1 / 15

Physics 320: Astronomy and Astrophysics – Lecture XIV

Physics 320: Astronomy and Astrophysics – Lecture XIV. Carsten Denker Physics Department Center for Solar–Terrestrial Research. Pluto, Solar System Debris, and Formation. The Pluto-Charon System Comets Asteroids Meteorites The Formation of the Solar System.

naiya
Download Presentation

Physics 320: Astronomy and Astrophysics – Lecture XIV

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physics 320: Astronomy and Astrophysics – Lecture XIV Carsten Denker Physics Department Center for Solar–Terrestrial Research

  2. Pluto, Solar System Debris, and Formation • The Pluto-Charon System • Comets • Asteroids • Meteorites • The Formation of the Solar System NJIT Center for Solar-Terrestrial Research

  3. Pluto discovered by Clyde W. Tombaugh in 1930 (15th magnitude) 248.5 yr orbital period Eccentricity 0.25 29.7 AU perihelion (closer than Neptune) 49.3 AU aphelion 17° inclination to ecliptic 3-2 orbital resonance with Neptune (no danger of collsions) Radius 1160 km Its moon Charon discovered in 1978 Orbit around common center of mass in 6.4 d Separation 19640 km (1/20 Earth-Moon distance) Reduced mass is 0.24% mass of Earth MCharon / MPluto = 0.09 to 0.16 Orbital plane of Pluto-Charon system is inclined 122.5° with respect to their orbit around the Sun The Pluto-Charon System NJIT Center for Solar-Terrestrial Research

  4. Pluto Pluto is mostly brown. No spacecraft has yet visited this most distant planet in our Solar System. The map was created by tracking brightness changes from Earth of Pluto during times when it was being partially eclipsed by its moon Charon. Pluto's brown color is thought dominated by frozen methane deposits metamorphosed by faint but energetic sunlight. NJIT Center for Solar-Terrestrial Research

  5. Pluto-Charon Pluto is the only planet in our Solar System remaining unphotographed by a passing spacecraft. These maps depict the face of Pluto (left) that always faces Charon, and the face of Charon that always faces away from Pluto. The Pluto-Kuiper Express mission is tentatively planned for launch in 2004 and might encounter Pluto as early as 2012. NJIT Center for Solar-Terrestrial Research

  6. Halley’s comet (observed since 240 B.C., 76 yr orbital period) Nucleus: “dirty snowball” or “snowy dirtball”? Size:  10 km Coma: cloud of gas and dust, sublimated ice Interaction with sunlight and solar wind creates dust (radiation pressure) and ion (magnetic field) tail up to 1 AU length A hydrogen gas halo envelopes the coma Tails are always directed away from the Sun (ion trails are straight, dust tails are curved) Dust grains scatter light, tail appears white/yellow Blue ion tail: CO+ ions absorb UV radiation and reradiate at 420 nm Composition: 80% H2O, 10% CO, 3.5% CO2, few % (H2CO)n, 1% CH3OH Comets NJIT Center for Solar-Terrestrial Research

  7. Disconnection events Water on terrestrial planets from comet impacts? Halley: Suisei, Sakigake, Vega 1/2, Giotto (closest approach 600 km), Cometary Explorer Halley’s size 15 km  7.2 km  7.2 km Mass: 5  1013 kg to 1014 kg Halley is a short-period comet < 200yr (Kuiper belt objects 30 AU to 100 AU) Long-period comets 100,000 to 1 million yr Long-period comets originate in the Oort cloud Inner cloud in ecliptic 3,000 AU to 20,000 AU Outer cloud has spherical distribution 20,000 AU to 100,000 AU Planetesimals “catapulted” from Jovian planets to Oort cloud Random motion Comets (cont.) NJIT Center for Solar-Terrestrial Research

  8. Dust Tail R < Rcrit: net outward force, spiral away from Sun R > Rcrit: continue to orbit Sun (Poynting-Robertson effect!) NJIT Center for Solar-Terrestrial Research

  9. Hale-Bopp NJIT Center for Solar-Terrestrial Research

  10. Halley’s Comet NJIT Center for Solar-Terrestrial Research

  11. Sungrazer (SoHO/LASCO) NJIT Center for Solar-Terrestrial Research

  12. Minor planets mostly between Mars and Jupiter Discovery of Ceres in 1801 by Piazzi Combined mass of all asteroids 5 104M Orbital resonances with Jupiter Kirkwood gaps Trojan asteroids (1:1 resonance group, Lagrange points L4 and L5) Hirayama families (originally single asteroid that suffered a catastrophic collision) Collision speeds of up to 5 km/s Composition is a function of the distance from the Sun (volatiles (water) vs. refractory compounds (silicon)) Metal rich asteroids from larger parent asteroids with chemical differentiation Asteroids NJIT Center for Solar-Terrestrial Research

  13. Asteroids (cont.) NJIT Center for Solar-Terrestrial Research

  14. Orbital Resonances and Trojans NJIT Center for Solar-Terrestrial Research

  15. Lagrange Points The Italian-French mathematician Lagrange discovered five special points in the vicinity of two orbiting masses where a third, smaller mass can orbit at a fixed distance from the larger masses. The Lagrange Points mark positions where the gravitational pull of two large masses precisely equals the centripetal force required to rotate with them. NJIT Center for Solar-Terrestrial Research

More Related