Tag: Kepler

Discovered: The First Binary Star System With Multiple Planets

By Sophie Bushwick | August 29, 2012 12:52 pm

Kepler-47
Artist’s rendering of binary system Kepler-47, with outer planet Kepler-47c
in the foreground and inner planet Kepler-47b in the bottom right corner

Growing up in a binary star system can be tough. As the system’s two suns orbit each other, they exert strong gravitational pressures capable of pushing away young planets or sending them careening into one another. It wasn’t until last year that astronomers found the first evidence of a world orbiting two stars. Now new data has revealed that the binary system Kepler-47 goes one step further: it contains not one but two planets.

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CATEGORIZED UNDER: Space

In the Milky Way, There Are As Many Planets As Stars

By Veronique Greenwood | January 12, 2012 12:49 pm

planets

There are at least as many planets in the galaxy as there are stars. And even that is probably a vast underestimate.

That’s the latest bombshell from astronomers looking for planets beyond our solar system. Phil Plait at Bad Astronomy will have a post on this soon, but for now, here’s a little quote salad for you:

“Planets are like bunnies; you don’t just get one, you get a bunch,” said Seth Shostak, a senior astronomer at the SETI Institute who was not involved in this research. “So really, the number of planets in the Milky Way is probably like five or 10 times the number of stars. That’s something like a trillion planets.” (via PopSci)

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CATEGORIZED UNDER: Space

Exoplanet Reflects Practically No Light—and Scientists Have No Idea Why

By Joseph Castro | August 12, 2011 3:16 pm

spacing is important

What’s the News: Using data from NASA’s Kepler spacecraft, astronomers from Princeton University and the Harvard-Smithsonian Center for Astrophysics have discovered the darkest known planet. The exoplanet, called TrES-2b, is located about 750 light-years away from Earth and reflects less than 1 percent of the incident light from its parent star, making it blacker than the blackest piece of coal. The discovery was published recently in the Monthly Notices of the Royal Astronomical Society (pdf).

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CATEGORIZED UNDER: Space

From White Dwarfs to Dark Matter Clouds, the Universe May Have Many Homes for Habitable Planets

By Patrick Morgan | March 31, 2011 3:06 pm

What’s the News: While the Kepler spacecraft is busy finding solar system-loads of new planets, other astronomers are expanding our idea where planets could potentially be found. One astronomer wants to look for habitable planets around white dwarfs, arguing that any water-bearing exoplanets orbiting these tiny, dim stars would be much easier to find than those around main-sequence stars like our Sun. Another team dispenses with stars altogether and speculates that dark matter explosions inside a planet could hypothetically make it warm enough to be habitable, even without a star. “This is a fascinating, and highly original idea,” MIT exoplanet expert Sara Seager told Wired, referring to the dark matter hypothesis. “Original ideas are becoming more and more rare in exoplanet theory.”

How the Heck:

  • Because white dwarfs are much smaller than our Sun, an Earth-sized planet that crossed in front of it would block more of its light, which should make these planets easier to spot. So astronomer Eric Agol suggests survey the 20,000 white dwarfs closest to Earth with relatively meager 1-meter ground telescopes.
  • And because white dwarfs are so cool, a planet in a white dwarfs habitable zone would be very close, meaning its transit would happen very fast. Agol says we’d only need to watch a star for 32 hours to pick up on any transiting, habitable planets.
  • One leading theory about dark matter is that it’s made of theoretical particles called WIMPS (weakly interacting massive particles). It’s thought that when WIMPs collide (if, of course, they exist), they would explode. Astronomers think that these WIMP explosions could possibly heat a planet enough to make it habitable.
  • There are no immediate plans to test the dark matter hypothesis, which is quite theoretical, and any plan to find dark matter-fueled planets would need to look far from here: our part of the universe doesn’t have nearly enough dark matter to bring a planet to habitability.

What’s the Context:

Not So Fast:

  • It’s not at all clear if white dwarfs have any planets, and if so, whether any of them could possibly support water or life as we know it. For one thing, planets in the habitable zone would be tidally locked with the star—permanent scalding daylight on one side; permanent frozen nighttime on the other.
  • Taking 32 hours to find a planet orbiting a white dwarf may seem like a short time, but when you’re looking at tens of thousands of stars, it adds up. Agol told UW Today, “This could take a huge amount of time, even with [a network of telescopes].”
  • And just like star-orbiting planets have their Goldilocks zones (not to hot or too cold), dark matter-containing planets would need the right amount of dark matter to be habitable. “It’s not something that’s likely to produce a lot of habitable planets,” Fermilab researcher Dan Hooper told Wired. “But in very special places and in very special models, it could do the trick.” 

