First Images of Brown Dwarf in a Planetary System

[yevaud]

<b>Scientists using NASA's Spitzer Space Telescope have discovered and directly imaged a small brown dwarf star, 50 times the mass of Jupiter, orbiting with a planet around a Sun-like star. Such an arrangement has never before been seen but might be common, the scientists say, leading to solar systems with distorted planetary orbits.<br /></b><br /><br />Kevin Luhman of Penn State University is the lead author on a report describing this discovery, which will be published in The Astrophysical Journal. The discovery concerns a class of the coldest brown dwarfs, called T dwarfs.<br /><br />"Over the last ten years, astronomers have been extremely successful in finding planets close to their host stars using indirect detection methods," said Luhman, an assistant professor in the Penn State Department of Astronomy and Astrophysics. "Because of its infrared capabilities, Spitzer is well suited for directly detecting cool T dwarfs, and perhaps even large planets, in the outer parts of planetary systems."<br /><br />Luhman's team also discovered a second brown dwarf that is smaller yet, about 20 times the mass of Jupiter, orbiting another star. This smaller object could be the youngest T dwarf known, offering scientists a snapshot of early brown-dwarf development. The two T dwarfs are the first to be imaged by Spitzer. Shortly after these companions were found, Spitzer also discovered a T dwarf that is floating through space by itelf rather than orbiting a star. The team that discovered that T dwarf is led by Daniel Stern at NASA's Jet Propulsion Laboratory.<br /><br />[Scientists snap first images of brown dwarf in planetary system]<br /><br />This is an artist's concept of the star HD 3651 as it is orbited by a close-in Saturn-mass planetary companion and the distant brown dwarf companion discovered by Spitzer infrared photographs. The Saturn-mass planet was discovered through Doppler observations in 2003. Its orbit is very small, the size of Mercury's, and is highly elliptical. Th <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[jmilsom]

Excellent article. I imagine we are going to find every possible gradation between gas giant and star and it may be hard to draw the line between the two in the end. When does a gas giant become a cold brown dwarf? <div class="Discussion_UserSignature"> </div>

 

[qso1]

Yep, the IAU will have its work cut out for it when they are tasked with determining when a planet is referred to as a star. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[derekmcd]

The debates will be enjoyable. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[qso1]

Thats for sure. I'm looking forward to the day when these debates will be underway. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[colesakick]

I’ve read journal articles that state that most star systems exist in tandem with other stars to the extent that lone star systems are in fact the exception, not the rule. It is said that the odds of our star being alone are quite small, given the nature of star systems on average. There is a thoughtful website that considers the precession of the equinoxes in the context of our sun having a brown dwarf companion. Take a gander<br /><br />http://www.binaryresearchinstitute.com <br /> <div class="Discussion_UserSignature"> Intellectual honesty means being willing to challenge yourself instead of others </div>

 

[alokmohan]

September 21, 2006<br />Scientists using NASA's Spitzer Space Telescope have imaged a brown dwarf star about 50 times Jupiter's mass, orbiting a Sun-like star with a planet. Never before have astronomers witnessed a union like this.<br /><br />Brown dwarf HD 3651 B, located in the constellation Pisces, is classified as a T dwarf — the coldest brown dwarfs. The star in the system is less massive than our Sun, and the planet is slightly larger than Saturn. The team, whose paper will appear in The Astrophysical Journal, discovered HD 3651 B by measuring the planet's highly elliptical orbit in this system. They suspected an undiscovered object's gravity influences the planet's orbit. Spitzer confirmed these suspicions by revealing the brown dwarf.<br /><br />"The orbit of the planet in this system is similar to Mercury's, but the T dwarf has an orbit over 10 times larger than Pluto's," says Brian Patten of the Harvard-Smithsonian Center for Astrophysics and co-author of the team's paper. "Although HD 3651 B would be just beyond naked-eye visibility to an intrepid astronomer living on this system's planet, the T dwarf makes its presence known through gravity."<br /><br />Confirmed in 1995, brown dwarfs are dim, small stars that are not massive enough to burn hydrogen or hot enough to generate nuclear fusion. As these bodies age, they cool to nearly the temperature of a planet.<br /><br />"Over the last 10 years, astronomers have been extremely successful in finding planets close to their host stars using indirect detection methods," says Penn State's Kevin Luhman, lead author of the team's paper. "Because of its infrared capabilities, Spitzer is well suited for directly detecting cool T dwarfs, and perhaps even large planets, in the outer parts of planetary systems."<br /><br />Luhman's team also found a smaller brown dwarf, about 20 times the mass of Jupiter, orbiting another star. Labeled HN Peg B, this smaller object could be the youngest T dwarf known Courtesy: astronomy journa