Exoplanetary Science

Thoughts on Kepler 62 and Habitability

April 22, 2013

Because we only have direct images of a tiny number of planets orbiting other stars, we’re used to extrapolating as much as we can from our data and plugging in possible scenarios. But as the recent announcement of two ‘super-Earths’ around Kepler 62 demonstrates, we’re coming up hard against the limits of our knowledge. The [...]

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Water Worlds in the Habitable Zone

April 18, 2013

“The fault, dear Brutus, is not in our stars, But in ourselves, that we are underlings.” Thus Cassius speaking to Brutus in Shakespeare’s Julius Caesar, trying to convince him that what happens to us comes not from some malign fate but from our own actions. I’m sure he’s right, too, but I admit there are [...]

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The Era of Planet Gathering

April 11, 2013

We’ve looked at a couple of exoplanet issues this week that bear further comment. The first is that different detection methods can be usefully combined to cover different scenarios. If radial velocity works best with larger planets closer to their star, direct imaging takes us deep into the outer planetary system. We saw yesterday how [...]

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Planetary Systems Around Subgiant Stars

April 10, 2013

Our exoplanet detection methods have their limits. Radial velocity studies work great in the inner regions of planetary systems, but become more challenging as we move away from the star. Direct imaging is the reverse — we’re most likely to see a distant planet if it’s both large and well separated from the primary. Clearly [...]

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TESS: A Full-Sky Exoplanet Survey

April 8, 2013

The news that NASA has approved the TESS mission kept my mood elevated all weekend. TESS (Transiting Exoplanet Survey Satellite) has been the logical NASA follow-up to Kepler ever since the Space Interferometry Mission was canceled in 2010. The point is that Kepler looks at a field of stars with the goal of developing a [...]

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Toward a Census of Earth-Sized Worlds

April 5, 2013

While transit and radial velocity methods get most of the press when it comes to finding exoplanets, gravitational microlensing offers an independent alternative. Here a star passes in front of a far more distant object, causing the light from the source to be gravitationally ‘bent’ by the intervening star. The useful thing for exoplanet work [...]

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Habitable Zone Planets: Upping the Numbers

March 14, 2013

Whether we’re planning to go to the stars on a worldship or with faster transportation, the choice of targets is still evolving, and will be for some time. Indeed, events are moving almost faster than I can keep up with them. It was in early February that Courtney Dressing and David Charbonneau (Harvard-Smithsonian Center for [...]

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Stranger Than Fiction

March 8, 2013

Just what does it take to make a habitable world? Keith Cooper is editor of Astronomy Now, the British monthly whose first editor was the fabled Patrick Moore. An accomplished writer on astronautics and astronomy as well as a Centauri Dreams regular, Keith has recently become editor of Principium, the newsletter of the Institute for [...]

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Life Around Dying Stars

February 26, 2013

Where is the best place to look for life? At first glance, a red dwarf would seem to be the ideal choice because a transiting terrestrial-class world in the habitable zone of a red dwarf is going to block a larger part of the star’s light than a similarly sized world orbiting a larger star. [...]

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Small Planets Confirm Kepler’s Capabilities

February 21, 2013

The planetary system around Kepler-37, some 210 light years from Earth in the constellation Lyra, had its place in the media spotlight yesterday, although it will surely be a brief one. But it’s heartening to see the quickening interest in exoplanets that each new discovery brings. Will the interest continue? In the Apollo days, public [...]

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