Free Astronomy Magazine September-October 2016

52 SEPTEMBER-OCTOBER 2016 SPACE CHRONICLES et ,” said Trevor David, first author of the study and a graduate stu- dent working with professor of astronomy Lynne Hillenbrand. “The high resolution spectra were also used to confirm the youth of the star, measure its tempera- ture and how fast it is rotat- ing, and rule out the pres- ence of any additional stars in the system.” High resolution images obtain- ed with Keck Observato- ry’s NIRC2 instrument in 2011 and 2016 were also used to con- firm that there were no other nearby stars (either grav- itationally bound to K2-33, or in the back- ground but aligned by chance) that might bemim- icking a planet transit signal. By comparison, the new discovery is a new born. “At 4.5 billion years old, the Earth is a middle- aged planet — about 45 in human-years,” Da- vid said. “The planet K2-33b would be an in- fant of only a few weeks old.” “This discovery is a remarkable mile- stone in exoplanet science,” added Discovered: youngest ful exoplanet ever by Keck Observatory A team of Caltech-led re- searchers discovered the youngest fully-formed exo- planet ever detected using the W. M. Keck Observatory on Mauna Kea, Hawaii and the Kepler Space Telescope. The planet, K2-33b, at five to 10 million years old, is still in its in- fancy. Planet formation is a complex and tumultuous process that remains shrouded in mystery. Astronomers have discovered roughly 2,000 plan- ets orbiting stars other than our Sun — however, nearly all are middle- aged, with ages of a billion years or more. For astronomers, attempting to understand the life cycles of plan- etary systems using existing ex- amples is like trying to learn how people grow from babies to chil- dren to teenagers, by only studying adults. The first signals of the plan- et's existence were measured by NA- SA's Kepler space telescope during its K2 mission. The telescope detect- ed a periodic dimming in the light emitted by the planet's host star, K2- 33, that hinted at the existence of an orbiting planet. Observations from the W. M. Keck Observatory in Ha- waii validated that the dimming was indeed caused by a planet, using both of the 10 meter Keck tele- scopes: the HIRES instrument instal- led on Keck I and NIRC2 on the Keck II. “HIRES was used to measure the Doppler shift (radial velocity) of the star over time, and confirm that the orbiting companion is a plan-