Alien world is blacker than coal

Aug 11, 2011
The distant exoplanet TrES-2b, shown here in an artist's conception, is darker than the blackest coal. This Jupiter-sized world reflects less than one percent of the light that falls on it, making it blacker than any planet or moon in our solar system. Astronomers aren't sure what vapors in the planet's superheated atmosphere cloak it so effectively. Credit: David A. Aguilar (CfA)

(PhysOrg.com) -- Astronomers have discovered the darkest known exoplanet - a distant, Jupiter-sized gas giant known as TrES-2b. Their measurements show that TrES-2b reflects less than one percent of the sunlight falling on it, making it blacker than coal or any planet or moon in our solar system.

"TrES-2b is considerably less reflective than black acrylic paint, so it's truly an alien world," said astronomer David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA), lead author on the paper reporting the research.

In our , Jupiter is swathed in bright clouds of that reflect more than a third of the reaching it. In contrast, TrES-2b (which was discovered in 2006 by the Trans-Atlantic Exoplanet Survey, or TrES) lacks reflective clouds due to its high temperature.

TrES-2b orbits its star at a distance of only three million miles. The star's intense light heats TrES-2b to a temperature of more than 1,800° Fahrenheit - much too hot for ammonia clouds. Instead, its exotic atmosphere contains light-absorbing chemicals like vaporized sodium and potassium, or gaseous titanium oxide. Yet none of these chemicals fully explain the extreme blackness of TrES-2b.

"It's not clear what is responsible for making this planet so extraordinarily dark," stated co-author David Spiegel of Princeton University. "However, it's not completely pitch black. It's so hot that it emits a faint red glow, much like a burning ember or the coils on an electric stove."

Kipping and Spiegel determined the reflectivity of TrES-2b using data from NASA's Kepler spacecraft. Kepler is designed to measure the brightnesses of distant with extreme precision.

The team monitored the brightness of the TrES-2 system as the planet orbited its star. They detected a subtle dimming and brightening due to the planet's changing phase.

TrES-2b is believed to be tidally locked like our moon, so one side of the planet always faces the star. And like our moon, the planet shows changing phases as it orbits its star. This causes the total brightness of the star plus planet to vary slightly.

"By combining the impressive precision from Kepler with observations of over 50 orbits, we detected the smallest-ever change in brightness from an : just 6 parts per million," said Kipping. "In other words, Kepler was able to directly detect visible light coming from the planet itself."

The extremely small fluctuations proved that TrES-2b is incredibly dark. A more reflective world would have shown larger brightness variations as its phase changed.

Kepler has located more than 1,200 planetary candidates in its field of view. Additional analysis will reveal whether any other unusually dark lurk in that data.

TrES-2b orbits the star GSC 03549-02811, which is located about 750 light-years away in the direction of the constellation Draco. (One light-year is about 6 trillion miles.)

Explore further: Image: NGC 6872 in the constellation of Pavo

More information: This research has been accepted for publication in the Monthly Notices of the Royal Astronomical Society and is available online.

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Titto
1 / 5 (14) Aug 11, 2011
Now they start telling us about it since they discovered it back in 1983?
I am smelling something......
Gawad
5 / 5 (7) Aug 11, 2011
Titto, the first extra-solar planets were discovered in 1992.
kantanuuv
4.1 / 5 (15) Aug 11, 2011
@Titto, not only were the first extrasolar planets discovered in 1992, Kepler wasn't launched until 2009, and currently monitors more than 100,000 stars simultaneously. So perhaps the astrophysical world can be forgiven if they didn't notify you of this important discovery sooner.

What you're smelling is your own stupidity. Perhaps you should wander back to the FoxNews web site to share your conspiracy theories.
that_guy
5 / 5 (1) Aug 11, 2011
I wish they would explain why they chose this explanation over other possible explanations. To start off with, while we watch the planet, it is tidally locked, and we would only be able to detect an average of 25-30% of the reflected light (while it is in view) to begin with. Second, this planet is so close to the star, and could very well be within the corona or obscured by it much of the time - therefore, a lot of reflected light from the planet would be absorbed, obscured, and washed out by the coronal emissions.

I'm not saying that they're wrong, but when making such a bold claim, perhaps they should explain how they came to their conclusion over other more immediate explanations.
Techno1
2.6 / 5 (5) Aug 11, 2011
Can't even tell us whether the lakes on Mars come from water or lava, but they want to try to calculate the albedo of a planet 750 light-years away.

Can we really detect 1 / 10^26th of a Watt per meter squared?

That's a zero, followed by a decimal, followed by 25 zeros, followed by a 1.

