AST 301, Debris Lecture James Lattimer Department of Physics & Astronomy 449 ESS Bldg. Stony Brook University February 26, 2019 Cosmic Catastrophes [email protected] James Lattimer AST 301, Debris Lecture Debris in the Solar System: Comets Hale-Bopp I \Dirty snowballs", a mixture of ices and dust, ejected from solar system when planets formed I Mass mostly contained in a nucleus (solid dirty snowball) with km-sized diameter Hally's nucleus I Coma, a cloud of H2O, CO2 and other gases va- porized from nucleus during close passage to Sun from Giotto I Hydrogen cloud, huge but sparse neutral H cloud I Dust tail, 1{10 million km long, dust driven off nucleus by escaping gases when close to Sun I Ion tail, 100's of millions of km long, plasma driven off by solar wind I Most comets reside far outside the orbit of Pluto, a few occasionally perturbed into close-solar orbits; some are in elliptical orbits and reappear I After a few hundred passages near the Sun, icy material is lost, Shoemaker-Levy 9 before Jupiter impact leaves dead comet which can be mis- taken for asteroid. James Lattimer AST 301, Debris Lecture Comet Holmes, Halloween, 2007 V. Peris and J. L. Lamadrid Fragment G HST 7/18/1994 Shoemaker-Levy 9 HST 7/7/1994 James Lattimer AST 301, Debris Lecture Comets History I Records of comets exist at least to 1140 BC I Brahe observed comet of 1577, proved they are extraterrestrial I Halley: some comets are periodic (1531, 1607, 1682) I Halley's Comet: 2467 BC (?), 240 BC (China), 1066 (Bayeux Tapestry) I Motivated Newton to develop gravity theory Orbits I Hyperbolic: pass Sun once, depart forever I Elliptical: periodic I Peri-/Aphelion: closest/farthest solar approach Origin I Short-period come from Kuiper Belt, 35,000 icy bodies larger than 100 km, 30-100 AU I Long-period come from Oort comet cloud, ∼ 1012 comets, 30,000 AU{1 lt. yr. I Most formed within inner solar system, then pushed outwards by repeated near encounters James Lattimer AST 301, Debris Lecture Giotto's Adoration of the Magi From 1301 appearance James Lattimer AST 301, Debris Lecture Missions to Comets I International Cometary Explorer (ICE), August 1978, Comet Giacobini-Zinner (Sept. 1985), Comet Halley (Mar. 1986) I Vega-1 and Vega-2, December 1984, left landers on Venus, Comet Halley (Mar. 1986) I Sakigake and Suisei, January 1985, Comet Halley (Mar. 1986) I Giotto, July 1985, Comet Halley (Mar. 1986), Comet Grigg-Skjellerup (Jul. 1992) I Deep Space 1, October 1998, asteroid 9969 Braille (Jul. 1999), Comet Borrelly (Sep. 2001) I Stardust, February 1999, Comet Wild 2 (Jan. 2004, returned dust particles to Earth in 2006), Comet Tempel (2011) I Contour, July 2002, lost. I Deep Impact, January 2005, Comet Tempel 1 (also impactor), Comet Hartley 2 (Nov. 2010), Comet Garradd (Feb.-Apr. 2012), Comet ISON (Jan. 2013) I Rosetta, March 2004, asteroids 2867 Steins (2008) and 21 Lutetia (2010), Comet 67P/Churyumov-Gerasimenko (Aug. 2014) James Lattimer AST 301, Debris Lecture Halley's Comet and Giotto Size is 15 × 8 × 8 km. Density is very small, 0.3 g cm−3. Water, CO and CO2 were 80%, 10% and 2.5% of matter ejected. Traces of hydrocarbons, iron, sodium observed. Abundances of light elements (except N) are same as in Sun. Albedo blacker than coal. Jets threw out 3 tons/s. James Lattimer AST 301, Debris Lecture Comet Shoemaker-Levy 9 I This comet was discovered by Eugene and Carolyn Shoemaker and David Levy on March 18, 1993. I The comet may have been captured by Jupiter in 1966. I The comet apparently broke apart due to tidal forces on July 7, 1992 on a close approach 25,000 to 120,000 km away. I The comet's original size was about 1.5 to 2 km in diameter. I The comet fragments crashed into Jupiter from 16 to 22 July, 1994. I The total released energy was about 300 Gtons of TNT. I Plumes rose to 3000 km height, and the atmosphere near the impacts was heated to 40,000 K. I Other objects have been seen to impact Jupiter in 2009, 2010 (twice), 2016 and 2017. I The SL-9 homepage was the first major global webpage on www. I The SL-9 impact likely was the trigger for NASA to receive funding for NEO searches. I Comet Schwassmann-Wachmann 3 was observed to brighten in September 1996 and split into 8 or more pieces between October and December 1996. James Lattimer AST 301, Debris Lecture James Lattimer AST 301, Debris Lecture James Lattimer AST 301, Debris Lecture Deep Space 1 I Designed to test a dozen new technologies including an ion engine. I Launched in October 1998, it completed testing the technologies in less than a year. I Made a bonus flyby of 9969 Braille in July 1999, approaching within 17 miles. I While making a new journey to comet Borrelly, star tracker orientation system failed in November 1999. Comet Borrelly I By June 2000, engineers were able to use the on-board camera as a replacement