February 26, 2009 Issue
ASU Dark Sky Observatory—
A Different Kind of Night Life
Special to High Country Press
It is summer twilight. While most college students prepare for illicit nighttime activities, my lab partner and I are driving down a dirt road in the middle of Ashe County along the Blue Ridge parkway towards the Dark Sky Observatory armed with a list of stellar objects and a vat of caffeine.
In 1981, ASU picked this spot for the observatory because here the night approaches ancestral darkness. The road curves along the ridge and suddenly the trees thin. We are looking down the ramparts of some of the world’s oldest mountains onto the distant lights of the piedmont while the setting sun illuminates our 32-inch telescope wrapped up in its dome like a baked potato.
The night always kicks off with the grand dome opening; and it is, in fact, sort of dramatic. The dome splits down its side and shudders open, very much reminiscent of some arriving mother ship. As we carefully perform the complicated rituals of unlocking, powering up, focusing and initializing the telescope along with six thousand (or so) corresponding computer programs, it occurs to me how visual astronomers are—yes, take a second to bask in the obviousness of this. The whole facility is a gleaming, glorified eye that sizes the heavens up and down. And yeah, it looks good.
In layman’s terms, and to the best of my knowledge, here is how it works:
Through a simple series of reflections and refractions, the telescope gathers the light coming from a celestial object and spreads it out. When we look up into the night sky, the starlight that enters our eyes is just the beginning of the energy that is pouring through space and falling down through the atmosphere. Light is energy—electromagnetic radiation to be precise. Our eyes are honed to distinguish colors radiated in the visible band that is just a thin slice of the electromagnetic spectrum.
With our naked eyes, we are not able to detect any light waves that are “tighter” or “looser” then visible light—but a telescope can. Any emitted radiation carries information about its source within the bands of light. An easy way to think about this is to imagine the whole length of a star’s spectrum as its iridescent fingerprint. Every star has this appendage, but various elements and sometimes molecules swimming about on the star’s surface or in its body leave impressions on the light that is always streaming outward.
Spectroscopy is a powerful arm of astronomy that extracts information about celestial objects by analyzing and categorizing light patterns. In the small hours of the morning, conducting spectroscopy by filtering incoming starlight, I feel like an overworked police officer fielding lost children by way of their addresses.
Enabled by the generosity of the North Carolina Space Grant Foundation, I spent this past summer investigating what is, in my opinion, the sexiest topic of cutting edge astronomy: exo-planet host stars. These are stars that are known to have planets in orbit around them.
It has only been a little more than a decade that astronomers have been able to detect extra-solar planets at all. The very first, 51 Pegasi b, was discovered in 1995. Its unofficial name, Bellerophon, aptly identifies it as the rider of the winged horse, Pegasus. The gas giant, whipping around its sun, made itself known through a gravitational tug on its parent star, 51 Pegasus. It has a very slight, telltale wobble in its stride across the sky. By extremely-precise calculations, astronomers were able to characterize the orbit and the mass of the planet.
But the goal of our summer research was not to map star wobbling, but to investigate the interaction between a planet and its star.
The chromosphere is one of the outermost layers of a star. High chromospheric activity can arise from phenomena like sunspots and solar flares. It has been speculated that a gas giant in a tight orbit would exert a noticeable effect on the chromosphere of its host star. Matching the periodicity in chromospheric activity to the orbit of the planet would provide an indirect way to detect the presence of an exo-planet.
After many productive and less productive nights, we had a healthy cache of spectra and highly irregular sleep schedules. Unfortunately, the jury is still out on whether or not this technique is viable, but at the very least we added to the spectral reservoir and at best we began construction on another channel to facilitate the discovery of planets beyond our own solar system.
At present, the Dark Sky Observatory Kline Visitor Center is in construction. Public access will be encouraged and if you are very lucky, you might get a chance to come and peek out through our giant eye upon the terrifying and profound intimacies of our universe.
For more information about the ASU Dark Sky Observatory, click to www.dancaton.physics.appstate.edu/Observatories/DSO/index.htm.
Many thanks to my professors and mentors, Dr Richard Gray and Dr. Jon Saken, as well as my lab partner, Chris Flora.
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