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Directly Imaged Planet Orbits Sun-like Star

by Paul Gilster | Jun 30, 2010 | Exoplanetary Science | 6 Comments

Exoplanet hunting takes time, a fact that is well demonstrated in the case of a newly confirmed gas giant. Eight times as massive as Jupiter, it orbits a star much like the Sun but at a distance vast enough (300 AU) to place it well within the Kuiper Belt if it were in our own system. 1RXS 1609 b was first reported back in September of 2008 when David Lafrenière (now at the University of Montreal) and team used adaptive optics to take direct images and spectra of the object, which can be seen in the image below. Image: First released in September of 2008: Gemini adaptive optics image of 1RXS J160929.1-210524 and its ~8 Jupiter-mass companion (within red circle). This image is a composite of J-, H- and K-band near-infrared images. All images obtained with the Gemini Altair adaptive optics system and the Near-Infrared Imager (NIRI) on the Gemini North telescope. Credit: Gemini Observatory. This was thought to have been the first planet directly imaged around a Sun-like star, but...

IKAROS Powers Up; LightSail-1 Passes Review

by Paul Gilster | Jun 29, 2010 | Sail Concepts | 6 Comments

The solar sail news continues to be positive, a welcome relief after so many years of delay and frustration. Now that we finally have an operational sail in space, it's worth noting how the Japanese IKAROS sail differs from earlier sail concepts. For IKAROS is designed to use two kinds of power. The first comes from the momentum applied to the sail by photons from the Sun. The second (and this is just one of the areas where the Japan Aerospace Exploration Agency went in a new direction) is produced by the thin film solar cells built into the membrane of the 20-meter (diagonal) sail. Remember that we've been getting helpful imagery from two cameras that separated from the spacecraft and looked back on its operations. The image shown later in this post was taken by the DCAM2 camera, a cylindrical device about six centimeters in diameter and height that was detached from the spacecraft by a spring, as was DCAM1. JAXA is continuing to measure the power generating capabilities of the...

Encouraging News re Red Dwarf Planets

by Paul Gilster | Jun 28, 2010 | Astrobiology and SETI, Exoplanetary Science | 20 Comments

Knowing of my fascination with small red stars, a friend recently asked why they seemed such problematic places for life. M-dwarfs are all over the galaxy, apparently accounting for 75 percent or more of all stars (I'm purposely leaving the brown dwarfs out of this, because we're still learning about how prolific they may be). Anyway, asked my friend, is it just that a habitable planet would have to be so close to the star that it would always present the same side to it? That's tidal lock, and it looks as if it would play havoc with any chances for a stable environment. But maybe not. In the absence of observational evidence, we have to apply models to M-dwarf planets to see what might or might not work, and some very solid modeling out of NASA Ames back in the 1990s showed that there were ways an atmosphere could circulate so as to keep the dark side of the planet from freezing out its atmosphere. This work, by Robert Haberle and Manoj Joshi, was followed by Martin Heath (Greenwich...

Numerous Nearby Brown Dwarfs?

by Paul Gilster | Jun 25, 2010 | Deep Sky Astronomy & Telescopes | 26 Comments

The space-based Spitzer telescope has performed a new study of brown dwarfs, concentrating on a region in the constellation Boötes. Fourteen of the objects, with temperatures ranging between 450 and 600 Kelvin, have been found. These are cold objects in stellar terms, and in fact are as cold as some of the planets we've found around other stars. 450 Kelvin works out to 177 degrees Celsius, or 350 degrees Fahrenheit, the temperature of a moderately hot oven. In fact, it gives me pause to reflect that the focaccia I baked the night before last needed higher temperatures (500 degrees Fahrenheit) than the coolest of these brown dwarfs can supply. Most of the new objects in the Spitzer study are T dwarfs, the coolest class of brown dwarfs known, defined as being less than 1500 Kelvin (1226 degrees Celsius). One of the dwarfs in this study is cold enough that it may represent the hypothetical class called Y dwarfs, part of a classification created by a co-author of the paper, Davy...

Terrestrial Planet Hunt: Nulling Out Starlight

by Paul Gilster | Jun 24, 2010 | Exoplanetary Science | 6 Comments

Combining the assets of multiple telescopes in the technique known as interferometry has a long pedigree. Using a cluster of small telescopes rather than a single gigantic one is a way to achieve high resolution at sharply lower costs. Take a look at this list of astronomical interferometers working from the visible to the infrared and you'll see how widely spread the technique has become as we've moved from earlier long wavelength observations (including the Very Large Array and MERLIN) toward optical installations and submillimeter interferometers and, now under construction, the Atacama Large Millimeter Array. Observing Earth-like planets from space has often been studied in terms of a space-based array, with separated spacecraft operating in tandem, as in the infrared interferometer concept shown in this image (Credit: JPL). Both the now stalled Terrestrial Planet Finder and the canceled Darwin mission from ESA were looking at interferometry concepts that would have used a...

