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The Countdown, Episode 18 – Exoplanet Composition, Neighborhood Dwarfs, Comet Pan-STARRS, Martian Love Boat, the Methuselah Star

The views expressed are those of the author and are not necessarily those of Scientific American.


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[The text below is a modified transcript of this video.]

5) Exoplanet Composition

Scientists have determined the chemical composition of an exoplanet’s atmosphere–129 light years away. The planet is a gas giant five to ten times more massive than Jupiter and it lives in a solar system along with four other gassy planets.

Using data from Hawaii’s Keck telescope, scientists have determined the planet’s atmosphere is made up mostly of water vapor and carbon monoxide. They were able to figure this out by directly analyzing light from the planet. Usually, information about exoplanets is obtained indirectly, by measuring their effect on the orbit of the parent star. But HR8799c circles its sun at about the same distance as Pluto orbits our sun. This allowed scientists to isolate its light from the background radiation.

The scientists also found the atmosphere contains a slightly higher ratio of carbon to oxygen than its parent star. This tells us the planet likely formed from a ball of ice and dust, which grew slowly, attracting more and more space dust from the embryonic solar system.

You can read more about this fascinating exoplanet in the March 15 issue of the Journal Science.

4) Neighborhood Dwarves

Prepare a house-warming gift and get ready to greet our new neighbors. Penn State University astrophysicist Kevin Luhman has discovered a binary system of two brown dwarfs right next door to our Sun. And by next door, we mean 6.5 light years away.

It sounds like a pretty large separation, but only two known star systems are closer to home, and we found them almost a century ago.

So why did it take us so long to discover this binary system, dubbed WISE 1049-5319? Well, it’s made up of very dim objects. Brown dwarfs are bigger than planets but smaller than stars, and they emit so little light that our telescopes have trouble picking them out.

But they couldn’t hide from the Wide-Field Infrared Survey Explorer, or WISE for short. Given how long it took us to find them, we could have more brown dwarfs right under our noses. Our neighborhood might be more heavily populated than we ever expected.

You can find out more about the brown dwarf binary system in Astrophysical Journal Letters.

3) Comet Pan-STARRS

Last week the comet Pan-STARRS dipped within the orbit of mercury, making its tail visible in the night sky. Although, its light is already dimming, you might still be able to see it faintly until the end of March. But if you missed out altogether, no need to worry. In November, we can expect an even larger, brighter comet named ISON. Astronomers are calling it “the comet of the century” and think it could shine even brighter than the moon.

2) Martian Love Boat

Sure, Niagara Falls is a classic honeymoon destination. But if you really want to sweep a girl off her feet, why not carry her all the way to Mars? Multimillionaire Dennis Tito founded a non-profit foundation, with the goal of shipping a married couple to the red planet and back.

According to the plan, the couple will launch in a Space X Dragon capsule in January 2018. With a boost from the sun’s gravity, the astronauts should reach Mars by August, orbit the planet, and then return to Earth after 501 days. This is the longest continuous period any human has spent in space, and it will expose the travelers to a lot of solar radiation. Which unfortunately increases their odds of developing cancer. But Tito’s team plans to protect the couple with a radiation shield constructed from easily available materials. Namely, the astronauts’ poop.

Cancer and poop shields won’t be the only obstacles this lucky couple faces. They’ll also have to deal with each other. For one and a third years, the astronauts must live in a cramped inflatable habitat docked to the Dragon capsule–a habitat of only 17 cubic meters. Good thing Tito’s team is pre-screening applicants—they’ll need to really love each other.

1) The Methuselah Star

The oldest known star isn’t quite as old as we thought. But that’s okay—previous estimates suggested it was older than the universe itself.

For years, the star HD 140283 has been baffling astronomers. Up until 2000, observations suggested the so-called Methuselah star was 16 billion years old. Which is a serious problem when you consider our universe is only 13.8 billion years old. To get a better estimate of Methuselah’s age, researchers needed better data. So they used the Hubble Space Telescope to make a more accurate measurement of the star’s distance from Earth. With this information, and modern theories about chemical makeup and burn rate, the scientists came up with an age estimate five times more accurate than previous attempts.

They now think the Methuselah star is 14.5 billion years old, plus or minus 0.8 billion years. This is still ridiculously old, but the uncertainty means Methuselah could be as young as 13.7 billion years, which would make it younger than the universe—just barely.

To learn more about the Methuselah star, check out the study in Astrophysical Journal Letters.

—Portions of the script above written by Sophie Bushwick & Eric R. Olson

About the Author: Eric is multimedia journalist and producer who specializes in science and natural history. His work has appeared on the websites of Scientific American, Nature, Nature Medicine, Popular Science, Slate and The New York Times among many others. He is a former video producer & editor for Scientific American. Follow on Twitter @EricROlson.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Steve926 6:56 am 03/24/2013

    Does the recalculation of the Methusela Star’s age mean a recalculation is required for all the stars or just this one in particular?

    Link to this

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