mirror to rapidly correct for atmospheric distortions of starlight. The latter involves placing a small mask with several holes in the path of the light collected and concentrated by a giant telescope. With that, the scientists can manipulate the light waves.

“It’s like we have an array of small mirrors,” said Kraus. “We can manipulate the light and cancel out distortions.” The technique allows the astronomers to cancel out the bright light of stars. They can then resolve disks of dust around stars and see gaps in the dusty layers where protoplanets may be hiding.

“Interferometry has actually been around since the 1800s, but through the use of adaptive optics has only been able to reach nearby young suns for about the last 7 years.” said Dr. Ireland. “Since then we’ve been trying to push the technique to its limits using the biggest telescopes in the world, especially Keck.”

The discovery of LkCa 15 b began as a survey of 150 young dusty stars in star-forming regions. That led to the more concentrated study of a dozen stars.

“LkCa 15 was only our second target, and we immediately knew we were seeing something new,” said Kraus. “We could see a faint point source near the star, so thinking it might be a Jupiter-like planet we went back a year later to get more data.”

In further investigations at varying wavelengths, the astronomers were intrigued to discover that the phenomenon was more complex than a single companion object.

“We realized we had uncovered a super Jupiter-sized gas planet, but that we could also measure the dust and gas surrounding it. We’d found a planet at its very beginning” said Kraus.

Drs. Kraus and Ireland plan to continue their observations of LkCa 15 and other nearby young stars in their efforts to construct a clearer picture of how planets and solar systems form.

Mirrors. Go figure.

Want to know how this was done? Get the details.