References: Eric Agol. “TRANSIT SURVEYS FOR EARTHS IN THE HABITABLE ZONES OF WHITE DWARFS.” doi: 10.1088/2041-8205/731/2/L31

Dan Hooper and Jason H. Steffen. “Dark Matter And The Habitability of Planets.” arXiv:1103.5086v1

Image: NASA/European Space Agency

CATEGORIZED UNDER: Space, Top Posts

Astronomers Say Milky Way Has Around 2 Billion “Earth Analog” Planets (That’s the Bad News)

By Patrick Morgan | March 30, 2011 1:35 pm

What’s the News: Based on early Kepler data, astronomers say that the Milky Way galaxy may house at least two billion Earth-like planets—one for every several dozen sun-like stars. As NASA researcher Joseph Catanzarite told Space.com, “With that large a number, there’s a good chance life and maybe even intelligent life might exist on some of those planets. And that’s just our galaxy alone — there are 50 billion other galaxies.” But while 2 billion sounds like a lot, it’s actually far below many scientists’ expectation; Catanzarite says his teams’ findings actually show that Earth-like planets are “relatively scarce.”

How the Heck:

  • Using mathematical models to plot the size and orbital distance for all the potential planets spotted during four months’ worth of Kepler data, astronomers extrapolated the data and calculated that 1.4 to 2.7% of the Milky Way’s sun-like stars may have an Earth analog.
  • Two percent of the Milky Way’s roughly one hundred billion sun-like stars means that “you have two billion Earth analog planets in the galaxy,” Catanzarite told National Geographic.

What’s the Context:

Not So Fast:

  • MIT astronomer Sara Seager says that the team “completely underestimates the frequency of Earths.” The calculations are based on only four months of Kepler data—too early to be making an accurate projection.
  • There’s also the fact that Kepler can only detect the size and orbital distance (and occasionally the masses) of planets, which doesn’t tell you whether life as we know it could actually live there; Venus, for example, would roughly like Earth to aliens peering at us from many light-years away, but because of its atmosphere’s runaway greenhouse effect, it’s way too hot to be habitable.

Next Up: The astronomers plan on calculating an even more accurate number once all of Kepler’s data is in.

Reference: Joseph Catanzarite and Michael Shao. “The Occurrence Rate of Earth Analog Planets Orbiting Sunlike Stars.” arXiv:1103.1443v1 Image: Kepler/NASA

CATEGORIZED UNDER: Space

Exclusive: "Most Earth-Like" Exoplanet Gets Major Demotion—It Isn't Habitable

By Andrew Grant | March 8, 2011 10:13 am

Last month, when astronomers with the Kepler space telescope released a list of 1,235 possible planets orbiting other stars, one particular candidate, KOI 326.01, especially stood out. Scientists, journalists, and the general public couldn’t help it: In a population of planetary candidates dominated by sizzling, Jupiter-sized gas giants—which are much easier to spot—here was the closest thing yet to our very own planet. It was just about the size of Earth, even a little smaller, and had a temperature around 138 degrees—rather warm for human tastes, but still a place where liquid water could rain down from clouds into oceans, and where life as we know it could possibly exist. A clever but perhaps overambitious monetary calculation valued the planet at exactly $223,099.93.

Alas, KOI 326.01’s 15 minutes of fame must now end. Additional analysis of the planet’s star now suggests that the planet is a lot larger, and most likely a lot hotter, than previously thought. “The details of the planet need to be hammered out, but this certainly means that this is not an Earth-size planet in the habitable zone,” where liquid water could exist, says Natalie Batalha, a Kepler team member.

The road to demotion began when a DISCOVER fact-checker, Mara Grunbaum, asked for some additional information about the planet. In response, Batalha and her colleagues dug up images of the sky near KOI 326.01—and almost immediately found a problem. The planet’s sun, known as KIC 9880467, is located close to another star (see above). In a reference catalog characterizing the stars in the probe’s field of view, KIC 9880467 is listed as brighter than its neighbor. But as you can easily see in the above image, that is not the case.

That simple error messes up the calculations of the planet’s temperature and size. Kepler finds planets by detecting tiny dips in a star’s brightness during transits—when a planet crosses in front of it. When the Kepler team analyzed the combined light from the two stars, they assumed KIC 9880467 accounted for most of the brightness. Now they have to chalk up almost all that light to the neighboring star. In fact, while Batalha is still confident KOI 326.01 exists, she is no longer sure which of the two nearby stars it is orbiting. In either case, the calculations indicate that the planet is somewhat warmer and a lot larger than the previous estimate. And if it is orbiting the bright, neighboring star, as Batalha suspects, the planet’s temperature will soar. More analysis is required, but it’s safe to say that KOI 326.01 should no longer be considered potentially habitable.

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CATEGORIZED UNDER: Space, Top Posts

Our Galaxy May Have 50 Billion Exoplanets–and It's Still Making More

By Andrew Moseman | February 25, 2011 1:27 pm


Young. Old. Scalding hot. Icy cold. Terrestrial midgets. Gas giants. As the cavalcade of planets spotted beyond our solar system continues to grow, we get to see worlds of all sorts—and we get to speculate on the staggering number of exoplanets that might inhabit just our own galaxy.

Today’s first piece of otherworldly news involves baby exoplanets. Astronomer Christian Thalmann says his team may have spotted planets in the process of forming around three different stars, the first time scientists have spotted the process in action.