HD 209458b: High Wind Rising

by Paul Gilster | Jun 23, 2010 | Exoplanetary Science | 7 Comments

HD 209458b is perhaps the most persistently studied exoplanet we have, a transiting 'hot Jupiter' that has already revealed a slew of its secrets, including the detection of carbon dioxide, water vapor and methane. I confess that it sometimes seems like black magic to me that we are able to ferret out the signature of organic compounds on worlds we cannot even see. But the transit method is fruitful, and when scientists examine the light of the star during a planetary transit, the tiny portion of that light filtering through the planet's atmosphere can be analyzed. In the case of HD 209458b, we're talking about a three hour transit, one that occurs every 3.5 days as this 'hot Jupiter' makes its rounds. Now we learn that the carbon dioxide detected here can also be studied in terms of its velocity. The result: We have indications of a vast storm, a wind flow that's moving at speeds that defy the imagination. Ignas Snellen (Leiden Observatory, The Netherlands) led the team that...

Keeping an Eye on Io

by Paul Gilster | Jun 22, 2010 | Outer Solar System | 19 Comments

Suppose for a moment that you have some novel ideas about astrobiology on Io. The idea seems extreme, but there are scientists who argue for the notion, as we'll see in a moment. In any case, if you wanted to observe Io, how would you go about it? The best solution is a spacecraft, as it was when Voyager 2 sped through the Jupiter system and discovered what tidal effects can do to a small moon. The Galileo probe, despite the failure of its high-gain antenna, was able to send up-close data about both Europa and Io, confirming that the latter's volcanic activity was 100 times greater than what we experience on Earth. And then there was Cassini's lovely view. Image: Gliding past Jupiter at the turn of the millennium, the Cassini spacecraft captured this awe inspiring view of active Io with the largest gas giant as a backdrop, Credit: Cassini Imaging Team, Cassini Project, NASA. But the Voyagers are now close to leaving the Solar System, while Galileo was sent to its destruction in the...

Brown Dwarf Planets and Habitability

by Paul Gilster | Jun 21, 2010 | Astrobiology and SETI | 23 Comments

Are planets common around brown dwarfs? We aren't yet in a position to say, but the question is intriguing because some models suggest that the number of brown dwarfs is comparable to the number of low-mass main sequence stars. That would mean the objects -- 'failed' stars whose masses are below the limit needed to sustain stable hydrogen fusion -- could be as plentiful as the M-dwarfs that far outnumber any other type of star in the galaxy. If planets form around brown dwarfs, then we have to add them to our list of possible abodes for life. Evidence for Brown Dwarf Planet Formation But first, to the planet question. We can find suggestive analogs to planet formation around brown dwarfs in nearby space. The star Gl 876, some fifteen light years away, is not a brown dwarf, but this M-dwarf is only 1.24 percent as luminous as the Sun, with most of its energy being released at infrared wavelengths. We now know that at least three planets, two of them gas giants similar to Jupiter,...

Protecting the Lunar Farside

by Paul Gilster | Jun 18, 2010 | Astrobiology and SETI | 10 Comments

Long-term thinking means planning for the consequences of things that are beyond our current capacity. What happens on the farside of the Moon is a case in point. Getting humans back to the Moon is going to happen sooner or later, and one day we will have bases there, as well as a human or robotic presence at the L4 and L5 Lagrangian points of the Earth-Moon system. That means an ever growing blanket of electromagnetic radiation from our various activities. At the same time, we want to protect the farside, which is ideal for future radio telescope or phased array detectors. What to do? Italian physicist Claudio Maccone has brought this issue to Vienna, speaking before the United Nations Committee on the Peaceful Uses of Outer Space. Maccone is proposing a radio-quiet zone on the farside that will guarantee radio astronomy and SETI a defined area in which human radio interference is impossible. It's an idea with a pedigree, going back to 1994, when the French radio astronomer Jean...

The Epsilon Eridani Factor

by Paul Gilster | Jun 17, 2010 | Missions | 25 Comments

When I was a kid, interstellar destinations were sharply defined. It seemed obvious that you didn't even consider Alpha Centauri, because a double-star primary system surely wouldn't allow stable planetary orbits. So you looked around for single stars. Moreover, these should be stars a lot like the Sun, so that when Frank Drake began SETI with Project Ozma, it made all the sense in the world to focus on Tau Ceti and Epsilon Eridani. Both were similar enough to our own star to suggest that they would have planets, and maybe one like ours. For that matter, we had no idea in those distant days whether the Sun was a statistical fluke in having planets or simply a garden-variety star with a system that was all but inevitable. These days we keep finding interesting planets, but so far (other than perhaps in the Gliese 581 system) we haven't found anything enough like the Earth to consider any nearby system an obvious target for an interstellar probe. All that may change, and swiftly, when...

