The photo of a nearby star and its orbiting companion — whose temperature is like a hot summer day in Arizona — will be presented by Penn State Associate Professor of Astronomy and Astrophysics Kevin Luhman during the Signposts of Planets conference at NASA’s Goddard Space Flight Center on Oct. 20, 2011.

A paper describing the discovery will be published in the Astrophysical Journal.

“This planet-like companion is the coldest object ever directly photographed outside our solar system,” said Luhman, who led the discovery team. “Its mass is about the same as many of the known extra-solar planets — about six to nine times the mass of Jupiter — but in other ways it is more like a star. Essentially, what we have found is a very small star with an atmospheric temperature about cool as the Earth’s.”

Luhman classifies this object as a “brown dwarf,” an object that formed just like a star out of a massive cloud of dust and gas. But the mass that a brown dwarf accumulates is not enough to ignite thermonuclear reactions in its core, resulting in a failed star that is very cool. In the case of the new brown dwarf, the scientists have gauged the temperature of its surface to be between 80 and 160 degrees Fahrenheit — possibly as cool as a human.

(via Planet-sized object as cool as Earth revealed in record-breaking photo)

Darkest Planet Found: Coal-Black, It Reflects Almost No Light

It may be hard to imagine a planet blacker than coal, but that’s what astronomers say they’ve discovered in our home galaxy with NASA’s Kepler space telescope.

Orbiting only about three million miles out from its star, the Jupiter-size gas giant planet, dubbed TrES-2b, is heated to 1,800 degrees Fahrenheit (980 degrees Celsius). Yet the apparently inky world appears to reflect almost none of the starlight that shines on it, according to a new study.

“Being less reflective than coal or even the blackest acrylic paint—this makes it by far the darkest planet ever discovered,” lead study author David Kipping said.

“If we could see it up close it would look like a near-black ball of gas, with a slight glowing red tinge to it—a true exotic amongst exoplanets,” added Kipping, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

(via National Geographic)

Star Found Shooting Water “Bullets”

Seven hundred and fifty light-years from Earth, a young, sunlike star has been found with jets that blast epic quantities of water into interstellar space, shooting out droplets that move faster than a speeding bullet.

The discovery suggests that protostars may be seeding the universe with water. These stellar embryos shoot jets of material from their north and south poles as their growth is fed by infalling dust that circles the bodies in vast disks.

“If we picture these jets as giant hoses and the water droplets as bullets, the amount shooting out equals a hundred million times the water flowing through the Amazon River every second,” said Lars Kristensen, a postdoctoral astronomer at Leiden University in the Netherlands.

“We are talking about velocities reaching 200,000 kilometers [124,000 miles] per hour, which is about 80 times faster than bullets flying out of a machine gun,” said Kristensen, lead author of the new study detailing the discovery, which has been accepted for publication in the journal Astronomy & Astrophysics.

(via National Geographic)

Strangely behaving supernovae leave physicists bemused

Supernovae are in the news this week, as two papers in the latest release from Nature provide fresh perspectives on stellar explosions old and new. The old one is Supernova 1987A, the closest one in the age of modern astronomy, which has recently undergone a brightening that indicates a key transition in its evolution has taken place. The new one is actually an entirely new category of supernova, represented by four examples. The output of this new category is heavily biased towards the blue end of the spectrum, it’s ten times brighter than a Type Ia supernova, and we aren’t sure what could possibly be powering it.

Some basic background on supernovae will make it easier to understand both stories. The initial collapse of a star creates a tremendous explosion, one heralded by the arrival of neutrinos and high-energy photons. But the fusion events that accompany the explosion also produce some unstable radioactive isotopes, such as nickel-56 and -57 and titanium-44. Both immediately after the explosion and for the following several years, the remnant of the supernova is primarily lit by energy released as these isotopes decay. Only after a few decades do other processes, primarily the interaction between the expanding shell of the explosion and the stellar environment, begin to dominate the light seen at the site of the supernova.

(via Ars Technica)

NASA’s Kepler finds its first five planets - an odd assortment - CSMonitor.com

NASA’s planet-hunting telescope Kepler has bagged its first quarry: five new planets Neptune’s size and larger, including one with the density of Styrofoam, making it one of the lightest planets yet found.

In addition to the new planets, Kepler results suggest that the light output from two-thirds of some 43,000 sun-like stars in its field of view is virtually as stable as the sun’s output.

That seemingly obscure observation suggests that the majority of stars potentially are as hospitable to life as Earth’s sun, assuming there was an Earth-like planet orbiting at the right distance from the star.

“If most stars are quiescent, that increases the havens for life in the universe,” says astronomer Caty Pilachowski of Indiana University. The reason: Periodic strong outbursts of radiation from a star could sterilize a planet’s surface, even if the planet orbited the star in the so-called habitable zone.

That zone represents distances where any water on a planet’s surface would receive just enough heat to remain liquid and stable on the planet’s surface.

