Stellary Starry Universe

 

Astronomers from NASA and Caltech are predicting a near-storm of Leonids in 2009 based on a surprising outburst of meteors just two weeks ago.

Dec. 4, 2008: Astronomers from Caltech and NASA say a strong shower of Leonid meteors is coming in 2009. Their prediction follows an outburst on Nov. 17, 2008, that broke several years of “Leonid quiet” and heralds even more intense activity next November.

“On Nov. 17, 2009, we expect the Leonids to produce upwards of 500 meteors per hour,” says Bill Cooke of the NASA Marshall Space Flight Center. “That’s a very strong display.”

Forecasters define a meteor storm as 1000 or more meteors per hour. That would make the 2009 Leonids “a half-storm,” says Jeremie Vaubaillon of Caltech, who successfully predicted a related outburst just a few weeks ago.

On Nov. 17, 2008, Earth passed through a stream of debris from comet 55P/Tempel-Tuttle. The gritty, dusty debris stream was laid down by the Leonids’ parent comet more than five hundred years ago in 1466. Almost no one expected the old stream to produce a very strong shower, but it did. Observers in Asia and Europe counted as many as 100 meteors per hour.

 

Source: Nasa Science – click here for full article

 

 

 

PARIS: Scientists believe they have found a way of shielding astronauts from a dangerous source of space radiation, thus lifting a major doubt clouding the dream to send humans to Mars.

 

Their breakthrough is reported this week in the journal Plasma Physics and Controlled Fusion – it takes forward ideas born in the golden age of science fiction, including a proton shield used in the TV show Star Trek, say the researchers.

Solar storms

Space weather is one of the greatest challenges facing a manned mission to the Red Planet. Even the shortest round trip (the distance varies between 55 million and more than 400 million kilometers) would take at least 18 months.

During this time, the crew would be exposed to sub-atomic particles that whiz through space, capable of slicing through DNA like a hot knife through butter, and boosting the risk of cancer and other disorders.

The peril has been known for nearly half a century, but has seemed insoluble because costs and technological difficulty. Some experts have toyed with the idea of shielding the crew with lead or massive tanks of water, but the price of lifting this load into orbit from Earth is mind-spinning.

Another idea, born in the 1960s, would be to swathe a spaceship with a replica of Earth’s own magnetic field. Our weak two-pole field deflects incoming cosmic rays, protecting life on Earth as well as astronauts in low Earth orbit.

 

Source: Cosmos Online – click here or title for full article

 

 

 

SYDNEY Australia: About three times a second, a 10,000-year-old stellar corpse sweeps a beam of gamma-rays toward Earth. Discovered by NASA’s Fermi Gamma-ray Space Telescope, this pulsar is the first known to blink in pure gamma rays.

 

“This is the first example of a new class of pulsars that will give us fundamental insights into how stars work,” says Stanford University’s Peter Michelson, principle investigator for the Large Area Telescope, one of the instruments aboard the orbiting observatory.

1,000 times the energy of our Sun

The new pulsar – detailed this week in the U.S. journal Science – lies within a supernova remnant known as CTA 1, located about 4,600 light-years away in the constellation Cepheus.

Its lighthouse-like beam sweeps Earth’s way every 316.86 milliseconds. The pulsar, which formed in a supernova explosion about 10,000 years ago, emits 1,000 times the energy of our Sun.

Pulsars were first discovered in 1967 by a student radio astronomer. The radio pulses recorded were uncannily steady – so much so that some astronomers wondered if they were picking up signals from extraterrestrial civilisations.

The correct explanation was even stranger: Pulsars are spinning neutron stars packing the mass of the Sun into a sphere about 20 km across. Whirling around thousands of times each hour, they beam radio pulses into the cosmos in the style of a rapid-fire lighthouse.

Source: Cosmos – click here for full article

 

SYDNEY: A nuclear explosion on the surface of a binary star within a planetary nebula has been detected – an event not witnessed for more than 100 years.

A paper on the finding, published in the Astrophysical Journal Letters, predicts that the combined mass of the two stars in the system may be high enough for the stars to eventually spiral into each other, triggering a much bigger double supernova explosion.

At the ends of their lives – prior to an all-encompassing supernova – some stars undergo nova explosions, caused by nuclear reactions on their surface.

“Runaway thermonuclear explosion”

“The star which erupted was a nova, an event caused when matter is transferred from one star in a close binary system onto its companion, eventually triggering a runaway thermonuclear explosion,” said Roger Wesson, lead astronomer behind the discovery at University College London in England.

Source: Cosmos Online – click here for full article

 

 

SYDNEY: New observations from NASA’s Spitzer Space Telescope suggest that icy planets are common around young, bright stars.

U.S. researchers say they have found evidence of icy planets – ranging in size from smaller than Pluto to as big as Neptune – around half of all ‘A-type’ stars in a nearby star cluster, called NGC 2232.

A-type stars are about twice as massive and twice as hot as the Sun.

“Like car crashes”

The researchers used data from NASA’s Spitzer Space Telescope and the ROSAT All-Sky Survey (a now defunct international satellite X-ray observatory) to observe A- and B-type stars that dwell 25 million light-years away in the constellation Monoceros, a faint group of stars between the Orion and Gemini constellations.

As they detail this week in the Astrophysical Journal, the researchers found one star ringed with a warm dusty disk where rocky planets might form, and 12 stars which had cold, dusty disks which they claim is made from the debris of icy planet-forming collisions.

“Planets grow by accreting small, kilometre-sized objects via collisions. Like car crashes, these collisions produce debris,” said lead author, U.S. astrophysicist Thayne Currie from the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts.

Source: Cosmos Online – click here for full article