'First light' from any new telescope is an exciting moment, but never more so than with the Kepler instrument. Dust cover off, the space-based telescope is now looking at its target, a starfield in the Cygnus-Lyra region of the Milky Way. Kepler's full field of view covers a 100-degree swath of sky, containing scenery like NGC 6791, an eight-billion year old cluster some 13,000 light years from us, as seen in the image below. Image: The area pictured is 0.2 percent of Kepler's full field of view, and shows hundreds of stars in the constellation Lyra. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft's dust cover was jettisoned. Credit: NASA/JPL-Caltech. Loosely bound, the stars in NGC 6791 have begun to spread out from each other, the signature of what is called an 'open cluster.' The view is impressive but also blurry, an intentional effect that is being used,...

Kepler's dust cover has now been jettisoned, meaning the search for extrasolar 'Earths' is not long from commencing. The cover stayed in place for so long because the spacecraft's photometer had to make measurements of electronic noise that will later have to be removed from the science data. Mission engineers will now continue with the calibration process for several weeks using images of actual stars. Our debates over the 'rare Earth' hypothesis will be getting firm data in short order because of Kepler. Three years from now, having had time to detect terrestrial-class planets in the habitable zone of their stars, confirm the detections and further examine the results, we should have at least a sense of how common such planets are. Finally we can move beyond informed speculation with the sort of hard data we need. And as far as the first terrestrial planet detection in the habitable zone, CoRoT may just beat Kepler to the punch. Meanwhile, the astrobiological side of the 'rare...

Depressing economic times inevitably cast a pall over our space plans. That makes it important to keep our eyes on the big picture -- what we hope to accomplish -- rather than succumbing to the fatigue induced by seeing good science pushed back on the calendar year after year. Will we get a terrestrial planet finder off in the next fifteen years? Will we get back to the Jupiter system some time before 2030? I don't know, but times like these require persistence, patience, and continued hard thinking. I was musing about this while looking through a paper Dave Moore passed along recently. It's a discussion of where we need to go now that we've got missions like CoRoT and Kepler in space and the James Webb Space Telescope in the picture for 2014. Tom Greene (NASA Ames) and colleagues from various institutions are looking at a space telescope with relatively modest aperture in the 1.4-meter range, one that would use a coronagraph to block the light of central stars to allow direct...

Spotting transiting planets is what missions like CoRoT and Kepler are all about. The next step, getting a read on what's in the atmosphere of any transiting, terrestrial world, is going to be tricky. The biomarkers like ozone and methane, so crucial for determining whether there's life on a distant planet, are beyond the range of existing spacecraft. But the the next generation James Webb Space Telescope is also in the works, scheduled for launch in 2013. For nearby Earth-class worlds, JWST may be up to the task, at least for terrestrial planets that transit. In fact, if Alpha Centauri A turns out to have a transiting Earth-like planet (a major if!), it would take only a few transits to study the light filtering through its atmosphere to look for signs of life. Alpha Centauri is problematic in any case, but a recent study shows that the method -- breaking down the star's light during a transit to look for the characteristic markers -- could be extended to other stars, provided...

Most stars in our region of the galaxy are low-mass M-dwarfs, making the investigation of their planetary systems quite interesting. If we learn that stars like these, which comprise over 70 percent of the galactic population, can be orbited by Earth-like planets, then the galaxy may be awash with such worlds. But some models have indicated that Earth-sized planets would be rare around these stars, working on the assumption that scaled-down versions of the Sun's protoplanetary disk would tend to produce only low-mass planets. Clearly, we need to know more about the masses of such inner disks, since available mass seems to be a key to the formation of habitable planets. Extrapolate the early nebula from our own Solar System to lower protoplanetary disk masses around M-dwarfs and the terrestrial worlds that form are no larger than Mars -- they're small, dry, worlds unlikely to develop life. Low-mass disks would seem to lead to low-mass planets. But what if those M-dwarf protoplanetary...

We now have on the order of 335 confirmed exoplanets, with an ongoing race between the CoRoT and Kepler teams to find the first Earth analog in the habitable zone around another star. CoRoT's shorter observation cycles make finding a terrestrial world around a G-class star problematic -- the orbit would necessarily be on the order of a year, and the transit would then have to be confirmed with additional transits and whatever radial velocity observations could be mustered. But CoRoT just might find an Earth-class planet in the habitable zone of a K-class star, so we shouldn't assume Kepler is necessarily going to win the 'habitable Earth' race. I mentioned a few days back that the Planetary Society has unveiled its new Catalog of Exoplanets, a fine resource with the basics on detection methods and a glossary that complements a catalog filled with helpful orbital animations. If you want to get a quick read on a given exoplanet, take a look here. Some of these planets have gone beyond...