Because that's about what a change of 1 part per million should be at this distance...
JohnMoser
1 / 5 (7) Aug 11, 2011
Katanuuv, the planet wasn't discovered by Kepler. It was discovered by TrES in 2006. It says that in the ARTICLE. If you don't know how to read perhaps you should wander back to the MSNBC website where your blatherings will be welcome.
krwhite
3.7 / 5 (3) Aug 12, 2011
lol.. One person apparently goes to Fox News, and another goes to MSNBC. At least we've got a balanced audience. Our society is so hostile, even on physics news sites. Disappointing.
Vendicar_Decarian
0.4 / 5 (38) Aug 12, 2011
"I am smelling something......" - Titto

You seem to have soiled your underpants again.

Vendicar_Decarian
0.6 / 5 (40) Aug 12, 2011
"Our society is so hostile, even on physics news sites." - krwhite

Well, the ConservaTards have to blame someone else for their collective 40 year course of treason.

The dishonest garbage coming from Faux news is their primary means of blaming others for the fall of America rather than their own policies.
Vendicar_Decarian
0.2 / 5 (35) Aug 12, 2011
"Can we really detect 1 / 10^26th of a Watt per meter squared?" - Techno1

Starlight intensity isn't measured at the detector in watts per square meter, since it can be detected at the single photon level.

The difference in intensity is stated in the article as 6 parts per million. That is 0.000006

No need to pull this 25 zero's nonsense out of your backside.
Titto
1 / 5 (7) Aug 12, 2011
Titto, the first extra-solar planets were discovered in 1992.

Well......not if you check the washington post of 1983 and the dates when Sedna was discovered?? That is way back my friend!!
kow
3 / 5 (4) Aug 12, 2011
"Morpheus: We don't know who struck first, us or them. But we do know it was us that scorched the sky. At the time, they were dependent on solar power. It was believed they would be unable to survive without an energy source as abundant as the sun."
Let's call it the Matrix planet. :)
Titto
1 / 5 (6) Aug 12, 2011
They knew about Sedna back in 1989 allready???
Vendicar_Decarian
0.2 / 5 (35) Aug 12, 2011
Sedna is a trans-Neptunian object discovered in 2003, which currently lies about three times as far from the Sun as Neptune
ClickHere
4 / 5 (1) Aug 12, 2011
Carry on, just getting some popcorn.
Techno1
1 / 5 (3) Aug 12, 2011
"Can we really detect 1 / 10^26th of a Watt per meter squared?" - Techno1

Starlight intensity isn't measured at the detector in watts per square meter, since it can be detected at the single photon level.

The difference in intensity is stated in the article as 6 parts per million. That is 0.000006

No need to pull this 25 zero's nonsense out of your backside.


the difference in intensity is said to be 6 parts per million...

But from our distance that in watts is a ridiculously tiny number.

just picking numbers:

For example, If you change a trillionth of a watt by 6 parts per million, then the SIZE OF THE CHANGE is 6 quintillionths of a watt.

So yeah, you need some reading comprehension.

The light coming from the star and planet is reduced by 750 light-years squared, in meters.

Then your change would be 6 part per million from that value, which is going to have a shit load of zeros, when you put it in absolute terms of watts instead of relative.
kantanuuv
5 / 5 (5) Aug 12, 2011
@Titto: Do you know what *EXTRA*-solar means? Do you know what a planet is?

Can you apply those two grade-school concepts to Sedna and tell me if it's an extra-solar planet?

Go ahead, I'll wait...
Gawad
5 / 5 (3) Aug 12, 2011
Titto, the first extra-solar planets were discovered in 1992.

Well......not if you check the washington post of 1983 and the dates when Sedna was discovered?? That is way back my friend!!

Where the hell are you getting your BS: 1) Sedna is a Solar dwarf planet. 2) It was discovered in 2003. And that's not so long ago, my friend. Anyone can look this up in 10s flat, so what's your problem? Are you in any way related to Rip Van Winkle? ARE YOU Rip Van Winkle???

You know ...1983 ...2003 ...weird!
Vendicar_Decarian
0.3 / 5 (36) Aug 12, 2011
"But from our distance that in watts is a ridiculously tiny number." - Techno

Photons are remarkably small thingies and that is why marveling over their energy distributed over meters is a dumb thing to do.

kantanuuv
5 / 5 (1) Aug 13, 2011
@JohnMoser: At no point did I write that it was discovered by Kepler.

Perhaps you should take your own advice..read slowly and carefully...then respond.
Twin
1 / 5 (2) Aug 14, 2011
Ref of websites as proof of your targets stupidity seems to me to demonstrate your own.