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Star Search

A Middlebury astrophysicist blazes a cosmic trail


Published March 26, 2008 at 10:10 a.m.

Like their Hollywood counterparts, some of the biggest stars in the Milky Way galaxy capture our attention long after burning out. Considered in this light, Middlebury College physics professor Frank Winkler is a sort of interplanetary paparazzo — his research focuses on supernovas, or, as he puts it, “stars that blow up in the atmosphere.”

The colorful fragments that result from such explosions, termed “supernova remnants,” can hover several light years away from Earth. But high-tech telescopes furnish scientists like Winkler with detailed views.

One star in particular, a supernova remnant called “Puppis A,” has always caught Winkler’s eye. Last fall, he and a scientist from the National Aeronautics and Space Administration (NASA) published a new paper in a scientific journal proving that the star is moving at a speed of 1000 miles per second — likely one of the fastest star velocities ever recorded. Spokespeople at the Harvard-Smithsonian Center for Astrophysics call the speedy ball of fire a “cosmic cannonball.” Winkler, however, finds that term too “militaristic.”

His protectiveness is understandable, given that he’s been studying Puppis A for more than 20 years. Though Winkler has conducted the bulk of his research from an on-campus lab, he has also gazed at the star through a telescope in Chile. As one of 19 scientists worldwide publishing papers on Puppis, he is granted special viewing privileges at the South American observatory for a few days every year.

On a recent visit with Winkler on the Middlebury College campus, the professor enters his fifth-floor office in McCardell Bicentennial Hall wearing corduroys, a V-neck sweater and thick glasses. In a few weeks, he’ll head to Chile for a semester-long sabbatical of telescopic “observing runs.”

“Everything that we know came from visible light,” Winkler begins, cupping his hands behind his head. But when the world was created 13 million years ago, it was “chemically very boring” — full of hydrogen, that is — and relatively monochromatic.

Today’s atmosphere includes some “more interesting” characters, Winkler says — carbon, oxygen, calcium and iron. Such elements were “cooked up inside stars and then blasted out into space when those stars blew up.” Puppis A, the remnant of one such explosion, was created when a huge star “ended its life,” according to the Harvard-Smithsonian Center for Astrophysics. Winkler surmises that since the original star was approximately 25 times the mass of the sun, its cosmic suicide must have been a “dandy explosion” on par with “a gazillion bowling balls crashing to the floor.”

Winkler first fell for Puppis A in 1985, when he and a fellow scientist discovered that the star, at the tender age of 3700 years, was a “relatively young” supernova remnant. Winkler quietly monitored his obsession — a.k.a. “RX J0822-4300” — throughout the Reagan “Star Wars” years. In the mid-1990s, Winkler and a scientist from NASA’s Goddard Space Flight Center discovered Puppis’ inner core, or “neutron star.”

Fast-forward to November 2007, when he and a different NASA scientist published a new paper in the University of Chicago’s Astrophysical Journal. By comparing observatory data from 1999 and 2005 recorded by the Chandra X-Ray Observatory — a NASA satellite that orbits 200 times higher than the Hubble telescope — the astrophysicists concluded that Puppis A’s neutron star was moving at a speed of over 3 million miles per hour. The Harvard-Smithsonian Center reports that the star, which has already traveled 20 million light years, will eventually “escape” from the Milky Way.

“So far as we know, it’s the speed record for neutron stars,” Winkler says with a grin. What’s more, “optical filaments” from supernova remnants offer a visible record of pre-human evolution. (The optical filaments chart history in a similar way that the rings of an old-growth tree would, except that you can’t run your fingers over them.)

Star science may be wonky, but it sparks the human imagination. Astrophysics “is not going to solve the war on poverty or prevent flooding of New Orleans,” Winkler concedes. But even though “the pure-science bit is a relatively small piece of NASA’s pie,” he adds, images culled from such spacey sources as the Hubble telescope “feed the curiosity of people who occupy the planet.”

Pure science has certainly fed his curiosity. Winkler fondly remembers when Sputnik, the world’s first artificial satellite, was launched on the evening of October 4, 1957, as he was returning from a football game. While attending graduate school at Harvard in the late 1960s, he developed a “casual interest” in astrophysics. He came to Middlebury College to teach in 1969 — the same year Neil Armstrong walked on the moon.

Winkler declares that the intervening decades have been a golden age not just for NASA but for astrophysics in general. In 1973, a major breakthrough in X-ray technology facilitated much of his subsequent star research. And equipment in use today, such as the Chandra observatory that tracks Puppis A, is broadening the astrophysical playing field even further. “Science, like any creative enterprise, is a joyful endeavor,” Winkler says with a smile. “This is a gas; it’s a real kick in the pants.”

Karl Twelker, a Winkler protégé who is currently enrolled in a physics PhD program at Stanford University, hints that his former prof never lost his Sputnik-era zeal. A former teaching assistant for Winkler’s introductory physics class, Twelker recalls the elder man as something of a “showman” in an academic setting. That entailed “yanking tablecloths” and “riding a fire extinguisher full of CO2” to demonstrate scientific concepts such as inertia.

“Frank knows the material really well, but he enjoys sharing it with students who aren’t willing to dig into it as deeply as he is,” explains Twelker, one of about 10 students who have accompanied Winkler to Chile over the years. “It’s really impressed me, and I see myself following in his footsteps.”

Not all of Winkler’s charges express such boundless enthusiasm for astrophysics, but that’s probably a good thing. The professor chose small, 2350-student Middlebury College over a big university in part because he enjoys interacting with students who aren’t headed for careers in the hard sciences. “Even though I get older every year, the students don’t,” notes Winkler, who is 65. “There’s always new and fresh ideas coming in. And it keeps you honest.”

Another thing that’s always changing? College facilities. An hour after meeting with a reporter, Winkler leads the way up to the sixth floor of Bicentennial Hall, where a staircase opens onto a closet-sized entryway. An infrared bulb illuminates the narrow space. That helps your eyes adjust to the dark, Winkler says as he turns a door handle.

In the next room, which is unheated, a string of red lights leads the way up another set of stairs. At the top lies a gleaming white telescope. Above that, a retractable, circular ceiling is poised to reveal the starry firmament. The 8-year-old observatory is the largest in Vermont.

“This is the telescope . . . the primary mirror is about here . . . it’s 24 inches in diameter,” Winkler explains while tweaking a lever. An eyehole affords curious visitors a glimpse into the heavens on clear nights. A digital camera takes pictures and feeds them into a nearby computer laboratory.

But even the shiniest gadget is just an expensive extension of our cognitive faculties. Winkler explains that the last Milky Way supernova before Puppis A was observed in 1604, five years before Galileo used a telescope to discover craters of the Earth’s moon and the moons of Jupiter.

Before he descends the stairs, Winkler glances at the telescope and offers a non-technical analogy: “It’s basically a light bucket that collects light in that big eye and focuses it in yours.”