An email from Greg Laughlin confirms that the planet HD 80606b has indeed been caught in a transit, a roughly 15 percent probability now turned into hard data. Laughlin (UCSC) and team recently wrote up their Spitzer infrared observations of this mutable gas giant, a world with an orbit so eccentric that it almost mimics a comet, swinging out to 0.85 AU from its star, then rushing in to a breathtaking 0.03 AU for a brief, searing encounter. The possibility of a transit has been on his mind ever since. "If you could float above the clouds of this planet, you'd see its sun growing larger and larger at faster and faster rates, increasing in brightness by almost a factor of 1,000," Laughlin said at the end of January in this JPL news release. His team captured what happens on this world as its atmosphere heats rapidly and produces 5 kilometer per second winds that create vast storm systems, gradually easing as the planet moves away from its star. I've already run the resultant image...

Alan Boss, whose new book The Crowded Universe will soon be on my shelves (and reviewed here), has driven the extrasolar planet story to the top of the news with a single statement. Speaking at the American Association for the Advancement of Science's annual meeting in Chicago, Boss (Carnegie Institution, Washington) said that the number of Earth-like planets in the universe might be the same as the number of stars, a figure he pegged at one hundred billion trillion. A universe teeming with life? Inevitably. The Telegraph quoted Boss on the matter in an early report on his presentation: "If you have a habitable world and let it evolve for a few billion years then inevitably some sort of life will form on it," said Dr Boss. "It is sort of running an experiment in your refrigerator - turn it off and something will grow in there. "It would be impossible to stop life growing on these habitable planets." Few Centauri Dreams readers would disagree with the notion that life may be common in...

Will the first 'super-Earth' in the habitable zone of its star be found around a red dwarf? An M5-dwarf with both mass and radius about a quarter that of the Sun would have 1/200th Sol's luminosity. That's interesting for transit purposes, for a planet in the habitable zone around this star would be close in indeed, some 0.074 AU out, with an orbital period of 14.8 days. Its transit probability would correspondingly be raised by a factor of three compared to the Earth-Sun system. The result, as laid out by the transit survey called MEarth: Detecting such planets should be possible from the ground. Take a look at the live video of what MEarth is doing. Based at the Fred Lawrence Whipple Observatory on Mt. Hopkins in Arizona, the team works with 1976 nearby red dwarfs, visiting each repeatedly in hopes of snaring an ongoing transit, whose information would then be routed to larger instruments for confirmation. They're looking at targets spread over the entire celestial northern...

The COROT mission's 27-cm telescope has discovered the smallest exoplanet yet, with a diameter less than twice that of Earth. COROT-Exo-7b orbits a Sun-like star and highlights the ongoing space-based investigation into rocky worlds that is drawing ever closer to an Earth-mass object. This is the kind of work COROT was designed to do, flagging planetary transits across the face of a star from an orbital perch that allows long periods of uninterrupted observation and the chance to measure the size of the planets found. ESA's Malcolm Fridlund discusses the significance of the find: "This discovery is a very important step on the road to understanding the formation and evolution of our planet. For the first time, we have unambiguously detected a planet that is 'rocky' in the same sense as our own Earth. We now have to understand this object further to put it into context, and continue our search for smaller, more Earth-like objects with COROT." Finding a 'super-Earth' is one thing when...

I absolutely love the image below, so I decided to run it at full size although it doesn't quite fit the column width. You're looking at the result of recent work from the California & Carnegie Planet Search team, which used data from the Spitzer Space Telescope to produce what is probably the most accurate image yet of an exoplanet. It's not an actual photographic image, of course, but it's better than an artist's interpretation because it's based on highly realistic simulations. The planet in question is HD 80606b, which circles a star about 200 light years from Earth. This is a highly interesting place, some four times the mass of Jupiter and moving within a 111-day orbit around its star. What makes it stand out is the incredible eccentricity of its orbit. We're talking about a world that for most of its orbit is at distances that would be between Venus and Earth here in our system. But then it swoops in ever closer to its primary until it closes to within 0.03 AU, an encounter it...