An infant star forms from a collapsing cloud of dust and gas and gathers a dense, flat disk of material that rotates with the star like a record album. The material in the disk will eventually clump up into nascent planets. Theoretical models of planet formation predicted that those protoplanets should suck up more gas and dust with their gravity, clearing a wide gap in the otherwise solid disk. [Wired]

Peering at young stars like T Chamaeleontis (T Cha) LkCa15 and AB Auriga, Thalmann and colleagues saw those telltale gaps in the dusty rings (their study is forthcoming in the Astrophysical Journal Letters). The stars are much like our own sun, so these pictures of infant solar systems could resemble what our own looked like as a baby. But though the stars are nearby in cosmic terms—T Cha lies just 350 light years away—the gaps are faint enough that it’s difficult to tell for certain if newly forming planets, and not the influence of binary stars or other objects, are creating them.

If Thalmann’s team is right, catching the birth of new worlds would be a great scientific coup. Our galaxy, however, isn’t exactly hurting for planets.

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CATEGORIZED UNDER: Space

Kepler's Plenty: 6 Super-Earths, And 1,200 More Exoplanet Candidates

By Andrew Moseman | February 2, 2011 4:02 pm

For months we here at DISCOVER have been waiting impatiently for the Kepler mission to open up its vault of new exoplanets, hopefully filled with a bevy of Earth-like worlds and other exotic planets. Today planet lovers got a new peek at the Kepler findings, and those findings are stunning.

First, the Kepler scientists announced more than 1,200 candidate planets, which got DISCOVER blogger Phil Plait excited:

This is incredible! Even though I was expecting a number like this, actually hearing it for real is stunning. In 15 years we’ve found about 500 planets orbiting other stars, but in the almost two years since Kepler launched it may have easily tripled that number! Now, to be careful: these are candidate planets, which means they have not been confirmed. But in most cases these look pretty good, and if these numbers hold up it indicates that our galaxy is lousy with planets. They’re everywhere.

While those 1,200 are candidates, astronomers have confirmed a peculiar and fascinating set of six. From Phil Plait:

Using NASA’s orbiting Kepler observatory, astronomers have found a complete solar system of six planets orbiting a sun-like star… and it’s really weird: five of the six planets huddle closer to their star than Mercury does to the Sun!

None of them is what I would call precisely earth-like — they’re all more massive and much hotter than Earth — but their properties are intriguing, and promise that more wonderful discoveries from Kepler are coming.

Related Content:
80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
80beats: How Excited Should We Be About the New “Goldilocks” Exoplanet?
80beats: Astronomers Find a Bevy of Exoplanets; Won’t Discuss Most Interesting Ones
DISCOVER: How Long Until We Find a Second Earth?

ESO/L. Calçada

CATEGORIZED UNDER: Space
MORE ABOUT: exoplanets, Kepler, NASA, stars

Kepler Finds a Super-Small, Super-Hot Rocky Exoplanet

By Eliza Strickland | January 10, 2011 2:46 pm

The Kepler space telescope, launched nearly two years ago, has already proven its worth as an exoplanet hunter many times over. But the discoveries keep on coming. NASA just announced that Kepler has found its first rocky planet–and that the rocky world is only 1.4 times the size of Earth, making it the smallest exoplanet ever found.

Phil Plait explains that this nearly Earth-sized isn’t actually Earth-like and habitable:

[I]t orbits extremely close in to its star, circling over the star’s surface at a distance of roughly 3 million kilometers (1.8 million miles) — amazingly, it takes less than an Earth day to make one circuit. But being that close to a star comes at a price: the surface temperature of the planet must be several thousand degrees!

The planet, Kepler-10b, may not be habitable to life as we know it, but Plait is still plenty excited. Get the rest of the story on how the planet was found and what its discovery means over at Bad Astronomy.

Related Content:
80beats: Astronomers Predict a Bonanza of Earth-Sized Exoplanets
80beats: How Excited Should We Be About the New “Goldilocks” Exoplanet?
80beats: Astronomers Find a Bevy of Exoplanets; Won’t Discuss Most Interesting Ones
80beats: After a Flawless Launch, Kepler Telescope Gets Ready for Planet Hunting
DISCOVER: How Long Until We Find a Second Earth?

CATEGORIZED UNDER: Space

Astronomers Predict a Bonanza of Earth-Sized Exoplanets

By Andrew Moseman | October 28, 2010 4:04 pm

keckThe universe abounds with Earth-sized planets. That hopeful notion has been reinforced by individual planets finds like possible Goldilocks planet Gliese 581g, by the hordes of planet candidates discovered by the Kepler mission, and now, by a census of a small space in the sky that tells us one in four sun-like stars should possess worlds that are close to the size of Earth.

Take a moment to think about that: One in four.

In Science, exoplanet hunters Geoffrey Marcy and Andrew Howard published their team’s census of 166 nearby stars like ours, of which they picked 22 at random to investigate for planets. They watched the stars’ doppler shifts to hunt for planets over the last five years, and used the results to extrapolate how common terrestrial planets must be far beyond just this set of stars.

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CATEGORIZED UNDER: Space, Top Posts
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