Astronomy/Geology 330 Seminar on Asteroids Tuesdays 4-7 pm Kendade Hall 203 Tom Burbine tburbine@mtholyoke

1. Astronomy/Geology 330Seminar on AsteroidsTuesdays 4-7 pmKendade Hall 203Tom Burbinetburbine@mtholyoke.edu

3. Focus of Class • Asteroids • Comets • Meteorites

4. My Background • BS in Physics from RPI • MS in Geology and Planetary Science from the Univ. Pittsburgh • PhD in Planetary Science from MIT • Postdoc at the Smithsonian’s Natural History Museum for 3 years • Postdoc at NASA’s Goddard Space Center for 2 years • Researcher at Mount Holyoke since January • Taught Astronomy 100 at UMASS in Spring

5. Tuesdays in October and November 4-5 pm Kendade Hall 305 Mount Holyoke College Introduction to Planetary Science Seminar Series October 18th – Cometary Volatiles – William Irvine (UMASS) October 25th – Cometary Dust and Nuclei – Martha Hanner (UMASS) November 1st – Minor Planet Center – Timothy Spahr (CFA) November 8th – Asteroid Hazards – Richard Binzel (MIT) November 15th – NEAR-Shoemaker Mission– Louise Prockter (APL) November 29th – Deep Impact– Lucy McFadden (Univ. Maryland) For more information, contact Tom Burbine (tburbine@mtholyoke.edu) Funded by a grant from Mount Holyoke’s Innovation Fund

6. Website • www.mtholyoke.edu/courses/tburbine/ASTR330 • Can be accessed using WebCT • All presentations will be available on website immediately after class • So you don’t have to copy down everything I put up

7. Grading • Class Exercises - 10% • Problem Sets -10% • Class Participation - 10% • Class Presentation - 10% • Mid-Term (October 4th) - 20% • Final - 20% • Final Project- 20% • Late Class Exercises and Problem Sets will have 10% of their grade deducted for every day they are late (unless this is your first class)

8. A 92.50 - 100 • A- 89.50 – 92.49 • B+ 87.50 – 89.49 • B 82.50 – 87.49 • B- 79.50 – 82.49 • C+ 77.50 – 79.49 • C 72.50 – 77.49 • C- 69.50 – 72.49 • D+ 67.50 – 69.49 • D 62.50 – 67.49 • D- 59.50 – 62.49 • ? below 59.49

9. Books • All books are on reserve in the library • Asteroids II • Asteroids III • Comets II • Comet Science • The New Solar System

10. Office Hours • Thursdays 2-4 pm • Drop in anytime if you have problem • IM or email me anytime if you have problem

11. Today • 4-5 pm Asteroids, Comets • 5-6 pm Meteorites • 6-7 pm Students introduce themselves • 10 minute break between classes • We will have lots of definitions today

12. What’s the difference? • Asteroids • Comets • Meteorites

13. What’s the difference? • Asteroids - small, solid objects in the Solar System • Comets - small bodies in the Solar System that (at least occasionally) exhibit a coma (or atmosphere) and/or a tail • Meteorites - small extraterrestrial body that reaches the Earth's surface

14. Why are these things important?

15. Why are these things important? • These things can hit us (and possibly kill us) • They are records of the early solar system • They could be sources of material for mining

16. Moon

17. Probability • Probability of Impact

18. Record of Early Solar System • Meteorites usually have ages of ~4.6 billion years • Asteroids and comets are thought to be the building blocks of the terrestrial planets

19. Resources • In outer space, it may be easier (and less expensive) to extract raw materials from asteroids or comets then to bring them from Earth • Raw materials include water, iron, aluminum, chromium

20. Problem Set #1 • Due next week • It can be found on the syllabus part of website • Problem Set #1

21. Meaning of Asteroid • Asteroid means “star-like” • Called vermin of the sky by astronomers

22. Asteroid Flyby • Movie • Images of 2002 NY40 on August 15-16 • Asteroid has diameter of 700 meters • 524,000 kilometers from Earth (1.3 times the distance of the Earth to the Moon) • Movie over 2 hour time period

23. 951 Gaspra • 17 kilometers long, 10 kilometers wide

24. 433 Eros • Surface of 433 Eros • Landing of NEAR-Shoemaker on Eros

25. When were these objects first discovered? • Comets have been known since the earliest days of mankind • Usually thought to be unlucky • Attacks by heavenly beings on terrestrial people Comet Ikeya-Zhang 153P/Ikeya-Zhang Period of 341 years

26. Halley’s Comet • Edmund Halley figured out that the orbit of the comet of 1682 was nearly the same as those of two comets which had appeared in 1531 and 1607 • Halley concluded that all three comets were in fact the same object returning every 76 years • Halley predicted its return for 1757. • Halley's prediction of the comet's return proved to be correct, although it was not seen until December 25, 1758

27. Titius-Bode Law • The mean distance a (AU) of the planet from the Sun: • a = 0.4 + 0.3 x k • where k=0,1,2,4,8,16,32,64,128 (0 followed by the powers of two) • 1 astronomical unit (AU) is the average distance from the Earth to the Sun

29. So … • Baron Franz Xaver von Zach organized a group of 24 astronomers to search the sky for the "missing planet" • But the first asteroid, 1 Ceres, was not discovered by a member of the group, but rather by accident in 1801 by Giuseppe Piazzi

30. But … • Three other asteroids (2 Pallas, 3 Juno, 4 Vesta) were discovered over the next few years (1802-1807) • After eight more years of fruitless searches, most astronomers assumed that there were no more • However, Karl Ludwig Hencke persisted, and began searching for more asteroids in 1830. • Fifteen years later, he found 5 Astraea, the first new asteroid in 38 years. He also found 6 Hebe less than two years later.

