Autumn 2014 - Volume 43, Number 4
Table of Contents
[16] Posters from the ASP’s 2014 Conference
Within this issue are five of the 55 posters that were presented at the 2014 ASP Conference in Burlingame, California. Here’s an excerpt from one of them: “From Picas to Pixels: An Astro 101 e-book”, by Stephen Shawl et al.
[28] Finding Habitable Worlds Around Other Stars, Geoff Marcy
Astronomers are getting a first glimpse of the possibilities of life elsewhere in the universe.
[36] Flying the Infrared Skies: An Authentic SOFIA Educator Experience, James Manning
I’ve long been associated with SOFIA, so it was great to finally partake in a flight.
[45] Astronomy in the News
Rosetta arrives at a comet, clear skies and steamy water vapor have been found on an alien planet, and the distance to the Pleiades is recalibrated — these are some of the items that recently made news in the astronomical community.
Departments
[4] Perspectives, Paul Deans
New Wonders to Behold
[5] First Word, Linda Shore
A Moment of Science
[7] Annals of Astronomy, Clifford Cunningham
An 850-year-old “Dark Star”
[8] Astronomer’s Notebook, Jennifer Birriel
Milky Way Satellites as Proxies for Galaxy Evolution?
[10] Planetary Perspectives, Emily Joseph
A Close Encounter of a Cometary Kind
[11] Armchair Astrophysics, Christopher Wanjek
Takes Three to Tango?
[13] Reaching Out, David Prosper & Vivian White
Night Sky Network: Study of Amateur Astronomers and Their Audiences
[52] ASP Tidings
Meet Your New Board Members
[55] Sky Sights, Paul Deans
A Look Ahead to 2015
[58] Reflections I, Paul Deans
The Gift that Keeps on Giving
[59] Reflections II, ISRO
MOM’s Mars
From Picas to Pixels: An Astro 101 e-book
by Stephen Shawl et al
What happens when a publisher discontinues publishing a textbook? That was the dilemma we were presented with. Given that we know we have a high-quality product that can contribute to student understanding of science in general and astronomy in particular, and that significant efforts had already been expended on the project, we decided to self-publish, even knowing that the challenges, and the gamble in terms of time and personal expense, were great.
We present the end result: a completed publication in various e-book formats and with links to the Discovering Astronomy Concept Videos made for the book.
Finding Habitable Worlds Around Other Stars
by Geoff Marcy
Occasionally, during the course of human history, we can sense that a great discovery is imminent. Scientific discoveries often happen with some preamble, some preparatory work, or some prior experiments, and give us a chance to sense that we’re in a great moment of history.
A fine example is the Apollo era. Those of us alive in the 1960s can remember that each successive mission gave us a sense that we might well make it to the Moon. That was a moment when you could anticipate this great achievement by humanity. Another one that comes to mind is cracking the code of DNA for humans — the human genome. For years in advance you could almost smell the DNA that was being cracked by the biologists. And now we know the composition of the DNA that makes us human. I think we’re at another such moment, and it involves the search not just for planets around other stars, but planets that might be suitable for life.
Flying the Infrared Skies: An Authentic SOFIA Educator Experience
by James Manning
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a unique NASA facility: it’s a telescope that takes off and lands. Sporting a primary mirror 2.5 meters (100 inches) in diameter tucked into the rear of a short-bodied Boeing 747, the flying observatory does its work at altitudes that can exceed 40,000 feet. Up there, it’s above enough of Earth’s atmosphere to fill in the infrared gap that Earth-bound observatories encounter because those longer-wavelength photons are blocked from reaching the ground by Earth’s atmosphere. Operated in partnership with the German Aerospace Center, this telescope/aircraft combination provides opportunities not only for learning more about the universe, but also for bringing numerous people along for the flight — including teachers.
In May 2014, I had the privilege of taking part in one of these flights as an E/PO escort. SOFIA and I go back a long way, and I’ve been variously associated with it for much of its development history.So it was gratifying to finally witness this program in action.
Half of all Exoplanet Host Stars are Binaries
National Optical Astronomy Observatory
Imagine living on an exoplanet with two suns. One, you orbit and the other is a very bright, nearby neighbor looming large in your sky. With this “second sun” in the sky, nightfall might be a rare event, perhaps only coming seasonally to your planet. A new study suggests that this could be far more common than we realized.
The NASA Kepler Space Telescope has confirmed about 1,000 exoplanets, as well as thousands more stars considered “Kepler objects of interest”, dubbed KOIs — stars that could possibly host planets. Until now, there has been an unanswered question about exoplanet host stars; how many host stars are binaries? Binary stars have long been known to be commonplace — about half the stars in the sky are believed to consist of two stars orbiting each other. So, are stars with planets equally likely to have a companion star, or do companion stars affect the formation of planets? A team of astronomers, led by Dr. Elliott Horch, Southern Connecticut State University, have shown that stars with exoplanets are just as likely to have a binary companion: that is, 40% to 50% of the host stars are actually binary stars. As Dr. Horch said, “It’s interesting and exciting that exoplanet systems with stellar companions turn out to be much more common than was believed even just a few years ago.”
Their study makes use of very high spatial resolution observations that were carried out on the WIYN telescope located on Kitt Peak in southern Arizona and the Gemini North telescope located on Mauna Kea in Hawaii. The technique used by the team is called speckle imaging and consists of obtaining digital images of a small portion of the sky surrounding a star of interest, 15 to 25 times a second. The images are then combined in software using a complex set of algorithms, yielding a final picture of the star with a resolution better than that of the Hubble Space Telescope.
By using this technique, the team can detect companion stars that are up to 125 times fainter than the target, but only 0.05 arcseconds away. For the majority of the Kepler stars, this means companion stars with a true separation of a few to about 100 times the Sun-Earth distance. By noting the occurrence rate of these true binary companion stars, the discoveries can be extended to show that half of the stars that host exoplanets are probably binaries.
