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Posts Tagged ‘star’

Asteroid To Black Out A Bright Star


Credit: IOTA / Stellarium / Sky & Telescope

Credit: IOTA / Stellarium / Sky & Telescope

Millions of people around New York City and points north can plan to watch a faint asteroid dramatically black out a bright naked-eye star very late next Wednesday night (the night of March 19–20).

And if you’re anywhere from the Carolinas to Nova Scotia to Winnipeg, a citizen-science project is asking you to keep watch too!

Get ready for the best and brightest “asteroid occultation” ever predicted for North America. Late on the night of March 19–20, the faint asteroid Erigone (eh-RIG-uh-nee) will briefly eclipse the bright naked-eye star Regulus for more than 20 million people in the New York metropolitan area and parts of Long Island, New Jersey, Connecticut, upstate New York, and Ontario. The star will vanish from sight for up to 14 seconds around 2:06 a.m. EDT on the morning of the 20th for New Yorkers, and a minute or two later farther north.

If the sky is clear, Regulus will be a cinch for anyone to spot — no astronomy experience required! Around 2 a.m. or a bit before, go out and face the Moon. Extend your arms straight out to your sides. Regulus will be straight above your right hand, roughly as high as the Moon is. It’s the brightest star in that area.

“Regulus shines right through moonlight and light pollution that’s in the sky — even the light pollution over a city like New York,” says Alan MacRobert, a senior editor at Sky & Telescope magazine. “Just be sure to shield your eyes against any glary lights, and Regulus should be easy to find.”

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Rocks Around The Clock: Asteroids Pound Tiny Star

February 19, 2014 Leave a comment

Artist's impression. Credit: NASA/JPL-Caltech

Artist’s impression. Credit: NASA/JPL-Caltech

Scientists using CSIRO’s Parkes telescope and another telescope in South Africa have found evidence that a tiny star called PSR J0738-4042 is being pounded by asteroids — large lumps of rock from space.

“One of these rocks seems to have had a mass of about a billion tonnes,” CSIRO astronomer and member of the research team Dr Ryan Shannon said.

PSR J0738-4042 lies 37,000 light-years from Earth in the constellation of Puppis.

The environment around this star is especially harsh, full of radiation and violent winds of particles.

“If a large rocky object can form here, planets could form around any star. That’s exciting,” Dr Shannon said.

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When A Black Hole Shreds A Star, A Bright Flare Tells The Story

February 19, 2014 Leave a comment

Computer simulation. Image by James Guillochon

Computer simulation. Image by James Guillochon

Enrico Ramirez-Ruiz uses computer simulations to explore the universe’s most violent events, so when the first detailed observations of a star being ripped apart by a black hole were reported in 2012 (Gezari et al., Nature), he was eager to compare the data with his simulations. He was also highly skeptical of one of the published conclusions: that the disrupted star was a rare helium star.

“I was sure it was a normal hydrogen star and we were just not understanding what’s going on,” said Ramirez-Ruiz, a professor of astronomy and astrophysics at the University of California, Santa Cruz.

In a paper accepted for publication in the Astrophysical Journal and available online at arXiv.org, Ramirez-Ruiz and his students explain what happens during the disruption of a normal sun-like star by a supermassive black hole, and they show why observers might fail to see evidence of the hydrogen in the star. First author and UCSC graduate student James Guillochon (now an Einstein Fellow at Harvard University) and undergraduate Haik Manukian worked with Ramirez-Ruiz to run a series of detailed computer simulations of encounters between stars and black holes.

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Spanish Researchers Discover The First Black Hole Orbiting A ‘Spinning’ Star

January 17, 2014 Leave a comment

Spanish scientists have discovered the first binary system ever known to consist of a black hole and a ‘spinning’ star —or more accurately, a Be-type star. Although predicted by theory, none had previously been found. The observations that led to the discovery were performed with the Liverpool and Mercator telescopes at the Observatorio del Roque de los Muchachos (Canary Islands, Spain). The discovery is published today in Nature.

Be-type stars are quite common across the Universe. In our Galaxy alone more than 80 of them are known in binary systems together with neutron stars. “Their distinctive property is their strong centrifugal force: they rotate very fast, close to their break-up speed. It is like they were cosmic spinning tops” says Jorge Casares from the Instituto de Astrofísica de Canarias (IAC) and La Laguna University (ULL). Casares is the lead author and an expert in stellar-mass black holes (he presented the first solid proof of their existence back in 1992).

