Kepler First Science

Kepler First Science

This is the morning of Kepler. I’m currently sitting in a the Marriot Ballroom watching the speaker, William J Borucki (NASA/Ames) gear up to announcing planets. This amazing mission has been imaging the same rich stellar field over and over looking for planetary transits: the slight dimming of light from a star that comes from an orbiting planet passing between us and that distance star. After 20 minutes of gearing up, he announced 5 new planets with orbital periods between 3.2 and 4.9 days orbiting stars larger than the sun at orbital distances 4.31 to 18.8 times the size of the Earth’s orbit. Because the stars are bigger than the Sun (by an amount not shown in the table), this is hard to quantify – they could be very near the stellar...

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Resonating Worlds

Resonating Worlds

I want to start by saying the following story is drawn from a pre-print, and the planet I’m about to talk about has not yet been directly detected. This is just a really neat little paper that offers a new way to look at things. In a new pre-print over on arXive, astronomers Ignasi Ribas (ICE/CSIC-IEEC, Spain), Andreu Font-Ribera (ICE/CSIC-IEEC, Spain), and Jean-Philippe Beaulieu (IAP, France) announce they have found what may be the smallest planet yet discovered – a 5 Earth mass world – orbiting a cool red dwarf star. They found this potential new planet through its invisible tug-a-war on an already known gas giant. Here’s how the game is played. Some astronomer (or 2 or 12) adopts a star and observers it over and over and over with a...

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In Search of Alien Air

Looking for planets is a difficult task. Planets are physically small (compared to stars), physically faint (compared to stars), and are consistently located next really bright objects (those would be the stars). Looking at planets isn’t much different from looking at bats eating bugs in front of the largest spotlight you’ve ever seen. As the bats swarm in and out of the light, they eclipse a small amount of the spot light, and the fluctuations they create can (with a precise enough detector) be measured (this is an indirect bat detection). The bats can also be detected from the light their little black bodies reflect from the spot light out to an observer. Finally, with night vision goggles (and a lot of care not to actually look at the spot light),...

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All that’s sorta new in Exoplanets

Yesterday’s big afternoon press conference was all about exoplanets. The scientists took us on a tour de force of planet related press releases that went from little M stars and their tiny habitable zone, to a new press release on 28 planets, to planets found around sub-giant stars that were A-stars when they were on the main sequence. The catch was, while none of these stories had previously had related press releases, many of them (but not all) had related published papers or published pre-prints in the arXiv pre-print sever.

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Twilight on Earth,
Morning on Gleise 581c

Twilight on Earth, Morning on Gleise 581c

phot-22c-07-preview.jpgThere are certain questions and dreams that drive society in its quest for the stars. Is there life beyond the Earth? How (and when) will we reach other worlds? What will it take to reach other worlds with life? For a long time, astronomers thought that we were still a long time away from being able to find the type of planets a person can actually stand on. Until within just the past couple weeks, we had assumed that it would take a new generation of space missions – Terrestrial Planet Finder, Darwin, some space-based interferometer – before discovery of these rocky worlds started entering the scientific literature.

But as soon as we think we know something, the universe has a habit of surprising us.

On April 25, the European Southern Observatory announced the discovery of a planet, Gliese 581c, with a mass M sin i* = 5 times the mass of the Earth. This is the smallest world that has thus far been found, and the first nearby world that we are fairly certain we can stand on (or at least sail a boat on). This little world is just 20.48 light years away. Using our fastest current space craft, New Horizons, and traveling at its zippy 10 mi/s, we could be there in just, um, well… 382,828.56 years.

Clearly faster space craft are called for.

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Helix hides Comets in its Core

Helix hides Comets in its Core

169140main_piaa09178-330.jpgIt is easy in astronomy to lump different objects into specific groups. At the top-most level, there are stars, galaxies, planetary systems (including asteroids and comets), and dust-bunnies interstellar and intergalactic media (clouds and nebula). Looking a bit deeper, each of these categories can be nit-picked apart into more sub-categories. For instance, stars can be divided up by energy generation mechanism, or mass, or both. But, astronomy isn’t just the study of a bunch of discrete objects that can be junked into boxes any more than plant science is the study of how a bunch of leaves that can be classified by structure. Both sciences must consider the ecology around discrete objects. Trees grow in forests in symbiosis with other plants and animals, and are both harmed and helped through these synergistic relationships. Stars too exist in rich environments, and when we study stars and their evolution we are also studying the evolution of their planetary systems and of the galaxy they live within. Until recently, it was easy to see the average star as an isolated object on a solitary journey from molecular cloud to planetary nebulae – we simply weren’t able to see anything other than the star and what isn’t seen is easily ignored. Today, however, that is all changing.

As we peer at stars in more wavelengths and in greater detail, we are beginning to find evidence of planetary systems around more and more objects.* As we witness this co-formation of stars and planets it is becoming impossible to stick stars in discrete boxes – Stars and planetary systems must be studied as a whole. This was brought home to me by a newly released Spitzer Space Telescope image of Helix nebula (above right, credit:NASA/JPL-Caltech/K. Su (Univ. of Ariz.)). This favorite object of amateur astronomers appears as a faint swirl of light through the eyepiece of a backyard telescope in a dark location. With Spitzer, it is resolved into concentric rings marking the location of a dead star. Around that dead star are the remnants of a cometary cloud.

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