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SECRETS EXOPLANETS REVEAL White Dwarf Stars Shed New Light on Possible Life-Bearing Planets P EXPLORE JUPITER’S TROJAN ASTEROIDS UP CLOSE p. 28 JUNE 2018 The world’s best-selling astronomy magazine NEW RESEARCH SECRETS EXOPLANETS REVEAL White dwarf stars shed new light on possible life-bearing planets p. 22 DISCOVER GALAXIES in Coma Berenices p. 52 BEHIND THE SCENES at Chicago’s great astro sites p. 44 IMAGING for three nights www.Astronomy.com at Pic du Midi p. 58 BONUS Vol. 46 FIELDTESTED ONLINE • ONLINE Issue 6 A hot new CONTENT CODE p. 4 CCD camera p. 64 The lightweight ProED/Evostar 80 matches perfectly with our AllView mount to make an ideal night-or-day, grab-and-go system. The AllView multi-purpose GoTo mount is designed and intended for a wide variety of applications, such as panoramic and time-lapse photography, daytime viewing, videography and astronomical viewing. 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No homework. Just a world of knowledge THEGREATCOURSES.CO/6ASTR available anytime, anywhere. Download or stream to your laptop or PC, or use our free apps for iPad, iPhone, Android, Kindle Fire, or 1-800-832-2412 Roku. Over 600 courses available at www.TheGreatCourses.com. Online Content Code: ASY1806 Enter this code at: www.astronomy.com/code JUNE 2018 to gain access to web-exclusive content VOL. 46, NO. 6 MARK GARLICK MARK ON THE COVER Astronomers are finding watery worlds orbiting stars around us — and the way some of those worlds get their water is surprising. 28 COLUMNS Strange Universe 14 CONTENTS BOB BERMAN FEATURES Observing Basics 16 GLENN CHAPLE 22 COVER STORY 38 58 For Your Consideration 18 Water worlds in the StarDome and Three nights at JEFF HESTER Milky Way Path of the Planets Pic du Midi How do planets get their water? 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