Views of IKAROS (and a Memory)

by Paul Gilster | Jun 16, 2010 | Sail Concepts | 7 Comments

This is what a solar sail looks like in space. The images below were taken by a camera flown aboard the IKAROS mission and then separated from it using a spring, according to the Japan Aerospace Exploration Agency (JAXA). These pictures (and you can find several more here) take me back to my first reading of Cordwainer Smith's 'The Lady Who Sailed the Soul,' in which a far future sail mission involving a sail tens of thousands of kilometers across plays against the tangled relationship of two lives (full text here). IKAROS may be far smaller, but if seeing a deployed sail in space doesn't fire the imagination, what will? A brief snippet from the story: The first sailors had gone out almost a hundred years before. They had started with small sails not over two thousand miles square. Gradually the size of the sails increased. The technique of adiabatic packing and the carrying of passengers in individual pods reduced the damage done to the human cargo. It was great news when a sailor...

750 Planetary Candidates from Kepler

by Paul Gilster | Jun 15, 2010 | Exoplanetary Science | 36 Comments

The release of the first 43 days of Kepler data has demonstrated just how powerful a planet-hunting technology we've put into space. Listen to principal investigator William Borucki (NASA Ames) in a video released yesterday by NASA television: "We're releasing data on 156,000 stars that we've been monitoring with the Kepler mission for 43 days, the first dataset. In these data are some 750 planetary candidates. Some of those are actual planets, some are false positives. Our science team is looking at 400 of those candidates with ground-based telescopes, to figure out which are planets, which aren't." Borucki assumes about fifty percent of the candidates will be false positives, eclipsing binary stars, starspots, or other misleading signals. Now it's in the hands of ground-based telescopes in the Canary Islands, Texas, Arizona and Hawaii to comb through these findings to make the call. The team is also releasing the data for the remaining 350 candidates to the world community of...

CoRoT & Hayabusa: Starting the Week Right

by Paul Gilster | Jun 14, 2010 | Exoplanetary Science, Outer Solar System | 10 Comments

If we ended last week on a high note with the successful deployment of the IKAROS sail, this week started equally well with the return of JAXA's Hayabusa spacecraft, whose re-entry capsule has now been recovered from the Australian desert and is intact. We'll learn once it gets back to Japan how much material from asteroid Itokawa it was able to acquire. But what an exciting finish to this mission, and what a accomplishment by JAXA to survive battery failures, communications problems, engine issues and more and bring this mission home. [youtube gfYA4f-AIL0 500 375] The canister return is the fruit of a seven year journey that saw Hayabusa touch down on Itokawa back in 2005, and although the many glitches caused a three year delay in its return, Hayabusa may well offer us at least trace amounts of material from the asteroid, valuable in helping us understand not only the asteroid itself but also the early history of the solar system. We have so few instances of material recovered from...

Oort Finding: Many Comets From Other Stars

by Paul Gilster | Jun 11, 2010 | Deep Sky Astronomy & Telescopes | 15 Comments

Here's something to put the cap on a scintillating week in space science. It's from Hal Levison (SwRI), who has led an international team in computer simulations focusing on our Sun's earliest days. It turns out that our older assumption that the Oort cloud of comets surrounding the Sun came from the Sun's protoplanetary disk may not be accurate. Yes, our system produced comets, but not enough to account for the Oort's entire population, which swarms in a vast sphere that extends half the distance to Alpha Centauri. Says Levison: "If we assume that the Sun's observed proto-planetary disk can be used to estimate the indigenous population of the Oort cloud, we can conclude that more than 90 percent of the observed Oort cloud comets have an extra-solar origin." Image: Comet McNaught, possibly an interloper from another star, according to recent work. Credit: Stéphane Guisard. The process works like this: We believe the Sun formed in a cluster containing hundreds of closely packed...

IKAROS Deployment in Translation

by Paul Gilster | Jun 11, 2010 | Sail Concepts | 4 Comments

For those of you interested in the key IKAROS post describing the final deployment of the sail, Lionel Ward has been so kind as to translate it in context. I'm leaving out the actual photographs, which you can see via the links posted in my previous IKAROS coverage -- and also here in context -- but here is the text from JAXA: ------- 2010?6?11?[??]? A world first! Solar Powered Electrical Sail deployment and power generation is successful! ????????????????&????? On June 8th the finalization of the primary deployment was executed, and on June 9th the secondary deployment was executed. 6?8?????????????????6?9?????????????? IKAROS’ state at the end of the primary is detailed over on the Ikaros blog. ???????????????????????????? Upon sending the command to initiate secondary deployment, a state of nervousness persisted in the command center during the 46 second propagation delay (the separation from earth is 7.4 million km!) until the initial data could be seen. That deployment had...