32. Meteorites • Many early cultures recognized (or believed) certain stones as having fallen from the sky • Many early cultures had tools made from iron meteorites • But for most scientists at the time, stones falling from the heavens were considered superstition or heresy

33. More evidence … • In 1492, a meteorite weighing almost 130 kilograms landed near the town of Ensisheim, Alsace, France, then in the hands of Germany

34. Then .. • In 1794, Ernst Friedrich Chladni, considered the father of meteoritics, published a book in which he concluded that stone and iron masses did fall out of the sky • In 1803, thousands of meteorite fragments bombarded L'Aigle in Normandy, France, an event investigated by Jean-Baptiste Biot of the French Academy of Science.

35. Thomas Jefferson • Meteorite landed in Weston, CT in 1807 • It was brought to Yale where it was concluded it was from outer space • Thomas Jefferson, President of the United states, was told about it

36. And responded • "Gentlemen, I would rather believe that two Yankee professors would lie than believe that stones fall from heaven."

37. How are these objects named? • Asteroids • After being observed on two consecutive nights, the object is given a provisional designation • a 4-digit number indicating the year • a space • a letter to show the half-month • another letter to show the order within the half-month • And an optional number to indicate the number of times the second letter has been repeated in that half-month period. • For example, 1977 RG

38. Half Month Discovery • Letter Dates Letter Dates • A Jan. 1-15 B Jan. 16-31 • C Feb. 1-15 D Feb. 16-29 • E Mar. 1-15 F Mar. 16-31 • G Apr. 1-15 H Apr. 16-30 • J May 1-15 K May 16-31 • L June 1-15 M June 16-30 • N July 1-15 O July 16-31 • P Aug. 1-15 Q Aug. 16-31 • R Sept.1-15 S Sept.16-30 • T Oct. 1-15 U Oct. 16-31 • V Nov. 1-15 W Nov. 16-30 • X Dec. 1-15 Y Dec. 16-31 • I is omitted and Z is unused

39. Order within Month • A = 1st B = 2nd C = 3rd D = 4th E = 5th • F = 6th G = 7th H = 8th J = 9th K = 10th • L = 11th M = 12th N = 13th O = 14th P = 15th • Q = 16th R = 17th S = 18th T = 19th U = 20th • V = 21st W = 22nd X = 23rd Y = 24th Z = 25th • I is omitted

40. Asteroids discovered between Sept 16-30 of 1995 • 1995 SA • 1995 SB • ... • 1995 SY • 1995 SZ • 1995 SA1 • … • 1995 SZ1 • 1995 SA2 • ... • 1995 SZ9 • 1995 SA10

41. Asteroid Numbers and Names • When well-observed, asteroid is given a number • 5159 1977 RG • When was it discovered?

42. Asteroid Numbers • When well-observed, asteroid is given a number • 5159 1977 RG • When was it discovered? • 1977 • R Sept.1-15 • G 7th asteroid

43. Asteroid Names • Then the discover gets to name it for period of 10 years or so • 5159 1977 RG • Was named

44. Asteroid Names • Then the discover gets to name it for period of 10 years or so • 5159 1977 RG • Was named • 5159 Burbine

45. Comets • Usually named after discoverer (or person who computed its orbit) • Comet Halley • Number given when discover (or discoverers) have discovered numerous comets • Comet Shoemaker-Levy 9

46. Comets • Comets are now initially designated by the year of their discovery • followed by a letter indicating the half-month of the discovery • and a number indicating the order of discovery • Example, the fourth comet discovered in the second half of February 2006 would be designated 2006 D4.

47. Prefixes • Prefixes are also added to indicate the nature of the comet • P/ - periodic comet (seen two separate times) • C/ - non-periodic comet • X/ - no reliable orbit could be calculated • D/ - a comet which has broken up or been lost • A/ - an object that was mistakenly identified as a comet, but is actually an asteroid

48. Types of Comets • Short period comets – periods < 200 years • Long-Period Comets – periods > 200 years

49. Also • After their second observed perihelion passage, periodic comets are also assigned a number indicating the order of their discovery. • Perihelion is the point where an object is closest to the Sun

50. So • Halley's Comet, the first comet to be identified as periodic, has the systemic designation 1P/1682 Q1 (or 1P/Halley) • Comet Hale-Bopp's designation is C/1995 O1