DOCSLIB.ORG

O Lunar and Planetary Institute a Provided by the NASA

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
O Lunar and Planetary Institute a Provided by the NASA SEARCHING FOR COMET CORES AMONG APOLLO/AMOR ASTEROIDS. C. A. Wood, SN4INASA Johnson Space Center, Houston, TX 77058 Other than occasional comets, Apollo and hor asteroids (AIA) approach the Earth more closely than any other celestial bodies, and hence are likely contributors to the flux of meteorites. Be- cause dynamic lifetimes of A/A objects are only lo7-lo8 years they must be continually resupplied from a longer-lived source. Orbital dynamical considerations appear to dictate that comets mst supply the majority of A/A1s, but, assuming that meteorites do come from A/A1s, current models of meteorite origins preclude this possibility. This standoff, between theories and models, has con- tinued for nearly 30 years, but sufficient data on A/A objects themselves are now available to con- sider the likelihood of a canetary or asteroidal origin for individual Earth-approaching objects. How to Identify Cometary Cores: Based upon previous discussions, extinct comets in A/A orbits are likely to be distinguishable from objects which escaped from the main asteroid belt by both physical and orbital characteristics (e.g., 1). Shape: Anders (2) argued that small objects such as Icarus (dia -1 km) could not maintain spherical shapes against collisional destruction if they had spent most of the last 4.5 b.y. in the asteroid belt. Collisional fragmentation would be much less likely in the Oort cloud, thus spheric- ity can be interpreted as evidence for a cometary origin of A/A objects. This criteria ignores the splitting of comets, which has only been observed in three shortperiod comets (13). Asteroid sphe- ricity is indicated by a flat light curve; light curve ranges are listed in Tedesco (3). Associated Meteor Streams: Sekanina (4) discovered that the orbits ofil the Apollo asteroid Adonis and the Sigma Capricornids meteor stream are so similar as to imply a likely evolutionary re1ationship." Because meteor streams are known to be derived from comets, Sekanina' s discovery strongly implies a canetary origin for A/Ais with associated meteor streams. Indeed the Apollo object Hephaistos has an orbit similar to that of comet Encke! Sekanina (4) and Drummond (5) have found that ten Apollos and three Amors can be associated with meteor showers; since most Amors do not cross Earth's orbit, detection of Amor-related meteor streams is difficult. Geocentric Velocity: Anders and Arnold (61, noting that Apollo asteroids fell into two groups differing in geocentric velocity, proposed that the low-velocity group was asteroidal and the high- velocity group was canetary. With more than three times as many Apollos now known compared to 1965, the bimodal grouping still exists; based on a minimum in the velocity histogram I propose that a geocentric velocity of 0.8 marks the division. Hi h e i Q: Because most main belt asteroids have low to moderate values of orbital eccentri- city dhkffiic~ination(11, higher values are often considered (e.g., 14 to imply a cometary object. I consider i > 20' or e > 0.5 to suggest a cmetary origin. Similarly, Marsden (7) believes that the single most important factor for distinguishing asteroidal and cmetary orbits is the aphe- 1ian distance (Q). Only 95 asteroids (out of 2500) have Q > 3.9 AU, and no known comet has Q < 4.1 AU; thus Q > 3.9 AU is taken to indicate a possible cometary object. Reduction of Aphelion: As comets sublimate their icy mantles they can experience a nongravita- tional acceleration that reduces their aphel ion, Q. Sekanina (8) has applied a nongravi tational model to A/A objects, finding that six may have had their orbits changed by this process and hence may be cometary nuclei. Constant Eccentricity: Taking into account secular perturbations of orbital elements, Kozai (9) found that of all the asteroids only 11 (all A/A1s) have nearly constant values of e, and hence their aphelian and perihelion distances hardly vary. This is also a property of short period comets and hence Kozai proposes that these 11 are the remains of cometary nuclei. Discussion None of the eight characteristics described above is uniquely diagnostic of a cometary origin (except perhaps associated meteor streams), but each is unexpected for an asteroidal origin. In Table 1 A/A objects are ranked by the percentage of their known characteristics that are indicative of a cometary origin. Note that certain characteristics have not been determined for objects dis- covered since pub1 ication of particular research papers (e.g., 4,9), and that only orbital infona- tion is usually known for most recent discoveries. A remarkable result of this simple study is that 51 of the 64 known A/A objects have one or more cometary characteristics, and 17 (26%) are cmetary in half or more of their properties. Thus, we can conclude that comets probably contribute significantly to the A/A population, and hence, perhaps to our meteorite collections. The spectral types of the most canet-like AIA's(~~O%CC in Table 1)are not definite but include one possible ordinary chondrite, three S types, two C's, a diogenite, three U'S, and eleven unknowns. If all of these objects are derived from canets, then traditional concepts of comets as core-less dirty snowballs are incorrect. Likewise, it would seem impossible for such a diverse group of inferred chemical compositions to have fonned in the outer solar system, reinforcing ideas (10,11,12) that many bodies which formed in the inner solar system became cometary cores. Finally, there appears to be a difference between Apollos and Amors: 35% of Apollos have more than 50% cometary characteristics, whereas Amors are only 17% cometary. This implies that Apollos and Amors may not be a continuum artifically divided by the Earth's orbital radius. If so, derivation of Apollos from the asteroid belt by way of Amor orbits may be very inefficient and perhaps the major- ity of Apollos are extinct comets. References: (1) Kresak, L. (1977) In Comets, Asteroids, Meteors. Univ. Toledo, 313-321. (2) An- ders, t. (197n In "Phys. Studies Minor Planets" NASA SP-ZbI. 429-446. (3) Tedesco. E. F. (19771 In Asteroids, Univ. Arizona, 1098-1078. (4) Sekanina, Z. (1971 1- In "Ph s. Studies in or Planets" NASA -261, 423-428. (5) Drumnond, J. D. (1982) Icarus 49, 143-153. &I Anders, E. and J. R. Arnold (1965) --Science 149, 1494-1496. (7) Marsden, B.-o Tn "Phys. Studies Minor Planets" NASA SP-267, O Lunar and Planetary Institute a Provided by the NASA Astrophysics Data System APOLLOIAMOR COMET CORES Wood, C.A. 413-422;- (8) Sekanina, Z. (1973) Icarus 18, 253-284. (9) Kozai, Y. (1980) Icarus 41, 89-95. (10) Oort, J. H. (1950) Bull. Astron. mem11, 91-110. (8) Wood, C. A. (mui.Am. Astron. Soc. 9, 506. (12) Uood, C. A. and MendelT,A. W. (1982) Lunar Planet. Sci. XIII, 811-878. (13) mpc, F. L. (1982) IAU Repts. XVIII (in press). (14) Gehrels, T. et al. (191(5) Astron. J. 75, 186-1 95. TABLE 1: COMETARY CHARACTERISTICS (CC) OF APOLLOS AND AMORS CC ' s Spectral CC's Spectral Apol 1o Known % CC Type Amor Known % CC Type 1979XB 4 .88 Quetzalcoatl 6 .66 Diogenite 1973NA 6 .83 Ganymede 6 .66 S Hephaistos 5 .80 1963UA 6 .66 1981VA 4 .75 Cuyo 8 .50 Adonis 7 .72 1 981 QB 4 .50 Icarus 8 .69 A1 bert 7 .43 1974MA 5 .60 Betul ia 7 .36 cyu Mi das 5 .60 A1 inda 7 .36 U Sisyphus 5 .60 1978DA 6 .33 cysyu Orthos 5 .60 Ivar 7 .29 S Daedal us 6 .50 1980WF 4 .25 1 97 9VA 4 .50 1982FT 4 .25 Ari staeus 5 .40 Amor 5 .20 Tantal us 5 .40 Pel e 6 .33 PL-6344 5 .40 An za 7 .29 C Apol 1o 8 .37 Anteros 6 .17 S Ra-Shal om 6 .33 Tezcatl ipoca 6 .17 U Antinous 6 .33 Lick 6 .17 1947XCl1979XA 6 .33 Eros 8 .12 OC ,S Hermes 7 .29 1972RB 5 .10 1950DA 7 .29 1982DV 5 0 Hathor 7 .29 1977VA 5 0 U 1982BB 4. .25 1353RA 5 0 S Aten 6 .25 1982XB 4 0 Cerberus 5 .20 1980PA 4 0 1978CA 6 .17 1980AA 4 0 H 1959LM 7 .14 1981 CW 4 0 Toro 8 .I2 1981 QA 4 0 Geographos 8 .12 1977RA 4 0 U PL-6743 5 .10 1954XA 6 0 Bacchus 5 0 1982DB 4 0 1982HR 4 0 Example: For Quetzalcoatl a1 1 of the diagnostic cometary characteris- tics except shape and associated meteor shower have been determined, and 4 (high e, i, Q and reduction in Q) are consistent with a cometary ori- gin; hence % CC = 416 = .66. Note that a score of 0 could occur even for a cometary object so this listing does not distinguish comet AIAs from asteroidal ones, but rather objects with many cometary characteri s- tics from objects with few such properties. O Lunar and Planetary Institute Provided by the NASA Astrophysics Data System .
