Author Topic: "Cool" Brown Dwarf, Small Star Found Near Earth  (Read 3796 times)

Online Laura

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"Cool" Brown Dwarf, Small Star Found Near Earth
« on: March 26, 2006, 11:48:44 AM »
http://news.nationalgeographic.com/news/2006/03/0323_060323_brown_dwarf.html

March 23, 2006—Astronomers have discovered a "cool" brown dwarf circling a star relatively close to Earth.



Brown dwarfs are neither stars nor planets. They are typically dozens of times more massive than Jupiter, the most massive planet in our solar system, but too small to shine like a star.

The newly discovered brown dwarf orbits a small star located about 12.7 light years from the sun, making it the third closest brown dwarf to Earth yet found.

"This is really very much in our neighborhood of the galaxy," said Laird Close, an astronomer at the University of Arizona in Tucson, whose team made the find.

Close added that this is a rare "cool" brown dwarf. It has a temperature of about 1,382ºF (750ºC). Most brown dwarfs are much hotter, he said.

Two other brown dwarfs have been discovered orbiting a star about 11.8 light years away. Of the seven brown dwarfs discovered within 20 light years of the sun, five have companion stars, the researchers say.

These findings hint that, at least close to the sun, brown dwarfs tend to pair up with stars rather than float in space alone.

"The interesting thing is the models for the most part suggest brown dwarfs should be free-floating in space, so it's a bit of a puzzle," Close said.

"The fact that we see more brown dwarfs as companions very near the sun suggests that our understanding of how brown dwarfs formed needs further theoretical work," he added.

The Arizona team discovered the brown dwarf with the European Southern Observatory's Very Large Telescope in Chile.

The discovery will be detailed in an upcoming issue of the Astrophysical Journal.

—John Roach
Illustration courtesy ESO
He who learns must suffer
And even in our sleep pain that cannot forget
Falls drop by drop upon the heart,
And in our own despair, against our will,
Comes wisdom to us by the awful grace of God.
Agamemnon, Aeschylus

schriss

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"Cool" Brown Dwarf, Small Star Found Near Earth
« Reply #1 on: April 02, 2006, 10:41:06 PM »
"The faint 9th magnitude red dwarf, currently 63 light-years away in the constellation Ophiucus, was recently discovered to be approaching our Solar System."
"poses no direct collision danger itself although its gravitational influence will likely scatter comets out of the Solar System's reservoir, the Oort cloud, sending some inbound."
They say it will reach our Solar system in 1 milion years. Maybe that's why NASA kept this secret for 6 years... (at least that's what another website claims)
http://antwrp.gsfc.nasa.gov/apod/ap991211.html

They quote Cassiopaeans:
http://www.mrinbetween.com/pages/Dark_Star.html

schriss

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"Cool" Brown Dwarf, Small Star Found Near Earth
« Reply #2 on: May 10, 2006, 08:21:30 PM »
Maybe it's the same thing Orions mentioned? It appears they were confused too, but they have a plan and will save us :D

Edit: no, that red dwarf is far away, while this "thing" obstructs planet movement :rolleyes:

Quote from: Orion Transmissions
October 12-November 19, 2005
We have a sombre purpose in requesting your attention at this early hour. We must reveal to you that your planet's movement is being obstructed by what appears to be a star. It is not a star. And it is not harmless. It must be intercepted before it closes in on this planet. We must work with great speed. We are as yet unable to transmit crucial data to planet Earth regarding this new development. What appears to be a 'star' is much more a serious threat to the planet than any pandemic, war or natural catastrophe. The planet will be in a state of chaos should this 'star' come near enough to become more than simply a threat. Scientists are aware of its presence but are not aware exactly what it is. We would caution those who 'know' to concentrate fully on defusing the threat to this planet.
Yes, it is not a star, but it appears as such and it also appears to be nearing the Earth, in relative terms. In essence, we are in a race against time.