Could we find evidence of vegetation on distant exoplanets? The answer may be yes, according to recent work by Luc Arnold (Observatoire de Haute Provence) and team. If green vegetation on another planet is anything like what we have on Earth, then it will share a distinctive spectral signature called the Vegetation Red Edge, or VRE. The new paper creates climate simulations that explore whether planets with a distinctively different climate than modern Earth's could be so detected. Two earlier eras are useful here. The Last Glacial Maximum (LGM) occurred 21,000 years ago, with global temperatures on the order of 4 degrees Celsius colder than today, and a significantly lower sea level that produced more land surface. The Holocene, 6,000 years ago, is marked by a rising sea level amidst the de-glaciation occurring in the northern hemisphere. Perhaps the most striking contrast with today would be the Sahara, much more laden with vegetation than at any time since. Both provide a useful...

Our second transiting Neptune-mass planet has been discovered via the HAT Network of small, automated telescopes maintained by the Harvard-Smithsonian Center for Astrophysics. HAT-P-11b is described by Greg Laughlin at systemic (thanks to many who sent this link): HAT-P-11b is quite similar in mass and radius to Gliese 436b, and it's actually somewhat larger than Neptune on both counts. When the mass and radius are compared to theoretical models, it's clear that, like Gliese 436, it's mostly made of heavy elements (that is, some combination of metal, rock and "ice") with an envelope of roughly 3 Earth masses of hydrogen and helium). It's completely dwarfed when placed next to an inflated hot Jupiter, HAT-P-9b, for instance... The advantages of a detected transit are great. Couple the transit light curve with radial velocity measurements and you can work out the mass and radius of the transiting planet. Moreover, the opportunity to investigate planetary atmospheres comes into play...

If, as we have often speculated in these pages, there is a brown dwarf closer to us than the Centauri stars, it may well be the WISE mission that finds it. The Wide-field Infrared Survey Explorer is a 40 cm telescope cooled below 17 K (-430 Fahrenheit) that will image the entire sky in four infrared wavelengths. If we're looking for nearby brown dwarfs, an all-sky survey like this is the way to go, because such stars should be distributed uniformly in the space around us. According to information Amanda Mainzer (JPL) presented yesterday at the American Astronomical Society meeting in Long Beach (CA), brown dwarfs are now thought to make up two-thirds of the stars in our stellar neighborhood, most of them as yet undetected. One of them might well be closer than the 4.3 light years that separate us from Alpha Centauri. And WISE should be up to the challenge of finding it, being able to detect cool brown dwarfs (down to 200 K) at Centauri distance and objects down to Jupiter-mass if...

The American Astronomical Society meeting now in session in Long Beach (CA) is already making news. Led by Michael Jura (UCLA), a team of scientists has used Spitzer Space Telescope data to study six white dwarf stars that are surrounded with the remains of asteroids. The assumption here is that these materials are a likely indication of planetary formation in these systems, for they're the same materials that go into making up the Earth and other rocky worlds in our own Solar System. "If you ground up our asteroids and rocky planets, you would get the same type of dust we are seeing in these star systems," says Jura, who presented the results at the meeting this morning. "This tells us that the stars have asteroids like ours -- and therefore could also have rocky planets." When a star like our Sun reaches the end of its life and becomes a red giant, it consumes any inner planets and perturbs the orbits of the surviving planets and asteroids. A white dwarf is the end result of this...

The title of yesterday's post -- 'The Odds on Centauri' -- would fit well with today's musings. Alpha Centauri makes us ponder the odds not just in terms of interstellar bets and future space probes, but also in terms of the likelihood of life around these stars. And after all, 2008 saw significant work on this question, including the contributions of Philippe Thébault (Stockholm Observatory) and colleagues, whose studies of Centauri A and B show that while stable planetary orbits exist there, the odds on those planets forming in the first place are long. Greg Laughlin (UC-Santa Cruz) isn't necessarily daunted by this work (he explains why here), but the planet-hunter extraordinaire is realistic about life-bearing planets in this environment, and even more judicious about the possibility of a technological society making its home in the system. The question rises naturally out of recent publicity given the 20th Century Fox film The Day the Earth Stood Still, in which it was...

A new camera called OPTIC (Orthogonal Parallel Transfer Imaging Camera), built at the University of Hawaii, has clarified our view of the distant world known as WASP-10b. Transits are helpful because they allow us to measure the size of the observed planets, and in this case, WASP-10b turns out to be not one of the most bloated exoplanets yet found, as once thought, but one of the densest. Orbiting some 300 light years from Earth, the planet's diameter is now known to be only six percent larger than Jupiter's, although it is three times more massive, with a corresponding density three times that of Jupiter. OPTIC is mounted on the University of Hawaii's 2.2-meter telescope on Mauna Kea. If you compare what it can do with its highly sensitive and stable detector to the best results from charge-coupled devices (CCDs), you find a photometric precision two to three times higher. According to this news release from the university's Institute for Astronomy, that's comparable to the most...