The newly discovered black hole orbits the Be star known as MWC 656, located in the constellation Lacerta (the Lizard) —8,500 light years from Earth. The Be star rotates so fast that its surface speed exceeds 1 million kilometres per hour.

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Hubble Watches Super Star Create Holiday Light Show

December 18, 2013 Leave a comment

Image Credit: NASA/ESA/Hubble Heritage (STScI/AURA)-Hubble/Europe Collab

Image Credit: NASA/ESA/Hubble Heritage (STScI/AURA)-Hubble/Europe Collab

This festive NASA Hubble Space Telescope image resembles a holiday wreath made of sparkling lights. The bright southern hemisphere star RS Puppis, at the center of the image, is swaddled in a gossamer cocoon of reflective dust illuminated by the glittering star. The super star is ten times more massive than our sun and 200 times larger.

RS Puppis rhythmically brightens and dims over a six-week cycle. It is one of the most luminous in the class of so-called Cepheid variable stars. Its average intrinsic brightness is 15,000 times greater than our sun’s luminosity.

The nebula flickers in brightness as pulses of light from the Cepheid propagate outwards. Hubble took a series of photos of light flashes rippling across the nebula in a phenomenon known as a “light echo.” Even though light travels through space fast enough to span the gap between Earth and the moon in a little over a second, the nebula is so large that reflected light can actually be photographed traversing the nebula.

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Researchers Find That Bright Nearby Double Star Fomalhaut Is Actually A Triple

October 8, 2013 Leave a comment

The nearby star system Fomalhaut – of special interest for its unusual exoplanet and dusty debris disk – has been discovered to be not just a double star, as astronomers had thought, but one of the widest triple stars known.

In a paper recently accepted for publication in the Astronomical Journal and posted today to the preprint server arXiv, researchers show that a previously known smaller star in its vicinity is also part of the Fomalhaut system.

Eric Mamajek, associate professor of physics and astronomy at the University of Rochester, and his collaborators found the triple nature of the star system through a bit of detective work. “I noticed this third star a couple of years ago when I was plotting the motions of stars in the vicinity of Fomalhaut for another study,” Mamajek said. “However I needed to collect more data and gather a team of co-authors with different observations to test whether the star’s properties are consistent with being a third member of the Fomalhaut system.”

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Sun Block For The Big Dog: Detection Of Titanium Oxide And Titanium Dioxide Around The Giant Star VY Canis Majoris


Credits: Molecule symbols: CDMS/T. Kamiński, Background image: NASA/ESA and R. Humphreys (University of Minnesota)

Credits: Molecule symbols: CDMS/T. Kamiński, Background image: NASA/ESA and R. Humphreys (University of Minnesota)

An international team of astronomers, including researchers from the Max Planck Institute for Radio Astronomy and from the University of Cologne, discovered two titanium oxides, TiO and TiO2, at radio wavelengths using telescope arrays in the USA and in France. The detection was made in the environment of VY Canis Majoris, a giant star close to the end of its life.

The discovery was made in the course of a study of a spectacular star, VY Canis Majoris or VY CMa for short, which is a variable star located in the constellation Canis Major (Greater Dog). “VY CMa is not an ordinary star, it is one of the largest stars known, and it is close the end of its life,” says Tomasz Kamiński from the Max Planck Institute for Radio Astronomy (MPIfR). In fact, with a size of about one to two thousand times that of the Sun, it could extend out to the orbit of Saturn if it were placed in the center of our Solar System.

The star ejects large quantities of material which forms a dusty nebula. The complexity of this nebula has been puzzling astronomers for decades. It has been formed as a result of stellar wind, but it is not understood well why it is so far from having a spherical shape. Neither is known what physical process blows the wind, i.e. what lifts the material up from the stellar surface and makes it expand. “The fate of VY CMa is to explode as a supernova, but it is not known exactly when it will happen”, adds Karl Menten, head of the “Millimeter and Submillimeter Astronomy” Department at MPIfR.

Full Story: http://www3.mpifr-bonn.mpg.de/public/pr/pr-tio-mar2013-en.html