Skip to comments.Object Survives Being Swallowed by a Star
Posted on 08/03/2006 10:40:47 AM PDT by NormsRevenge
Long before the Bible's tale of Jonah being swallowed by a whale, a small wannabe star has emerged intact after being engulfed by a neighboring giant star, scientists say.
The victim was a brown dwarf, a failed star too small to sustain the nuclear reactions that ignites regular stars. The purpetrator was a red giant, an ancient star that once resembled our Sun but which puffed up to enormous size after its hydrogen fuel was depleted. The red giant has since expelled most of its gas into space and transformed into a dense, Earth-sized star called a white dwarfs.
Using the European Southern Observatory's Very Large Telescope, astronomers spied the binary system that remains: the brown and white dwarfs. The brown dwarf is thought to have survived being swallowed by its companion during the white dwarf's red giant phase.
The discovery, detailed in the Aug. 3 issue of the journal Nature, provides the first solid evidence that an object as small as a brown dwarf-which is just one step up from giant planet mass-can survive another star's red giant phase. Previously, only red dwarfs, stars with masses about a third that of our sun, have been known to withstand such events.
Called WD 0137-349, the system is located about 300 light-years from Earth. Its two dwarfs are separated by only a few thousandths the distance between Earth and the Sun and the objects rotate around in each other in about 2 hours.
In the past, the two objects were farther part, but the temporary engulfment by the red giant's gas envelope is thought to have slowed down the orbital speed of the brown dwarf, causing it to spiral inwards towards the center of its larger neighbor.
Although too small to become a star, the brown dwarf was still big enough to avoid vaporization when it was engulfed.
Had it been less than 20 Jupiter masses, "it would have evaporated during this phase," said lead author Pierre Maxted of Keele University in England.
But there's another reason the brown dwarf survived. Scientists think the failed star sped up its companion's red giant phase, the way enzymes speed up biological reactions while remaining unharmed. When it was engulfed, the brown dwarf amassed matter from the red giant's gas envelope, which it then radiated off into space. By doing so, it shortened its companion's red giant phase dramatically.
"Normal single red giants that don't swallow anything probably last about 100 million years, but in this system, it may have only lasted a few decades," study team member Matt Burleigh of the University of Leicester in England told SPACE.com.
The brown dwarf's reprieve from destruction is only temporary, however. Its orbit is slowly shrinking, and in about 1.4 billion years, it will be close enough for the white dwarf to siphon gas from surface. When this happens, the brown dwarf will slowly shrink in mass, while the accumulating matter on the white dwarf will trigger massive thermonuclear explosions called novas every few years.
In about 5 or 6 billion years, what happened in WD 0137-349 will repeat in our solar system. Our sun will run out of hydrogen and become a red giant, expanding until its diameter is about the size of Earth's orbit. Unlike the brown dwarf, however, our planet is not expected to survive-at least not in its present form.
"It's an ongoing debate whether the Earth will be swallowed up or not," Burleigh said. "But what's for certain to happen is that the Earth's atmosphere and seas will be boiled off. Even if it doesn't quite get engulfed, Earth will be pretty much lifeless."
Several million years after the red giant phase, our Sun will shrink and become a white dwarf. At this point, the orbits of Jupiter and Saturn will double or even triple since the new white dwarf anchoring our solar system will be much less massive than our Sun is now.
Planets farther out might not be so lucky; they could become untethered and float off into interstellar space, Burleigh said.
Thank goodness there is no video (that I know of). Them Hiltons do know how to party tho. ;-)
Why does that DirecTV commercial come to mind?
Oh, wait, that's Billion, not Million?
Phew, what a relief!
"The victim was a brown dwarf, a failed star too small to sustain..."
Laz, Xena--Sorry, netiquette demands I ping you, even though I only named you in jest.
1 full YOWZA! That was funny!
:') Talk about red giants, eh?
