Exoplanetary Science

Building the Gas Giants

August 20, 2015

Yesterday’s article on supernovae ‘triggers’ for star and planet formation shed some light on how a shock wave moving through a cloud of gas and dust could not only cause the collapse and contraction of a proto-star but also impart angular momentum to an infant solar system. Today’s essay focuses on a somewhat later phase […]

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Kepler-453b: A Hard to Find Transiting Circumbinary Planet

August 10, 2015

With the question of habitable planets on my mind following Andrew LePage’s splendid treatment of Kepler-452b on Friday, I want to turn to the interesting news out of San Diego State, where astronomer William Welsh and colleagues have been analyzing a new transiting circumbinary planet, a find that brings us up to a total of […]

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Is Kepler 452b a Rocky Planet or Not?

August 7, 2015

Where is the dividing line between a large, rocky planet and a ‘mini-Neptune?’ It’s a critical issue, because life is at least possible on one, unlikely on the other. But while we’re getting better at figuring out planetary habitable zones, the question of how large a planet can be and remain ‘terrestrial’ is still unresolved. […]

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A Brown Dwarf ‘Laboratory’ for Planet Formation

August 6, 2015

Detecting planets around brown dwarfs is tricky business, but it’s worth pursuing not only for its own sake but because planetary systems around brown dwarfs can tell us much about planet formation in general. A new paper from Andrzej Udalski (Warsaw University Observatory) and colleagues makes this point while noting four brown dwarf planets we’ve […]

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A ‘Rosetta Stone’ for Super-Earths

August 3, 2015

The discovery and confirmation of the exoplanet HD 219134b give us a useful touchstone relatively close to the Solar System. At 21 light years away in the constellation Cassiopeia, HD 219134b distinguishes itself by being the closest exoplanet to Earth to be detected using the transit method. That’s useful indeed, because we’ll be able to […]

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Earth 2.0: Still Looking

July 23, 2015

I’ve come to dislike the term ‘Earth 2.0.’ It’s not so much the idea of a second Earth as the use of 2.0, which in our technological era invariably recalls software updates. Windows 2.0 was better than Windows 1.0, but Windows 3.0 was the one that really took off — the idea here is that […]

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Detection of Pebbles in a Circumstellar Disk

July 9, 2015

Not long ago we looked at a new paper from Alan Boss that modeled interactions in young protoplanetary disks (A Disruptive Pathway for Planet Formation). The idea here is that as dust grains and larger objects bump into each other on the way to forming planetesimals, a mechanism must exist to keep them from spiraling […]

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Methane Detection as New Horizons Closes

July 1, 2015

As I write, we’re thirteen and a half days out from the Pluto/Charon encounter. New Horizons will make its closest approach to Pluto at 0749 EDT (1149 UTC) on July 14. All of which has had me reading Pluto-related science fiction that I missed along the way, including most recently Wilson Tucker’s “To the Tombaugh […]

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A Disruptive Pathway for Planet Formation

June 30, 2015

Planet formation can be tricky business. Consider that our current models for core accretion show dust grains embedded in a protoplanetary disk around a young star. Mixing with rotating gas, the dust undergoes inevitable collisions, gradually bulking up to pebble size, then larger. As the scale increases, we move through to planetesimals, bodies of at […]

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A Planet Reborn?

June 29, 2015

Objects that seem younger than they ought to be attract attention. Take the so-called ‘blue stragglers.’ Found in open or globular clusters, they’re more luminous than the cluster stars around them, defying our expectation that stars that formed at about the same time should develop consistent with their neighbors. Allan Sandage discovered the first blue […]

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