1. Max Mutchler Space Telescope Science Institute Baltimore, Maryland Hubble Science Briefing 6 February 2014 Hubble Observations of Main Belt Comets or “Active Asteroids” The Extraordinary Multi-tailed Main-belt Comet P/2013 P5 Jewitt, DavidJewitt, David; Agarwal, Jessica; Weaver, Harold; Mutchler, Max; Larson, StephenAgarwal, JessicaWeaver, Harold Mutchler, MaxLarson, Stephen The Astrophysical Journal Letters, Vol. 778, Issue 1 (2013)

2. Overview This is not our parents asteroid belt! And not the one of movies and video games either… The asteroid belt is more dynamic than imagined a generation ago –Main Belt Comets –A bigger role in the mystery of Earth’s oceans? Related discoveries: Ceres, Europa water vapor 2

3. Asteroids: typically rocky, with circular orbits between Mars and Jupiter… Main Asteroid Belt 3

4. Comets: typically a mixture of ices and rock, with elliptical orbits extending to the outer Solar System Main Asteroid Belt Comet orbit 4

5. Video about Main Belt Comets with Star Wars clip! http://www.youtube.com/watch?v=qchvgRUDUzA 5

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7. Citation from IAU Minor Planet Circular 56612 on the naming of Asteroid “6815 Mutchler” 7

8. Asteroid history and mystery Ceres, Vesta, Pallas, discovered in early 1800s Called planets for 50 years, then re-classified: any déjà vu ? Key to understanding Solar System formation …and us Giveth: our oceans? Taketh away: Killed the dinosaurs? Still a threat? Exploration with Hubble, Dawn…and astronauts? 8

9. 9 Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI) Star (and planetary system) formation in the Carina Nebula – see the jets?

10. 10 Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI) Star (and planetary system) formation in the Carina Nebula – see the jets?

11. 11 Artists impression of a protostar forming: asteroids are leftover planetesimals from this era – the beginning of the Solar System Credit: NASA/JPL-Caltech/R. Hurt (SSC)

12. 12 Most of the debris left over from planet-building was ejected from the Solar System Credit: NASA

13. Simulation showing the outer planets and planetesimal belt: a)early configuration, before Jupiter and Saturn reach a 2:1 resonance Neptune b)scattering of planetesimals into the inner Solar System after the orbital shift of Neptune and Uranus c)after ejection of planetesimals by planets. 13 a) c)b) The “Nice Model” for the dynamical history of the Solar System R. Gomes, Hal Levison, Alessandro Morbidelli and Kleomenis Tsiganis, 2005, Nature, 435

14. Late Heavy Bombardment 14 Image Credit: Julian Baum

15. 15 Image credit: Don Davis / NASA After the Earth cooled off, later asteroid and comet impacts may have delivered water and organic material to Earth – the stuff of life. Image credit: Don Davis / NASA

16. But does the water add up? http://ga.water.usgs.gov/edu/earthhowmuch.html 16 Credit: Howard Perlman, USGS; globe illustration by Jack Cook, Woods Hole Oceanographic Institution (©); Adam Nieman.

17. Water Ice Discovered on Asteroid for First Time By Clara Moskowitz SPACE.com Senior Writer 28 April 2010 Water ice has been found on the surface of a nearby asteroid for the first time – a discovery that could help explain how Earth got its oceans. Two teams of researchers independently verified that the asteroid 24 Themis – a large rock hurtling through space in the asteroid belt between Mars and Jupiter – is coated in a layer of frost. They also found that the asteroid contains organic material, including some molecules that might be ingredients for life. The discovery might even provide clues about the origin of water on Earth. “Our data are certainly at least consistent with the idea that you could bring in plenty of water from impacts”, said Andrew Rivkin of Johns Hopkins University. 17

18. 18 A comet in the asteroid belt? Nope!

19. “A recent disruption of the main-belt asteroid P/2010 A2” David Jewitt, Harold Weaver, Jessica Agarwal, Max Mutchler & Michal Drahus Nature, Volume 467, 14 October 2010 http://hubblesite.org/newscenter/archive/releases/2010/34/ 19 Images Credit: NASA, ESA, and D. Jewitt (UCLA)

20. Illustration by Ann Feild, STScI 20

21. Research by William F. Bottke, David Vokrouhlicky and David Nesvorny suggests that the impactor believed to have wiped out the dinosaurs and other life forms on Earth 65 million years ago can been traced back to a breakup event in the main asteroid belt. 21

22. Asteroid Scheila: a “Main Belt Comet” ? In the wee hours of December 11, 2010, University of Arizona astronomer Steve Larson was on cosmic patrol with the Catalina Sky Survey's Schmidt telescope. That's when he noticed something odd about the appearance of the main-belt asteroid 596 Scheila. The asteroid was clearly fuzzy, with a soft glow extending a few arcminutes to the west and north. Other astronomers quickly confirmed the cometary appearance. If Scheila is truly a long- dormant comet, then it's a big one: current estimates put its diameter at 70 miles (113 km). "It's a main-belt comet, although I don't know what type yet," Dave Jewitt explains. He says it could have resulted from an impact (as occurred earlier this year with P/2010 A2) or outgassing (as occurs on 133P/Elst-Pizarro). 22 Credit: S. Larson and A. Gibbs (University of Arizona/Catalina Sky Survey) http://www.skyandtelescope.com/news/112140939.html

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24. http://hubblesite.org/newscenter/archive/releases/2011/13/ 24 Artists’s impression of a smaller asteroid colliding with much bigger asteroid Scheila: not all collisions were billions of years ago!

