Free Astronomy Magazine July-August 2016

SPACE CHRONICLES Makemake is one of five dwarf planets rec- ognized by the Inter- national Astronomical Union. The observa- tions were made in April 2015 with Hub- ble's Wide Field Cam- era 3. Hubble's unique ability to see faint ob- jects near bright ones, together with its sharp resolution, allowed as- tronomers to pluck out the moon from Make- make's glare. The ob- serving team used the same Hubble tech- nique to observe the moon as they did for finding the small satel- lites of Pluto in 2005, 2011, and 2012. Sev- eral previous searches around Makemake had turned up empty. “Our preliminary esti- mates show that the moon's orbit seems to be edge-on, and that means that often when you look at the system you are going to miss the moon because it gets lost in the bright glare of Makemake,” said Alex Parker of the Southwest Research Institute, Boul- der, Colorado, who led the image Hubble discovers moon orbiting the dwarf planet Makemake P eering to the out- skirts of our solar system, NASA's Hubble Space Tele- scope has spotted a small, dark moon or- biting Makemake, the second brightest icy dwarf planet — after Pluto — in the Kuiper Belt. The moon — pro- visionally designated S/2015 (136472) 1 and nicknamed MK 2 — is more than 1,300 times fainter than Make- make. MK 2 was seen approximately 13,000 miles from the dwarf planet, and its diame- ter is estimated to be 100 miles across. Makemake is 870 miles wide. The dwarf plan- et, discovered in 2005, is named after a crea- tion deity of the Rapa Nui people of Easter Is- land. The Kuiper Belt is a vast reservoir of left- over frozen material from the construction of our solar system 4.5 billion years ago and home to several dwarf planets. Some of these worlds have known satel- by NASA T his artist's concept shows the distant dwarf planet Makemake and its newly discovered moon. Makemake and its moon, nick- named MK 2, are more than 50 times farther away than Earth is from the sun. The pair resides in the Kuiper Belt, a vast reservoir of left- over frozen material from the construction of our solar system 4.5 billion years ago. Makemake is covered in bright, frozen methane that is tinted red by the presence of complex organic material. Its moon is too small to retain ices as volatile as methane, even given the feeble heating by the very distant Sun, and likely has a much dark- er surface. MK 2 is orbiting 13,000 miles from the dwarf planet, and its estimated diameter is roughly 100 miles across. Makemake is 870 miles wide. [NASA, ESA, and A. Parker (Southwest Research Institute)] lites, but this is the first discovery of a companion object to Makemake.