Quiescent stars mean “we’re more likely to have habitats where life can evolve and increases our chances of finding that life down the road,” she says.

unknownskywalker:

Backlit dust lanes in NGC 7049

NGC 7049 resides in the constellation of Indus, in the southern sky. A family of globular clusters appears as glittering spots dusted around the galaxy halo. Astronomers study the globular clusters in NGC 7049 to learn more about its formation and evolution. The dust lanes, which appear as a lacy web, are dramatically backlit by the millions of stars in the halo of NGC 7049.

Source: ESA/Hubble

NASA’s Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system. The discovery of this so-called exoplanet is based on more than eight months of data collected by the spacecraft from May 2009 to early January 2010. This video is narrated by Kepler Deputy Science Team Lead Natalie Batalha.

scienceisbeauty:

Pulses from neutron star (rear) are slowed as they pass near foreground white dwarf. This effect allowed astronomers to measure masses of the system.

Source: Astronomers Discover Most Massive Neutron Star Yet Known, National Radio Astronomy Observatory, National Science Foundation

unknownskywalker:

First planet of extragalactic origin discovered

A planet with a minimum mass 1.25 times that of Jupiter has been discovered orbiting a star of extragalactic origin. It is part of the so-called Helmi stream — a group of stars that originally belonged to a dwarf galaxy that was devoured by our galaxy, the Milky Way, in an act of galactic merger about 6-9 billion years ago.

The star is known as HIP 13044, and it lies about 2000 light-years from Earth in the southern constellation of Fornax. Using the MPG/ESO 2.2-metre telescope at La Silla Observatory in Chile, the astronomers detected the planet, called HIP 13044 b, by looking for the tiny telltale wobbles of the star caused by the gravitational tug of an orbiting companion.

HIP 13044 b is very near to its host star, at about 0.055 times the Sun-Earth distance and completes an orbit in only 16.2 days. The planet’s orbit might initially have been much larger, but that it moved inwards during the red giant phase. HIP 13044 b is also one of the few exoplanets known to have survived the red giant phase of stellar evolution. The star has now contracted again and is burning helium in its core.

The star is rotating relatively quickly for an horizontal branch star, likely because it swallowed its inner planets during the red giant phase, which would make it spin more quickly. Although HIP 13044 b has escaped the fate of these inner planets so far, the star will expand again in the next stage of its evolution. HIP 13044 b may therefore be about to be engulfed by the star.

This could also foretell the demise of our outer planets — such as Jupiter — when the Sun approaches the end of its life.

Image: Artist’s impression of HIP 13044 b and its parent star. This visible light wide-field image shows the star HIP 13044 at the exact center, but the planet is much too faint to be seen in this image.

• Official source: ESO [video]

unknownskywalker:

Collecting brown dwarfs in the night sky

That green dot in the middle of this image might look like an emerald amidst glittering diamonds, but it is actually a dim star belonging to a class called brown dwarfs. This particular object, named WISEPC J045853.90+643451.9 after its location in the sky, is the first ultra-cool brown dwarf discovered by NASA’s Wide-field Infrared Survey Explorer (WISE).

This view shows three of WISE’s four infrared channels, color-coded blue, green and red, with blue showing the shortest wavelengths of infrared light and red, the longest. The methane in the atmospheres of brown dwarfs absorbs this color-coded blue light, and the objects themselves are too faint to give off a lot of the red light. That leaves green. As can be seen in this picture, the little green dot of a brown dwarf stands out against the sparkly, hotter blue stars.

The brown dwarf is located 18 to 30 light-years away in the northern constellation of Camelopardalis. This is one of the coolest brown dwarfs known, with a temperature of roughly 600 °K, or 620 °F.

• Source: NASA/JPL

fuckyeahphysics:

invaderxan:

Internal structure of a red giant star. Increased radiation pressure from that shell around the star’s core is what’s thought to make stars expand into red giants. Red giants have hotter cores which power higher rates of fusion, causing red giants to have hundreds to thousands of times the luminosity they had as main sequence stars.

unknownskywalker:

Unravelling the Mystery of Massive Star Birth

For the first time astronomers have imaged the inner regions of a dusty disc closely encircling a massive baby star, which is now fully formed, providing direct evidence that massive stars form in the same way as smaller ones. All stars form in the same way, regardless of mass.

The team of astronomers looked at an object known by the cryptic name of IRAS 13481-6124. About twenty times the mass of our Sun and five times its radius, the young central star, which is still surrounded by its pre-natal cocoon, is located in the constellation of Centaurus, about 10,000 light-years away.

Circumstellar discs are an essential in the formation of low-mass stars such as our Sun. However, it is not known whether such discs are also present during the formation of stars more massive than about ten solar masses, where the strong light emitted might prevent mass falling onto the star. For instance, it has been proposed that massive stars might form when smaller stars merge.

