Archive for the 'Exo Solar Systems' Category
Jan 22nd, 2008
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, […]
Read more...
Oct 10th, 2007
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 […]
Read more...
May 29th, 2007
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.
Read more...
May 9th, 2007
 There 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.
Read more...
Feb 14th, 2007
 It 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.
Read more...
Jan 24th, 2007
 A quick fly through the nearby universe will show you, well, a whole lot of nothing. But, embedded in the nearest bits of that nothing are 8 spectacular planets, dozens of moons, and hundreds of random bits of rock and ice that, depending on where they orbit, fall into such categories as asteroids, Kuiper belt objects, and comets. Somewhat randomly distributed around (and sometimes on) these celestial objects are little bits of flying metal.
Locally, COROT (vaguely rhymes with Inspector Perot), obtained first light today (image above, credit CNES 2006 - D. Ducros). This orbital observatory will dedicate it self to the search for rocky worlds around other stars. A product of the European Space Agency, COROT will study nearby stars with its 30cm telescope, looking for slight changes in brightness indicative of planetary transits. The images it takes will also be useful for asteroseismology, the study of how stars bump and wiggle in reaction to chemical and thermal processes deep beneath their surfaces. Pre-launch calculations predict that every 150 days (the time COROT will spend studying one area of the sky), COROT could discover 10-40 rocky planets and tens of gas giants. Since the first published discoveries of an extrasolar planet around a pulsar in 1992, and around a normal star in 1995, astronomers have only discovered 209 extrasolar worlds. With COROT, that number could double in as little as 1 year.
Read more...
Jan 7th, 2007
In a universe filled with objects of beauty and power and general awe inspiring wonder I never expected to see dryer lint as a press conference prop.
Its always good to be surprised.
Read more...
|
