Video presentations from the recent Tennessee Valley Interstellar Workshop are beginning to appear online. It's welcome news for those of us who believe all conferences should be available this way, and a chance for Centauri Dreams readers to home in on particular presentations of interest. I published my Closing Remarks at TVIW right after the meeting and will watch with interest as the complete 2017 videos now become available. There are a number of these I'd like to see again. All of this gets me by round-about way to Project Blue, the ongoing attempt to construct a small space telescope capable of directly imaging an Earth-like planet around Centauri A or B, if one is indeed there. For the other talk I gave at TVIW 2017 (not yet online) had to do with biosignatures, and the question of whether we had the capability of detecting one in the near future with the kind of missions now approved and being prepared for launch. This was delivered as part of a presentation and panel...

An object called A/2017 U1, whether it is an asteroid or a comet, is drawing attention because it seems to be an interstellar wanderer. Discovered on October 19 by the University of Hawaii's Pan-STARRS 1 telescope on Haleakala, the object was quickly submitted to the Minor Planet Center by Rob Weryk (University of Hawaii Institute for Astronomy, IFA). Weryk was subsequently able to identify the object in Pan-STARRS imagery from the previous night. Image: This animation shows the path of A/2017 U1, which is an asteroid -- or perhaps a comet -- as it passed through our inner solar system in September and October 2017. From analysis of its motion, scientists calculate that it probably originated from outside our Solar System. Credit: NASA/JPL-Caltech. Thus a nightly search for near-Earth objects may have uncovered an object whose origins lie much further away. A/2017 U1 is about 400 meters in diameter and on a highly unusual trajectory, one that fits neither an asteroid or comet from...

Just how do you go about building a 'super-Earth'? One possibility may be emerging in the study of young debris disk systems with thin, bright outer rings made up of comet-like bodies. Three examples are under scrutiny in work discussed at the recent American Astronomical Society's Division for Planetary Sciences meeting in Provo, Utah. Here, Carey Lisse (JHU/APL) described his team's results in studying the stars Fomalhaut, HD 32297 and HR 4796A. What the scientists are finding is that dense rings of comets can become a construction zone for planets of super-Earth size. The makeup of the material in these ring systems varies, from two that are rich in ice (Fomalhaut and HD 32297) to one that is depleted in ice but rich in carbon (HR 4796A). Take a look at the image below, showing the ring surrounding HR 4796A, and you'll see how strikingly tight the band of dust around this relatively young stellar system is. Image: Gemini Planet Imager observations reveal a complex pattern of...

Eduardo Bendek's ACEsat, conceived at NASA Ames by Bendek and Ruslan Belikov, seemed to change the paradigm for planet discovery around the nearest stellar system. The beauty of Alpha Centauri is that the two primary stars present large habitable zones as seen from Earth, simply because the system is so close to us. The downside, in terms of G-class Centauri A and K-class Centauri B, is that their binary nature makes filtering out starlight a major challenge. Image: The Alpha Centauri system. The combined light of Centauri A (G-class) and Centauri B (K-class) appears here as a single overwhelmingly bright 'star.' Proxima Centauri can be seen circled at bottom right. Credit: European Southern Observatory. If we attack the problem from the ground, ever bigger instruments seem called for, like the European Southern Observatory's Very Large Telescope in conjunction with the VISIR instrument (VLT Imager and Spectrometer for mid-Infrared) that Breakthrough Initiatives is now working with...

Comparative exoplanetology? That's the striking term that Angelos Tsiaras, lead author of a new paper on exoplanet atmospheres, uses to describe the field today. Kepler's valuable statistical look at a crowded starfield has given us insights into the sheer range of outcomes around other stars, but we're already moving into the next phase, studying planetary atmospheres. And as the Tsiaras paper shows, constructing the first atmospheric surveys. Tsiaras (University College, London) assembled a team of European researchers that examined 30 exoplanets, constructing their spectral profiles and analyzing them to uncover the characteristic signatures of the gases present. The study found atmospheres around 16 'hot Jupiters,' learning that water vapor was present in each of them. Says Tsiaras: "More than 3,000 exoplanets have been discovered but, so far, we've studied their atmospheres largely on an individual, case-by-case basis. Here, we've developed tools to assess the significance of...

When we think about the markers of possible life on other worlds, vegetation comes to mind in an interesting way. We’d like to use transit spectroscopy to see biosignatures, gases that have built up in the atmosphere because of ongoing biological activity. But plants using photosynthesis offer us an additional option. They absorb sunlight from the visible part of the spectrum, but not longer-wavelength infrared light. The latter they simply reflect. What we wind up with is a possible observable for a directly imaged planet, for if you plot the intensity of light against wavelength, you will find a marked drop known as the ‘red edge.’ It shows up when going from longer infrared wavelengths into the visible light region. The red-edge position for Earth’s vegetation is fixed at around 700–760?nm. What we’d like to do is find a way to turn this knowledge into a practical result while looking at exoplanets. Where would we find the red edge on planets circling stars of a different class...

Sara Seager often describes the distribution of exoplanets as 'stochastic,' meaning subject to statistical analysis but hard to predict. A good thing, then, that Kepler has given us so much statistical data to work with, allowing us to see the range of possible outcomes when stars coalesce and planetary systems emerge around them. We're not seeing copies of our own Solar System when we explore other stellar systems, but a variegated mix of outcomes. Thus finding a planet with an albedo as dark as fresh asphalt goes down as yet another curiosity from a universe that yields them in great abundance. The planet is WASP-12b, a 'hot Jupiter' of the most extreme kind. Previous work on this heavily studied world has already shown that due to its proximity to its host star, the planet has been stretched into an egg shape, while its day-side temperatures reach 2540 degrees Celsius, or 2810 Kelvin. 94 percent of incoming visible light here is trapped in an atmosphere so hot that clouds cannot...