25. “different causes for different objects: impacts, rotational breakup, and sublimation” Asteroids, Comets, Meteors 2012, Niigata, Japan. LPI No. 1667, id.6152 25

26. 26

27. http://hubblesite.org/newscenter/archive/releases/2013/52/ 27

28. The YORP effect: solar radiation spinning up irregularly-shaped small asteroids, and causing mass loss for the “rubble piles”? 28

29. 29 Artist’s impression: Herschel detects water vapor emanating from Ceres! http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_discovers_water_vapour_around_dwarf_planet_Ceres

30. 30 Artist’s impression: Herschel detects water vapor emanating from Ceres! http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_discovers_water_vapour_around_dwarf_planet_Ceres

31. Google hangout about Hubble observations of Vesta and Ceres for the Dawn mission: http://dawn.jpl.nasa.gov/dawncommunity/Google_hangout_12_05_2013.asp 31

32. dwarf planet asteroid (small solar system body) Google hangout about Hubble observations of Vesta and Ceres for the Dawn mission: http://dawn.jpl.nasa.gov/dawncommunity/Google_hangout_12_05_2013.asp 32

33. Why does roundness matter ? Mars 33 Image credits: Gaspra, Ida: Galileo (NASA/JPL); Vesta and Mars images: HST (NASA/STScI); Eros: NEAR Shoemaker (JHU/APL)

34. Why does roundness matter ? 34 Computer model: Credit: NASA/ESANASA, ESA, and A. Feild (STScI) Vesta’s impact crater

35. Dawn Vesta 2011 Ceres 2015 35 Image: William K. Hartmann Courtesy of UCLA

36. 36 This graphic shows the location of water vapor detected over Europa's south pole that provides the first strong evidence of water plumes erupting off Europa's surface. Hubble didn't photograph plumes, but spectroscopically detected auroral emissions from oxygen and hydrogen. The aurora is powered by Jupiter's magnetic field. The image of Europa is derived from a global surface map generated from Voyager and Galileo observations. Science Credit: NASA, ESA, L. Roth (Southwest Research Institute and University of Cologne, Germany), J. Saur (University of Cologne, Germany), K. Retherford (Southwest Research Institute), D. Strobel and P. Feldman (Johns Hopkins University), M. McGrath (Marshall Space Flight Center), and F. Nimmo (University of California, Santa Cruz) NASA/ESA/L. Roth (Southwest Research Institute and University of Cologne, Germany)

37. This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the Sun. Hubble Space Telescope spectroscopic measurements lead scientists to calculate that the plume rises to an altitude of 125 miles and then probably rains frost back onto the moon's surface. Previous findings already point to a subsurface ocean under Europa's icy crust. Artwork Credit: NASA, ESA, and K. Retherford (Southwest Research Institute) 37

38. This is an artist's concept of a plume of water vapor thought to be ejected off of the frigid, icy surface of the Jovian moon Europa, located 500 million miles from the Sun. Hubble Space Telescope spectroscopic measurements lead scientists to calculate that the plume rises to an altitude of 125 miles and then probably rains frost back onto the moon's surface. Previous findings already point to a subsurface ocean under Europa's icy crust. 38 Artwork Credit: NASA, ESA, and K. Retherford (Southwest Research Institute) … fish added by Max!

39. Hubble observations of Main Belt Comets or "active asteroids Hubble observations of Main Belt Comets or "active asteroids" Since 2010, a series of Hubble observations has been conducted to help characterize a recently discovered class of Solar System objects known as Main Belt Comets. These objects can be more accurately described as “active asteroids” -- they have circular orbits in the Main Asteroid Belt, but they appear to exhibit comet-like activity. A recent observation revealed an asteroid sprouting six tails! Along with discoveries of frosty asteroids, and water vapor emanating from the largest asteroid Ceres, there is the tantalizing possibility that Main Belt Asteroids can help explain how Earth's oceans formed. Max Mutchler has been working on the entire Hubble mission -- almost 24 years -- and is currently the head of the Research and Instrument Analysis Branch at the Space Telescope Science Institute. Max is an expert on Hubble’s cameras, and has been involved in a wide range of scientific observations with them. As a member of the Hubble Heritage team, he has helped produce many of the iconic images that Hubble is famous for. In particular, Max loves the challenge of observing Solar System objects with Hubble. He is a member of the team that has discovered four moons of Pluto in support of the New Horizons mission, and he has also worked with the Dawn mission to observe Vesta and Ceres with Hubble. Hubble press release and Google Hangout with Dave Jewitt covering 6-tailed asteroid “P5”: http://hubblesite.org/newscenter/archive/releases/2013/52/ http://www.youtube.com/watch?v=CGgRNWUFfZ0 39