Dwarf Planet - Makemake

Makemake





                                    Mass                         ~            3 × 1021 kg
                                    Surface gravity           ~            0.37 m/s2
                                                Discovery date           :             March 31, 2005
                                                Discovered by            :             Michael E. Brown
                                                                                   Chad Trujillo
                                                                                   David Rabinowitz
 
 
 (Michael E. Brown)
 
  (Chad Trujillo)
 
(David Rabinowitz)
 
 
                                                       Makemake, minor-planet designation 136472 Makemake, is a dwarf planet and perhaps the largest Kuiper belt object (KBO) in the classical population, with a diameter that is about 2/3 the size of Pluto. Makemake has no known satellites, which makes it unique among the largest KBOs and means that its mass can only be estimated. Its extremely low average temperature, about 30 K (−243.2 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices . Makemake—pronounced MAH-keh MAH-keh after a Polynesian creation god—is one of five Pluto-like objects that prompted a redefining of the term "planet" and the creation of a new group of dwarf planets in 2006.
                                                        After Eris and Pluto, Makemake is the third largest known dwarf planet. Along with fellow dwarf planets Pluto and Haumea, Makemake is located in the Kuiper Belt, a region outside the orbit of Neptune. Pluto and Makemake are the two brightest objects that have so far been discovered in the Kuiper Belt. It takes 310 Earth years for this dwarf planet to make one orbit around the Sun.As of 2009, Makemake is at a distance of 52 astronomical units (7.8×109 km) from the Sun
 
 
 
                                                         Makemake was first observed in 2005 by a team of astronomers led by Michael Brown. Its codename was Easterbunny. It was officially recognized as a dwarf planet by the International Astronomical Union in 2008. Observations have found evidence of frozen nitrogen on Makemake's surface. Frozen ethane and methane have also been detected on the surface. In fact, astronomers believe the methane may actually be present in pellets as large as one centimeter in diameter. Astronomers also found evidence of tholins. Tholins are molecules that form whenever solar ultraviolet light interacts with substances such as ethane and methane. Tholins, if present, usually cause a reddish-brown color. During observations of Makemake, a reddish color was observed.
                                                       Dwarf planet Makemake  is about two thirds of the size of Pluto, and travels around the Sun in a distant path that lies beyond that of Pluto but closer to the Sun than Eris, the most massive known dwarf planet in the Solar System . Previous observations of chilly Makemake have shown it to be similar to its fellow dwarf planets, leading some astronomers to expect its atmosphere, if present, to be similar to that of Pluto. However, the new study now shows that, like Eris, Makemake is not surrounded by a significant atmosphere.The team, led by Jose Luis Ortiz (Instituto de Astrofisica de Andalucia, CSIC, Spain), combined multiple observations using three telescopes at ESO's La Silla and Paranal observing sites in Chile -- the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) -- with data from other small telescopes in South America , to look at Makemake as it passed in front of a distant star ."As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually. This means that the little dwarf planet has no significant atmosphere," says Jose Luis Ortiz. "It was thought that Makemake had a good chance of having developed an atmosphere -- that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies. Finding out about Makemake's properties for the first time is a big step forward in our study of the select club of icy dwarf planets."


                                                    Makemake is currently visually the second-brightest Kuiper belt object after Pluto, having a March opposition apparent magnitude of 16.7 in the constellation Coma Berenices. This is bright enough to be visible using a high-end amateur telescope. Combining the detection in infrared by the Spitzer Space Telescope and Herschel Space Telescope with the similarities of spectrum with Pluto yielded an estimated diameter from 1,360 to 1,480 km. From the 2011 stellar occultation by Makemake, its diameter has been measured to be (1502 ± 45) × (1430 ± 9) km. This is slightly larger than Haumea, making Makemake likely the third largest known trans-Neptunian object after Eris and Pluto. Makemake was the fourth dwarf planet recognized, as it has a bright V-band absolute magnitude of −0.44 that practically guarantees it is large enough to achieve hydrostatic equilibrium.





                            






          

Posted by Unknown | at 22:40

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