navigational tool. Probably the most successful robotic space rescues in history. I Approached comet Borrelly in September 2001, took best comet pictures up to that time. James Lattimer AST 301, Debris Lecture James Lattimer AST 301, Debris Lecture James Lattimer AST 301, Debris Lecture Stardust I Designed to study comet Wild 2, a comet Annefrank perturbed by Jupiter from a long-period to short-period comet in 1974, in 2004. I Designed to capture comet and interstellar dust with an aerogel collector, and return dust to Earth. Comet Wild 2 I Flyby of asteroid 5535 Annefrank (Nov. 2002) and comet Wild 2 (Sep. 2004), Earth sample return (Jan. 2006), and flyby of comet Tempel 1 (Feb. 2011). I Evidence found for liquid water and the amino acid glycine in comet Wild 2. I Results showed outer regions of solar system were not isolated and were not a refuge of interstellar matter, and matter from the high-temperature inner solar system was mixed into the Kuiper Belt. James Lattimer AST 301, Debris Lecture James Lattimer AST 301, Debris Lecture Comet Tempel 1 and Deep Impact Mission I Discovered April 3, 1867 by Ernst Wilhelm Leberecht Tempel of Marseilles, France. I Recognized as periodic by Bruhns of Leipzig; P = 5:68 years. I In 1881, the comet had a close encounter with Jupiter and its period changed to 6.5 years, and perihelion was increased from 1.8 AU to 2.1 AU. I The comet was subsequently lost, due to close approaches with Jupiter in 1941 and 1953, among others. I Presently, comet is in a 1:2 resonance with Jupiter, P = 5:5 years. James Lattimer AST 301, Debris Lecture Tempel 1 and Deep Impact NASA James Lattimer AST 301, Debris Lecture Tempel 1 and Deep Impact NASA James Lattimer AST 301, Debris Lecture Tempel 1 and Deep Impact T - 3 min. T + 12 min. T + 1 hr. 4 min. HST T + 1 hr. 28 min. T + 4 hr. 41 min. T + 19 hr. 7 min. Comet 9P/Tempel 1 • July 4-5, 2005 Hubble Space Telescope • Advanced Camera for Surveys NASA, ESA, P. Feldman (Johns Hopkins University) and H. Weaver (Johns Hopkins University Applied Physics Laboratory) STScI-PRC05-17c James Lattimer AST 301, Debris Lecture Comet Tempel 1 Impact Site James Lattimer AST 301, Debris Lecture Comet Tempel 1 Deep Impact Recession due to sublimation. Stardust James Lattimer AST 301, Debris Lecture Tempel 1 Findings I It's a fluff ball, about 50/50 rock and water ice grains. I Rock dust consists of silicate grains, like crushed gems, smaller than sand grains. I Clays and carbonates also exist (seashells made from these), which is unexpected because it is thought they need liquid water to form. I This may indicate a more thorough mixing of primordial solar system matter, so that grains formed in liquid water near the Sun are mixed with icy material from out by Uranus and Neptune. water iceH 2O dry iceCO 2 olivine (Mg,Fe)Si2O4 montmorillonite clay (Al, Si, O) polycyclic aromatic hydrocarbons spinel MgAl2O4 iron Fe enstatite MgSiO3 dolomite CaMg(CO3)2 marcasite FeS2 SPACE.com James Lattimer AST 301, Debris Lecture Findings Concerning Comet Hartley-2 I A pebbly trail discovered by WISE = Wide-field Infrared Survey Explorer I Deep Impact found its core does not have a uniform composition: jets spewing ice and CO2 in one direction, and others spewing water vapor but no CO2. I Deep Impact also found three types of ices: H2O with methanol, CO2, and C2H2 (ethane). James Lattimer AST 301, Debris Lecture Comet 67P/Churyumov-Gerasimenko Discovered September 1969 Deflected by Jupiter in 1840 and 1959 Perihelion moved from 4AU to 1.3AU Orbital period is 6.45 yr. Size is 4:3 × 2:5 × 4:1 km Mass is 1016 g Comet 67P/Churyumov-Gerasimenko Albedo is blacker than coal Density is less than water James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Philae James Lattimer AST 301, Debris Lecture Rosetta James Lattimer AST 301, Debris Lecture Gases Detected: Comet 67P/Churyumov-Gerasimenko Water, carbon monoxide, carbon dioxide, ammonia, methane, ethane, propane, butane, pentane, hexane, heptane, formic acid, acetic acid, acetaldehyde, ethylenglycol, propylenglycol, butanamide, methanol, ethanol, propanol, butanol, pentanol, glycine, argon, krypton, xenon, cyanogen, acetylene, hydrogen cyanide, acetonitril, formaldehyde, sodium, potassium, silicon, magnesium, hydrogensulphide, carbonylsulphide, sulphur monoxide, sulphur dioxide, carbon disulphide, nitrogen, oxygen, hydrogenperoxy, benzene, toluene, xylene, benzoic acid, naphthalene, hydrogen fluoride, hydrogen chloride, hydrogen bromide, phosphorus, chloromethane, methylamine, ethylamine, sulphur, disulphur, trisulphur, tetrasulfur, methanethiole (CH3SH), ethanethiol (C2H5SH), thioformaldehyde (CH2S) James Lattimer AST 301, Debris Lecture Asteroids I Also called minor planets or planetoids, largely lying within the orbits of Mars and Jupiter (main asteroid belt).