IKAROS Deployment Photos Arriving

by Paul Gilster | Jun 11, 2010 | Sail Concepts | 1 Comment

IKAROS now appears to be fully deployed and generating power from its photovoltaic cells. The IKAROS blog even has a photo of the cake with which the sail team celebrated the success, but you'll also want to go to this IKAROS page for a look at further imagery, one of which is the photo shown below. The page has four similar photographs from different cameras aboard the spacecraft, and if I'm reading this right, more photos will be posted here as they become available. JAXA has also made available this news release about the deployment. Lionel Ward, our Japanese translator extraordinaire, will be sending translations of the IKAROS blog postings and recent tweets from JAXA later today, and I'll post these as a way of archiving the information here. This afternoon (1800 or so UTC) I'll have today's regular Centauri Dreams post up, but I wanted to share this image and give you the pointer for more as soon as possible. What an achievement this mission has turned out to be even this early...

? Pictoris b: A New Planet and Its Implications

by Paul Gilster | Jun 10, 2010 | Exoplanetary Science | 2 Comments

One of the problems with determining how planets form is the nature of the dusty gas-rich disks that surround their stars. We're learning as we study these things that the disks around young stars disperse quickly in astronomical terms, within several million years. Thus finding a massive planet around a young star like Beta Pictoris is noteworthy. It demonstrates that such planets can form in short-order. What's doubly fascinating about the new find is that this planet was discovered by direct imaging techniques, and that it is as close to its star as Saturn is to ours. Have a look at the imagery below, made using the European Southern Observatory's Very Large Telescope and an adaptive optics instrument that removes atmospheric blurring and other effects. It's a composite showing the faint source in the 2003 image and contrasting it with the motion of the object as seen in the autumn of 2009. The object can be seen to have moved to the other side of the disk. As we only have direct...

Holding for Later Today

by Paul Gilster | Jun 10, 2010 | Administrative | 4 Comments

Update: As of 1611 UTC, the IKAROS blog is reporting "IKAROS state has been confirmed to be good." More images and data are in the works, but we're not likely to see anything until tomorrow. It's getting late in Japan (2306 JST as I write, or 1406 UTC), and although a JAXA tweet promised new photos for today, the IKAROS blog is still showing the same deployment image we looked at yesterday. More as it becomes available and, naturally, I'm also following the fortunes of Hayabusa, now on final approach to the Woomera Test Range in South Australia. Re-entry is targeted for June 13. Meanwhile, I'm holding on a story (not on IKAROS) that comes off embargo this afternoon and will be posting today's main entry in a few hours.

IKAROS Sail Deployment in Progress

by Paul Gilster | Jun 9, 2010 | Sail Concepts | 5 Comments

Update: The IKAROS blog reports "The operation ended today as planned." That must count as good news for the sail, now 7,480,787 kilometers from Earth, but we still need confirmation that the sail's 'secondary' deployment is now complete. Maybe this is it: Japanese space journalist Mitsunari Kita, who is attending a press conference re the Hayabusa mission, has sent out a tweet (@kitamitsunari) congratulating the IKAROS team on full deployment of the sail (1805 UTC). What extraordinary times these are for the Japan Aerospace Exploration Agency (JAXA). We are in the midst of an interplanetary solar sail mission even as the Hayabusa asteroid explorer prepares for re-entry over Australia, an event that should occur around 1400 UTC on June 13. The Hayabusa craft will release its 16-inch-wide entry capsule some three hours before landing. We've concentrated on IKAROS in these pages, but what a story Hayabusa has been, launched in 2003 to explore the asteroid Itokawa, which it did, but not...

IKAROS Nears Full Deployment Attempt

by Paul Gilster | Jun 8, 2010 | Sail Concepts | 3 Comments

Update: The IKAROS team has not confirmed full deployment of the sail, but does indicate we'll have an update tomorrow. The IKAROS solar sail is partially deployed but the complete deployment was delayed while the mission's engineers tried to figure out why the spacecraft's spin rate has been increasing. JAXA's updates are in Japanese, but the Planetary Society's Emily Lakdawalla seems to be more skilled at untangling Google Translate than I am and has also used a translation from a user on the excellent unmannedspaceflight.com site to come up with IKAROS details. Thus we learn that the sail is currently deployed about five meters. A new update just in from JAXA points to an attempt at full sail deployment just a few hours from now. This video shows the process at work. [youtube 7Mb47w0vB04 500 375] From what JAXA says, there is no danger to the spacecraft from the increased spin rate, but the pause in deployment arose simply because the team wanted to pin down an explanation for the...

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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