1 / 33

LECTURE 13, OCTOBER 7, 2010

LECTURE 13, OCTOBER 7, 2010. ASTR 101, SECTION 3 INSTRUCTOR, JACK BRANDT jcbrandt@unm.edu. HALLEY’S COMET. First comet to have its return predicted. Occurred in 1759 AD, a triumph of celestial mechanics Seen at nearly every apparition since 239 BC Returns on average every 76 years

errol
Download Presentation

LECTURE 13, OCTOBER 7, 2010

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. LECTURE 13, OCTOBER 7, 2010 ASTR 101, SECTION 3 INSTRUCTOR, JACK BRANDT jcbrandt@unm.edu ASTR 101-3, FALL 2010

  2. ASTR 101-3, FALL 2010

  3. ASTR 101-3, FALL 2010

  4. ASTR 101-3, FALL 2010

  5. HALLEY’S COMET • First comet to have its return predicted. Occurred in 1759 AD, a triumph of celestial mechanics • Seen at nearly every apparition since 239 BC • Returns on average every 76 years • Last return was in 1986 AD & 5 spacecraft were sent to its vicinity • Next return is in 2061 AD ASTR 101-3, FALL 2010

  6. ASTR 101-3, FALL 2010

  7. ASTR 101-3, FALL 2010

  8. ASTR 101-3, FALL 2010

  9. ASTR 101-3, FALL 2010

  10. ASTR 101-3, FALL 2010

  11. PROCESSES IN COMETS-1 • The basic process is sublimation, the direct transition from solid water ice to vapor • Produces water vapor and releases dust particles and other gases trapped in the ice • All cometary phenomena ultimately originate with material in the nucleus • Energy source is solar radiation as the nucleus approaches the sun ASTR 101-3, FALL 2010

  12. PROCESSES IN COMETS-2 • Gas and dust emission comes from localized areas on the surface of the nucleus • After sublimation occurs from the surface layers, a loose, dust crust remains. Confirmed by Deep Impact • Dust and gas (atoms & molecules) flow outward to form the coma and hydrogen cloud ASTR 101-3, FALL 2010

  13. PROCESSES IN COMETS-3 • Solar radiation pressure pushes dust particles anti-sunward to make the dust tail • Some molecules are ionized (electrically charged) and are carried anti-sunward by the solar wind to form the ion/plasma tail ASTR 101-3, FALL 2010

  14. TEXT PROBLEM, PAGE 111, ETC. • The text statement: “Both types of tails are in all cases directed away from the Sun by the solar wind, an invisible steam of matter and radiation of escaping from the Sun.” • This is wrong. See previous slide. Also, the solar wind is composed of particles and magnetic fields, but not radiation. ASTR 101-3, FALL 2010

  15. ASTR 101-3, FALL 2010

  16. ASTR 101-3, FALL 2010

  17. Question 9 • their densities are higher. • their orbits tend to be more elliptical. • they tend to be made of ice. • they can look fuzzy, whereas asteroids appear as moving points of light. • their average distances from the Sun are far greater. Compared to asteroids, comets show all of these properties EXCEPT ASTR 101-3, FALL 2010

  18. Question 9 • their densities are higher. • their orbits tend to be more elliptical. • they tend to be made of ice. • they can look fuzzy, whereas asteroids appear as moving points of light. • their average distances from the Sun are far greater. Compared to asteroids, comets show all of these properties EXCEPT Comets have densities much lower than asteroids or planets. ASTR 101-3, FALL 2010

  19. DISCONNECTION EVENTS • Occasionally, the entire ion/plasma tail disconnects from the head region • A new ion/plasma tail is formed • Produced by a specific feature in the solar wind ASTR 101-3, FALL 2010

  20. ASTR 101-3, FALL 2010

  21. ASTR 101-3, FALL 2010

  22. ASTR 101-3, FALL 2010

  23. ASTR 101-3, FALL 2010

  24. ASTR 101-3, FALL 2010

  25. ASTR 101-3, FALL 2010

  26. Question 10 a) A comet and an asteroid collide. b) Earth runs into a stray swarm of asteroids. c) Earth runs into the debris of an old comet littering its orbit. d) Meteorites are ejected from the Moon. e) Debris from a supernova enters Earth’s atmosphere What causes a meteor shower? ASTR 101-3, FALL 2010

  27. Question 10 a) A comet and an asteroid collide. b) Earth runs into a stray swarm of asteroids. c) Earth runs into the debris of an old comet littering its orbit. d) Meteorites are ejected from the Moon. e) Debris from a supernova enters Earth’s atmosphere What causes a meteor shower? Meteor showers can generate a few shooting stars, to hundreds of thousands, seen in an hour. ASTR 101-3, FALL 2010

  28. ASTR 101-3, FALL 2010

  29. ASTR 101-3, FALL 2010

  30. ASTR 101-3, FALL 2010

  31. Question 12 a) a cold terrestrial planet. b) a small jovian planet. c) a large Kuiper belt object. d) a wandering moon. e) a captured comet. Many astronomers believe Pluto is perhaps best classified as ASTR 101-3, FALL 2010

  32. Question 12 a) a cold terrestrial planet. b) a small jovian planet. c) a large Kuiper belt object. d) a wandering moon. e) a captured comet. Many astronomers believe Pluto is perhaps best classified as Several other large Kuiper belt objects have been discovered, including the largest known, called Eris. ASTR 101-3, FALL 2010

  33. ASTR 101-3, FALL 2010

More Related