In order to discover the disc, astronomers employed ESO’s Very Large Telescope Interferometer (VLTI). By combining light from three of the VLTI’s 1.8-metre Auxiliary Telescopes with the AMBER instrument, this facility allows astronomers to see details equivalent to those a telescope with a mirror of 85 metres in diameter would see. The resulting resolution is equivalent to picking out the head of a screw on the International Space Station, or more than ten times the resolution possible with current visible-light telescopes in space.

The astronomers conclude that the system is about 60,000 years old, and that the star has reached its final mass. Because of the intense light of the star — 30,000 times more luminous than our Sun — the disc will soon start to evaporate. The flared disc extends to about 130 times the Earth–Sun distance — or 130 astronomical units (AU) — and has a mass similar to that of the star, roughly twenty times the Sun. In addition, the inner parts of the disc are shown to be devoid of dust.

Image: (top) Artist’s impression. | Actual image: The disc around IRAS 13481-6124

Image Credit: ESO

unknownskywalker:

Record-breaking X-ray blast briefly blinds space observatory

A blast of the brightest X-rays ever detected from beyond our Milky Way galaxy’s neighborhood temporarily blinded the X-ray eye on NASA’s Swift space observatory earlier this summer. The X-rays traveled through space for 5-billion years before slamming into and overwhelming Swift’s X-ray Telescope on June 21.

The blindingly bright blast came from a gamma-ray burst — a violent eruption of energy from the explosion of a massive star morphing into a new black hole. Although the Swift satellite was designed specifically to study gamma-ray bursts, the instrument was not designed to handle an X-ray blast this bright. The burst, named GRB 100621A, is the brightest X-ray source that Swift has detected since the observatory began X-ray observation in early 2005.

The burst was so bright when it first erupted that the data-analysis software shut down. So many photons were bombarding the detector each second that it just couldn’t count them quickly enough.

The blast’s X-ray brightness was 143,000 X-ray photons per second, which is more that 140 times brighter than the brightest continuous X-ray source in the sky — a neutron star that is more than 500,000 times closer to Earth than the gamma-ray burst, and that sends only 10,000 photons per second.

Gamma-ray bursts typically begin with a bright flash of high-energy gamma-rays and X-rays, then fade away like a fireworks display, sometimes leaving behind a disappearing afterglow in less-energetic wavelengths, including optical and ultraviolet. Surprisingly, although the energy from this burst was the brightest ever in X-rays, it was merely ordinary in optical and ultraviolet wavelengths.

Image: The brightest gamma-ray burst ever seen in X-rays temporarily blinded Swift’s X-ray Telescope on June 21.

Source: Pennsylvania State University | See also: NASA Goddard Space Flight Center, SPACE.com, Bad Astronomy

Image: An artist’s illustration of the Upsilon Andromedae A system, where three Jupiter-type planets orbit the yellow-white star Upsilon Andromedae A. Astronomers have recently discovered that not all planets orbit this star in the same plane, as the major planets in our solar system orbit the Sun. The orbits of two of the planets are inclined by 30 degrees with respect to each other. Such a strange orientation has never before been seen in any other planetary system. This surprising finding will impact theories of how planetary systems form and evolve, say researchers. It suggests that some violent events can happen to disrupt planets’ orbits after a planetary system forms. The discovery was made by joint observations with the Hubble Space Telescope, the Hobby-Eberly Telescope, and other ground-based telescopes. Credit: NASA, ESA and A. Feild (STScI) / B. McArthur (University of Texas at Austin).

Disturbing the Habitable Zone

It’s AAS week in Miami, and the American Astronomical Society usually gives us plenty to talk about. Inclined orbits, for one thing. In our Solar System, the process of planetary formation seems relatively intuitive. The eight major planets orbit largely in the same plane, reinforcing the idea that the cloud of gas that collapsed to form the Sun contained leftover material that formed into a planet-yielding disk. We can point to outer system objects like Pluto (and certainly Sedna) as exceptions, but they’re much further out and subject to gravitational influences that this model can account for.

But as Barbara McArthur (University of Texas at Austin) and team told an AAS session yesterday, the star Upsilon Andromedae A has yielded a different result. We already knew that three Jupiter-class planets orbited the star, some 44 light years away and a bit younger and more massive than our Sun. But McArthur’s team now has determined the mass of two of the three known planets, and has produced the startling finding that the orbits of planets c and d are inclined by 30 degrees with respect to each other.

This is a fascinating find, and represents the first time that the mutual inclination of two planets orbiting another star has ever been measured. And McArthur points to the work’s significance:

“Most probably Upsilon Andromedae had the same formation process as our own solar system, although there could have been differences in the late formation that seeded this divergent evolution. The premise of planetary evolution so far has been that planetary systems form in the disk and remain relatively co-planar, like our own system, but now we have measured a significant angle between these planets that indicates this isn’t always the case.”

(via Centauri Dreams)