Exoplanetary Science

Red Dwarfs: Oldest Known Circumstellar Disk

October 24, 2016

Determining the age of a star is not easy, but one way of proceeding with at least some degree of confidence is to identify the star as a member of a stellar association. Here we’re talking about a loose cluster of stars of a common origin. Over time, the stars have begun to separate, but […]

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Detecting Long-Period Planets & Stellar Companions

October 6, 2016

Spotting planets a long way from their stars is no easy proposition when you’re using radial velocity methods. The idea is to track the minute movement of the star as it is affected by an orbiting planet, which shows up as a Doppler shift in the data. What we’re actually seeing is the star and […]

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System Evolution: Delving into Brown Dwarf Disks

October 4, 2016

We’ve seen circumstellar disks around numerous stars, significant because it is from such disks that planets are formed, and we would like to know a good deal more about how this process works. Now we have word of planet-forming disks around several low-mass objects that fit into the brown dwarf range, and one small star […]

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Circumbinary Planet Found in Microlensing Data

September 23, 2016

A circumbinary planet is one that orbits two stars, and to date we haven’t found many of them. Word of a new detection comes from an event observed back in 2007 during a microlensing study called OGLE — Optical Gravitational Lensing Experiment. OGLE is a Polish undertaking designed to study dark matter using gravitational microlensing, […]

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Stormy ‘Space Weather’ for M-dwarf Planets?

September 22, 2016

Proxima Centauri b, that highly interesting world around the nearest star, is about 0.05 AU out from its primary. The figure leaps out to anyone new to red dwarf stars, because it’s so very close to the star itself, well within the orbit of Mercury in our own system. But these are small, dim stars […]

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A Strong Case for TRAPPIST-1 Planets

September 13, 2016

TRAPPIST continues to be my favorite astrophysical acronym. Standing for Transiting Planets and Planetesimals Small Telescope, the acronym flags a robotic instrument at the La Silla Observatory in Chile that is operated by the the Institut d’Astrophysique et Géophysique (University of Liège, Belgium) in cooperation with the Geneva Observatory. The name is a nod to […]

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On Planets in Binary Systems

September 12, 2016

Alpha Centauri A and B, the two primary stars of the Alpha Centauri threesome, orbit a common center of gravity, with an average separation of 23.7 AU. But bear in mind that this average covers wider ground. The separation can close to about 11 AU or widen to as far as 36 AU. I bring […]

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Proxima b: Obstacles and Opportunities

September 1, 2016

Meeting people I’ve written about is always a pleasure at gatherings of the interstellar-minded, and I was delighted to run into Victoria Meadows (University of Washington) in the lobby of our hotel on the final day of the Breakthrough Starshot meetings. Rory Barnes is a colleague of Meadows at UW and recently described the research […]

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A Closer Look at Proxima b

August 31, 2016

I have much more to say about the Breakthrough Starshot meetings, but last evening I decided to slow the pace a bit. I mentioned in my first report that the discovery of a planet around Proxima Centauri had woven through our San Francisco meetings, creating a bright thread of discussion that continued through all three […]

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Proxima Centauri Planet

August 24, 2016

A planet in the habitable zone around Proxima Centauri? The prospect dazzles the imagination, but then, I’ve been thinking about just that kind of planet for most of my life. Proxima Centauri is, after all, the closest star to our own, about 15000 AU from the primary Alpha Centauri stars (though thought to be moving […]

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