7% of the exoplanets listed at this table are greater than 10 Jupiter masses. Deuterium burning occurs at 10-12 Jupiter masses and greater, but doesn't help us categorize objects that have burned up their deuterium. 2-3 Jupiter masses might be a good dividing line, as it marks the transition from the object's radius increasing with mass to the radius actually decreasing with mass (which I won't go into as it leads to discussions of things like electron degeneracy pressure). Other definitions of planets and brown dwarfs make a distinction between the method of formation of the object, but this makes the mass much less important than the object's history, which is much harder to deduce. For instance, Jupiter was long regarded as having formed from runaway accretion starting with a small rocky core, but recent computer models suggest it (and the other gas giants) formed directly from gravitational collapse, just like a star. Also consider the 55-78 Jupiter mass object found orbiting at a distance roughly equivalent to Saturn's orbit around a sun-like star, a distance much too close for many astronomers' comfort.
UKIRT has had a series of upgrades starting in about 1990, including several generations of IR imagers, the addition of active optics, etc.. Thus the modern version of UKIRT is not 23 years old. Nor is 23 years particularly old compared to the ~400 years that telescopic observations have been made.
If you read the fine print, you'll note that it took collaborative observations by 5 different telescopes to merely confirm that brown dwarfs vary in brightness (differently at different colors). While it might confirm they have weather, it certainly does not "determine what kind of weather patterns their atmospheres have."
A confirmed observation of a brown dwarf was not made until 1995 (reference).
Some back-of-the-envelope calculations using some crude rules-of-thumb:
Stars roughly follow a mass-luminosity relationship. L / Lsun=(M / Msun)^2.3 (for M.5*Msun). An estimate for this object indicates it should be.0007 times as luminous as the sun. Actually, due to the lack of fusion, it is only.00002 times as bright.
Also, from Wien's displacement law (lamda_max*T =.290 cm K) and the object's estimated surface temperature of 1273 K, it's peak radiation occurs at a wavelength of 2280 nm, far into the infrared.
The bulk of what little light brown dwarves emit is emitted in the infrared, making them practically invisible without a very expensive (and new) telescope. This has led to speculation that an unnoticed brown dwarf (the infamous Nemesis) could be orbiting our own sun!
The Rosetta launch would have required the rocket to enter Earth orbit and then re-fire (a.k.a. a ballistic coast phase). This would have been the first time this maneuver was attempted with an Ariane 5. This particular Ariane 5 also had significant changes made to its equipment bay and electrical system.
(paraphrasing from this linkand other sources)
The article is not about quasars. Quasars are sisters of a group of objects known as QSOs. QSOs and quasars are bright across 15 orders of magnitude of the light energy spectrum, but quasars are radio-bright and QSOs are not. There was no mention in the article of radio studies being performed in concert with the visible and infrared observations, so these objects are QSOs until further notice. And since the galaxies are only visible because of the stars in them, the article's title is partly correct.
Slashdot Mirror
Or was it a beautifully planned DoS attack using a bunch of unwitting /.ers? If ever there was a website deserving a DoS, this was it.
A stellar idea.
7% of the exoplanets listed at this table are greater than 10 Jupiter masses. Deuterium burning occurs at 10-12 Jupiter masses and greater, but doesn't help us categorize objects that have burned up their deuterium. 2-3 Jupiter masses might be a good dividing line, as it marks the transition from the object's radius increasing with mass to the radius actually decreasing with mass (which I won't go into as it leads to discussions of things like electron degeneracy pressure). Other definitions of planets and brown dwarfs make a distinction between the method of formation of the object, but this makes the mass much less important than the object's history, which is much harder to deduce. For instance, Jupiter was long regarded as having formed from runaway accretion starting with a small rocky core, but recent computer models suggest it (and the other gas giants) formed directly from gravitational collapse, just like a star. Also consider the 55-78 Jupiter mass object found orbiting at a distance roughly equivalent to Saturn's orbit around a sun-like star, a distance much too close for many astronomers' comfort.
UKIRT has had a series of upgrades starting in about 1990, including several generations of IR imagers, the addition of active optics, etc.. Thus the modern version of UKIRT is not 23 years old. Nor is 23 years particularly old compared to the ~400 years that telescopic observations have been made. If you read the fine print, you'll note that it took collaborative observations by 5 different telescopes to merely confirm that brown dwarfs vary in brightness (differently at different colors). While it might confirm they have weather, it certainly does not "determine what kind of weather patterns their atmospheres have." A confirmed observation of a brown dwarf was not made until 1995 (reference).
Or wear an aluminum foil hat!
Jupiter and Saturn could be considered brown dwarfs. They might actually prove to be crucial for the formation of terrestrial planets.
Some back-of-the-envelope calculations using some crude rules-of-thumb: Stars roughly follow a mass-luminosity relationship. L / Lsun=(M / Msun)^2.3 (for M.5*Msun). An estimate for this object indicates it should be .0007 times as luminous as the sun. Actually, due to the lack of fusion, it is only .00002 times as bright.
Also, from Wien's displacement law (lamda_max*T = .290 cm K) and the object's estimated surface temperature of 1273 K, it's peak radiation occurs at a wavelength of 2280 nm, far into the infrared.
The bulk of what little light brown dwarves emit is emitted in the infrared, making them practically invisible without a very expensive (and new) telescope. This has led to speculation that an unnoticed brown dwarf (the infamous Nemesis) could be orbiting our own sun!
The Rosetta launch would have required the rocket to enter Earth orbit and then re-fire (a.k.a. a ballistic coast phase). This would have been the first time this maneuver was attempted with an Ariane 5. This particular Ariane 5 also had significant changes made to its equipment bay and electrical system. (paraphrasing from this linkand other sources)
No, poyethylene glycol is not antifreeze. Ethylene glycol is. Do not put plastic in your radiator.
The article is not about quasars. Quasars are sisters of a group of objects known as QSOs. QSOs and quasars are bright across 15 orders of magnitude of the light energy spectrum, but quasars are radio-bright and QSOs are not. There was no mention in the article of radio studies being performed in concert with the visible and infrared observations, so these objects are QSOs until further notice. And since the galaxies are only visible because of the stars in them, the article's title is partly correct.