March 2017

Ceres: Axial Tilt and Surface Ice

March 23, 2017

Earth’s axial tilt (its obliquity) is 23.5 degrees, a significant fact for those of us who enjoy seasonal change. The ‘tilt’ is the angle between our planet’s rotational axis and its orbital axis. If we look at Earth’s obliquity over time, we find a 41,000 year cycle that oscillates between 22.1 and 24.5 degrees. Here […]

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Rosetta: Chronicling Cometary Change

March 22, 2017

Learning about the changes that occur on a cometary surface over time was a primary goal of the European Space Agency’s Rosetta mission, which orbited comet 67P/Churyumov-Gerasimenko between August 2014 and September 2016. This was a period when the comet was swinging through the inner Solar System as it closed to perihelion. Now we have […]

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Runaway Stars in Orion

March 21, 2017

Unexpected things can happen when you’re looking for exoplanets. Ask Kevin Luhman (Penn State), whose search for free-floating planets in the Orion Nebula is now telling us something interesting about star formation in general. In a small region dominated by young stars called the Kleinmann-Low Nebula, some 1300 light years from Earth near the center […]

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Star in Tight Orbit around Black Hole

March 20, 2017

Beyond their obvious value in advancing our knowledge, astronomical discoveries can be thought of as exercises for the imagination, making us think about what we would see if we were actually near the phenomenon being observed. The view from a planet deep in a globular cluster can only be spectacular, and has been the subject […]

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Giant Planet Clues to a Debris Disk Anomaly

March 17, 2017

A massive young planet on the borderline between gas giant and brown dwarf is telling us a bit more about planet formation in general, and circumstellar disk dynamics in particular. Known as HD 106906b, the world is 11 times the mass of Jupiter and no more than 13 million years old. Its position 650 AU […]

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Titan: Nitrogen Bubbles and ‘Magic Islands’

March 16, 2017

With Cassini now in the final stages of its mission, we can look forward to just one more close flyby of Titan, the 127th targeted encounter, on April 22. ‘Targeted’ means that Cassini has to use its thrusters to position itself optimally for the flyby. The first of the images below, by contrast, comes from […]

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JAXA Sail to Jupiter’s Trojan Asteroids

March 15, 2017

I like the way Jun Matsumoto approaches his work. A researcher with JAXA (Japan Aerospace Exploration Agency), Matsumoto is deeply involved in the design of the space sail that will pick up where Japan’s IKAROS left off. Launched in 2010, the latter was a square sail 14 meters to the side that demonstrated the feasibility […]

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TRAPPIST-1h: Drawing on K2 Data

March 14, 2017

The data recently made available from Campaign 12 of K2 (the Kepler spacecraft’s two-reaction wheel mission) is already paying off in the form of information about the outermost planet in the TRAPPIST-1 system. Campaign 12 (described in Kepler Data on TRAPPIST-1 Coming Online) began on December 15 of 2016 and ran until March 4 of […]

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Fast Radio Bursts: Signature of Distant Technology?

March 13, 2017

We have a lot to learn about Fast Radio Bursts (FRBs), a reminder that the first of these, the so-called Lorimer Burst (FRB 010724) was detected only a decade ago. Since then we’ve found 16 others, all thought to be at cosmological distances. The 2015 detection of FRB 150418, at first thought to have left […]

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HD 219134: A Nearby System with Multiple Transits

March 10, 2017

While we’ve all had our eyes fixed on TRAPPIST-1 (amid the still lingering excitement of the discovery of Proxima Centauri b), news about another stellar neighbor has caused only a faint stir. But what’s happening around HD 219134 (Gliese 892) is noteworthy, and it’s interesting to see that Michaël Gillon (University of Liège – Belgium) […]

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