Exoplanetary Science

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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Kepler-138b: A Mars-Size Exoplanet

June 18, 2015

Astronomers at Penn State, NASA Ames, the University of Chicago and the SETI Institute are publishing news of an exoplanetary first: A planet smaller than Earth whose mass and size have both been measured. Kepler-138b is a Mars-sized world orbiting a red dwarf about 200 light years from Sol in the constellation Lyra. This is […]

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Volcanism and Astrobiology

June 10, 2015

A question in a grad school astrobiology seminar at the University of Washington prompted Amit Misra to go to work on plate tectonics. The movement of huge blocks of a planetary surface is beneficial to life because it prompts recycling, as materials move back and forth between the inside of the planet and the atmosphere. […]

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A Kuiper Belt in the Making

June 2, 2015

The Scorpius-Centaurus OB association is a collection of several hundred O and B-class stars some 470 light years from the Sun. Although the stars are not gravitationally bound, they are roughly the same age — 10 to 20 million years — their formation triggered by a series of supernovae explosions in large molecular clouds. Now […]

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Exoplanet Exploration Organization Proposed

May 26, 2015

We’ve recently looked at the role of small spacecraft, inspired in part by The Planetary Society’s LightSail, a CubeSat-based sail mission that launched last week. It’s interesting in that regard to consider small missions in the exoplanet realm. ExoplanetSat, for example, is a 3-unit CubeSat designed at MIT as a mission to discover Earth-sized exoplanets […]

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A Mass-Radius Relationship for ‘Sub-Neptunes’

May 22, 2015

The cascading numbers of exoplanet discoveries raise questions about how to interpret our data. In particular, what do we do about all those transit finds where we can work out a planet’s radius and need to determine its mass? Andrew LePage returns to Centauri Dreams with a look at a new attempt to derive the […]

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