My first Magazine Sky & Telescope - 03.2019 | Page 6

SPECTRUM by Peter Tyson Super Stars The Essential Guide to Astronomy Founded in 1941 by Charles A. Federer, Jr. and Helen Spence Federer WITH THIS ISSUE we kick off a three- Editor in Chief Editorial Correspondence (including permissions, partnerships, and content licensing): Sky & Telescope, 90 Sherman St., Cambridge, MA 02140-3264, USA. Phone: [phone]. E-mail: [email protected]. Website: skyandtelescope.com. Unsolicited proposals, manuscripts, photographs, and electronic images are welcome, but a stamped, self-addressed envelope must be provided to guarantee their return; see our guidelines for contributors at skyandtelescope.com. 4 Advertising Information: Tim Allen 773-551-0397, Fax: [phone]. E-mail: [email protected] Web: skyandtelescope.com/advertising Customer Service: Magazine customer service and change-of-address notices: [email protected] Phone toll-free U.S. and Canada: 800-253-0245. Outside the U.S. and Canada: 386-597-4387. M A RCH 2 019 • SK Y & TELESCOPE EDITORIAL Editor in Chief Peter Tyson Senior Editor Alan M. MacRobert Science Editor Camille M. Carlisle News Editor Monica Young Associate Editors S. N. Johnson-Roehr, Sean Walker Observing Editor Diana Hannikainen Project Coordinator Bud Sadler Digital Content Strategist Janine Myszka Senior Contributing Editors J. Kelly Beatty, Robert Naeye, Roger W. Sinnott Contributing Editors Howard Banich, Jim Bell, Trudy Bell, John E. Bortle, Greg Bryant, Thomas A. Dobbins, Alan Dyer, Tom Field, Tony Flanders, Ted Forte, Sue French, Steve Gottlieb, David Grinspoon, Shannon Hall, Ken Hewitt-White, Johnny Horne, Bob King, Emily Lakdawalla, Rod Mollise, James Mullaney, Donald W. Olson, Jerry Oltion, Joe Rao, Dean Regas, Fred Schaaf, Govert Schilling, William Sheehan, Mike Simmons, Mathew Wedel, Alan Whitman, Charles A. Wood Contributing Photographers P. K. Chen, Akira Fujii, Robert Gendler, Babak Tafreshi ART & DESIGN Art Director Terri Dubé Illustration Director Gregg Dinderman Illustrator Leah Tiscione ADVERTISING VP, Advertising Sales Kevin D. Smith Advertising Sales Director Tim Allen Advertising Coordinator Connie Kostrzewa part series on famous stars: Polaris, Alpha Centauri, and Betelgeuse. Why did we choose these three over the thousands of others visible to the naked eye? Each holds abiding fascination not only Artist’s concept of the three-star for astronomers, both amateur and professional, but Polaris system also for a broad swath of the enthusiastic public. Each is iconic in its own way. And each provides a keyhole glimpse into different sec- tors of cutting-edge science, from the formation of planets to how stars explode. Our first subject, Polaris, easily fits the bill. It’s readily visible to observers in the Northern Hemisphere, even in light-polluted skies. A fixture of star- party outreach, it plays a fundamental role in familiarizing beginners with the constellations. (“See those two stars on the outer edge of the Big Dipper’s bowl? They point to Polaris.”) Owners of equatorial mounts generally rely on the North Star to align their telescopes, and astrophotographers cherish it as a centerpiece in their star-trails photos — just see our cover. But Polaris’s fame reaches beyond astronomy and into history and culture. Generations of seafarers knew that the star indicates the direction to true north, while its height in the heavens gives an idea of latitude. Our very notion of the “lodestar,” a guiding principle or person, arose from the navigational utility of the North Star. Polaris became a lasting symbol of steadfastness: “I am constant as the northern star,” boasts Shakespeare’s Julius Caesar, “Of whose true-fixed and resting quality / There is no fellow in the firmament.” The irony, as Camille Carlisle notes in our cover story starting on page 14, is that “there is almost nothing constant about the North Star.” Polaris is the nearest and brightest Cepheid variable, those exquisitely precise pulsating stars that serve as benchmarks for judging astronomical distances. Yet because of quirks in its pulsation, Polaris is useless for this. Recently astronomers discov- ered that the star emits X-rays, which it shouldn’t be able to do. Even the pole star’s much-vaunted fixity is an illusion: After March 24th, 2100, the North Star will begin moving away from the north celestial pole and will eventually cease altogether serving as the Northern Hemisphere’s lodestar. Which brings me to the final criterion to be chosen for our series: A star had to have personality. Polaris, that changeless changeling, certainly has it. And each of the two others in our triad — Alpha Centauri (the nearest star system to our own) and the red supergiant Betelgeuse (many people’s favorite supernova progenitor) — has its own distinct charisma. But you’ll have to wait till the April and May issues, respectively, to get the skinny on them. F+W MEDIA Chief Executive Offi cer Gregory J. Osberg Chief Financial Offi cer Kenneth Kharbanda SVP / GM — F+W Fine Art, Writing, Outdoors & Small Business Group Ray Chelstowski Managing Director — F+W International James Woollam VP, Consumer Marketing John Phelan VP, General Counsel Robert Sporn VP, Product Management Pat Fitzgerald Newsstand Sales Scott T. Hill, [email protected] Visit shopatsky.com Shop at Sky customer service: [email protected] 888-253-0230. Outside the U.S. and Canada: 970-658-2929. 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