Retrograde satellites lose momentum to the parent body and slowly spiral inward, which puts an upper limit on the length of time the retrograde moons have spent as satellites, and obviously, will spend as satellites.Did Jupiter Bully Other Planets in Sibling Rivalry?One possible explanation, discussed in Thursday's issue of the journal Nature, is that Uranus and Neptune formed much closer to the center of the action than their current positions might indicate. In this scheme, Jupiter and Saturn were bullies of a protoplanetary playground, shoving the other two future giants out of the way.
by Robert Roy Britt
8 December 1999Jupiter gave birth to Uranus and NeptuneNot too long ago, scientists regarded the orbits that the planets circle our Sun as being the ones they were born in. Now they are realising that this is not the case. Uranus and Neptune may have migrated outwards and Jupiter may have come in from the outer cold. Scientists have always been slightly puzzled by the positions of Uranus and Neptune because in their present locations it would have taken longer than the age of the Solar System for them to form. Scientists from Queen's University suggest that the four giant planets started out as rocky cores in the Jupiter-Saturn region, and that the cores of Uranus and Neptune were tossed out by Jupiter's and Saturn's gravity.
by Dr David Whitehouse
8 December 1999Jupiter's Composition Throws Planet-formation Theories into DisarrayExamining four-year-old data, researchers have found significantly elevated levels of argon, krypton and xenon in Jupiter's atmosphere that may force a rethinking of theories about how the planet, and possibly the entire solar system, formed. Prevailing theories of planetary formation hold that the sun gathered itself together in the center of a pancake-shaped disk of gas and dust, then the planets begin to take shape by cleaning up the leftovers. In Jupiter's current orbit, 5 astronomical units from the sun, temperatures are too warm for the planetesimals to have trapped the noble gases. Only in the Kuiper belt -- a frigid region of the solar system more than 40 AU from the sun -- could planetesimals have trapped argon, krypton and xenon.
by Robert Roy Britt
Nov 17 1999
While lead researcher Tobias Owen does not put much stock in the idea that Jupiter might have migrated inward to its present position, other scientists on the team say the idea merits consideration. Owen expects the probes will find similarly high levels of noble gases in Saturn, Uranus and Neptune. Hints of these gases have even been found in the thick atmosphere of Venus, another planet now begging more study.Newfound Moons Tell Secrets of Solar SystemThe fact that most of the satellites' orbits are retrograde and eccentric speaks volumes about their origins: They had to have come from elsewhere, and been captured by the planets at some point. If they formed at the same time as the planets, from the spinning nebular disk, their orbits would be nearly circular and in the same direction as the planets' rotation, like the "regular" moons... In the case of the irregular satellites, they could not have shifted from an orbit around the Sun to an orbit around one of the giant planets without slowing down -- through friction in an atmosphere, perhaps; the influence of gravity; or a collision with another object... But there are two other possibilities for capture, Dr. Nesvorny said. One is that rapid growth of the core led to a corresponding increase in gravity, enough to pull down a nearby object. The other is that captured objects were a result of a collision between two planetesimals, the force of the collision being enough to dissipate the energy of at least one of them. Either of these two theories may be a more likely explanation for the satellites of Uranus and Neptune, which formed differently from Jupiter and Saturn, without the large amounts of gas.
by Henry Fountain
August 12, 2003
Planet Formation In Hundreds Of Years?The British astronomer W.H. McCrea concluded in the '60s, as others have since, that minor planets could not form by accretion inside the orbit of Jupiter because of its disruptive tidal effects, and R.A. Lyttleton showed in a fluid dynamic analysis of Jupiter's core that its rotation and accretion rates would cause it to become periodically unstable and fission to throw off excess mass. We're told that the gas giants don't have rock cores, but that has always struck me as preposterous, since even if they formed from pure gaseous concentrations initially, bodies of that size would surely attract heavier material thereafter. So conceivably gas giants formed rapidly in the way the Pittsburgh simulation depicts represent the first phase of a process that accumulates fast-spinning cores of heavier material that gets compressed down to rocky densities, and ejects them as a planet and comet factory.
Posted on January 27, 2003
I hafta ask...how does Paris get consistantly photoged from her 'side.' I mean does she walk thru life right to left only? Enquiring mind....
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