December 11, 2005
Yes, yes. In our last transmissions, we alerted you to the existence of a moving 'object' in the skies which appears to be, but is not, a star moving toward this planet. While yes, there could be said to be something sinister about its presence, particularly its relatively close proximity to planet Earth, it is absolutely nothing to fear. It is, however, something to be aware of simply. It is out of human control to intercept this so-called star, either with guided missiles or with weapons. However, there are those of us who are working to redirect the path of this-well, one could more likely call it an asteroid than another star. It is highly likely that its path will be intercepted. However, even close proximity can generate Earthquakes, volcanic explosions and tremors beneath the Earth's surface. It is not only possible but probable that these will occur. Interception is not yet a certainty, but it is the plan.

Offline Shijing

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"Cool" Brown Dwarf, Small Star Found Near Earth
« Reply #3 on: May 04, 2010, 08:20:07 PM »
Here is a recent article about another nearby brown dwarf that was discovered recently:

http://www.newscientist.com/article/dn18757-dark-sun-is-one-of-our-nearest-neighbours.html

Quote
'Dark sun' is one of our nearest neighbours

A dim object less than 10 light years from Earth appears to be the closest brown dwarf yet found. The "star" is so cold that any residents on an orbiting planet would see a dark sun in their starry "daytime" sky.

The discovery suggests that brown dwarfs are common and that the objects could exist even closer to Earth.

Brown dwarfs have so little mass that they never get hot enough to sustain the nuclear fusion reactions that power stars like the sun. Still, they do shine, because they glow from the heat of their formation, then cool and fade.

Philip Lucas of the University of Hertfordshire in Hatfield, UK, and his colleagues discovered the brown dwarf, named UGPS 0722-05, from the infrared radiation it gives off. It is only about 9.6 light years from Earth, a bit more than twice as far as Proxima Centauri, our nearest star after the sun.

At that distance, it is the seventh closest star or star system to the sun. Not since 1947 have astronomers uncovered a new star so close to Earth.

Parallax view

"Great stuff!" says Todd Henry, a nearby-star researcher at Georgia State University in Atlanta, who was not part of the team. "This discovery is as cool as its temperature."

Lucas and his colleagues caution that their estimated distance is preliminary. It is based on parallax, which offers a reliable method of deducing a star's distance from Earth: if an observer on Earth measures the star's position in the sky and then looks at it again months later, the star will appear to have moved slightly because it is being viewed from a different point in our planet's orbit around the sun. Knowing the dimensions of Earth's orbit, astronomers can calculate the star's distance from the amount of its apparent movement.

But at the moment, Lucas and his colleagues don't have good enough parallax measurements to be sure of the brown dwarf's precise distance and could be a light year or so out. In just a few weeks, however, new parallax observations should pin the distance down.

If the current distance estimate is right, the brown dwarf is closer than any other known. The previous record-holder is a pair of brown dwarfs around the star Epsilon Indi, 11.8 light years from Earth.

Record breaker

The new brown dwarf breaks two other records as well. It's the coldest brown dwarf ever seen, with a temperature of just 130 to 230 °C. And it's the dimmest: it emits only 0.000026 per cent as much energy as our sun, and this energy emerges at infrared rather than visible wavelengths. It would take 3.8 million of these brown dwarfs to equal the sun's power. It is about the size of Jupiter, but its mass is 5 to 30 times greater.

The object's feeble nature explains why it has only now been spotted, despite its proximity. It was found after surveying only a few per cent of the sky, which implies that many more brown dwarfs are lurking nearby undetected.

Journal reference: arxiv.org/abs/1004.0317
"Giving birth and nourishing,
Bearing yet not possessing,
Working yet not taking credit,
Leading yet not dominating,
This is the Primal Virtue."

- Lao Tsu, Tao Te Ching (10)

Offline Ljubica

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Re: \
« Reply #4 on: May 04, 2010, 10:52:15 PM »
I'm worried about the one not seen yet, in our closest vicinity :(
George Gurdjieff: "We must strive for freedom if we strive for self-knowledge."