Load more

Recommended publications
  • 1. Some of the Definitions of the Different Types of Objects in the Solar
    1. Some of the definitions of the different types of objects in has the greatest orbital inclination (orbit at the the solar system overlap. Which one of the greatest angle to that of Earth)? following pairs does not overlap? That is, if an A) Mercury object can be described by one of the labels, it B) Mars cannot be described by the other. C) Jupiter A) dwarf planet and asteroid D) Pluto B) dwarf planet and Kuiper belt object C) satellite and Kuiper belt object D) meteoroid and planet 10. Of the following objects in the solar system, which one has the greatest orbital eccentricity and therefore the most elliptical orbit? 2. Which one of the following is a small solar system body? A) Mercury A) Rhea, a moon of Saturn B) Mars B) Pluto C) Earth C) Ceres (an asteroid) D) Pluto D) Mathilde (an asteroid) 11. What is the largest moon of the dwarf planet Pluto 3. Which of the following objects was discovered in the called? twentieth century? A) Chiron A) Pluto B) Callisto B) Uranus C) Charon C) Neptune D) Triton D) Ceres 12. If you were standing on Pluto, how often would you see 4. Pluto was discovered in the satellite Charon rise above the horizon each A) 1930. day? B) 1846. A) once each 6-hour day as Pluto rotates on its axis C) 1609. B) twice each 6-hour day because Charon is in a retrograde D) 1781. orbit C) once every 2 days because Charon orbits in the same direction Pluto rotates but more slowly 5.
    [Show full text]
  • Jjmonl 1710.Pmd
    alactic Observer John J. McCarthy Observatory G Volume 10, No. 10 October 2017 The Last Waltz Cassini’s final mission and dance of death with Saturn more on page 4 and 20 The John J. McCarthy Observatory Galactic Observer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky Technical Support It is through their efforts that the McCarthy Observatory Bob Lambert has established itself as a significant educational and recreational resource within the western Connecticut Dr. Parker Moreland community. Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Marc Polansky Cecilia Detrich Joe Privitera Dirk Feather Monty Robson Randy Fender Don Ross Louise Gagnon Gene Schilling John Gebauer Katie Shusdock Elaine Green Paul Woodell Tina Hartzell Amy Ziffer In This Issue INTERNATIONAL OBSERVE THE MOON NIGHT ...................... 4 SOLAR ACTIVITY ........................................................... 19 MONTE APENNINES AND APOLLO 15 .................................. 5 COMMONLY USED TERMS ............................................... 19 FAREWELL TO RING WORLD ............................................ 5 FRONT PAGE ...............................................................
    [Show full text]
  • Dealing with the Threat of an Asteroid Striking the Earth
    Dealing with the Threat of an Asteroid Striking the Earth An AIAA Position Paper April 1990 This paper originated in the AIAA Space Systems Technical Committee and was Approved by the AIAA Board of Directors American Institute of Aeronautics and Astronautics 1801 Alexander Bell Drive Reston, VA 20191 703/264-7500 SUMMARY Hundreds, perhaps thousands, of asteroids travel in orbits that intersect the Earth’s orbit. Some have struck the Earth in the past, leaving large craters. Others have come very close, one as recently as March 23, 1989 (Apollo Asteroid 1989FC, estimated to be a fifth to a half mile in diameter). Such an object, if it struck the Earth today, could cause a disaster of unprecedented proportions. Although the probability of such an occurrence is very small, its consequences (i.e., the casualty rate) could be enormous. The risk to Earth’s inhabitants is therefore finite, warranting action to improve and expand our ability to detect Earth- orbit-crossing objects and to analyze and predict their orbits. It would also be useful to explore methods and technologies for deflecting or destroying any such objects that are predicted to impact the Earth and to alter their orbits sufficiently to preclude impact. To begin the process of implementing such action, appropriate experts, both civil and military, should be tasked to formulate specific programs designed to address the issues involved. INTRODUCTION On March 23, 1989, an asteroid bigger than an aircraft carrier, traveling at 46,000 miles per hour, passed through Earth's orbit less than 400,000 miles away. Our planet had been at that point only six hours earlier.
    [Show full text]
  • ~XECKDING PAGE BLANK WT FIL,,Q
    1,. ,-- ,-- ~XECKDING PAGE BLANK WT FIL,,q DYNAMICAL EVIDENCE REGARDING THE RELATIONSHIP BETWEEN ASTEROIDS AND METEORITES GEORGE W. WETHERILL Department of Temcltricrl kgnetism ~amregie~mtittition of Washington Washington, D. C. 20025 Meteorites are fragments of small solar system bodies (comets, asteroids and Apollo objects). Therefore they may be expected to provide valuable information regarding these bodies. How- ever, the identification of particular classes of meteorites with particular small bodies or classes of small bodies is at present uncertain. It is very unlikely that any significant quantity of meteoritic material is obtained from typical ac- tive comets. Relatively we1 1-studied dynamical mechanisms exist for transferring material into the vicinity of the Earth from the inner edge of the asteroid belt on an 210~-~year time scale. It seems likely that most iron meteorites are obtained in this way, and a significant yield of complementary differec- tiated meteoritic silicate material may be expected to accom- pany these differentiated iron meteorites. Insofar as data exist, photometric measurements support an association between Apollo objects and chondri tic meteorites. Because Apol lo ob- jects are in orbits which come close to the Earth, and also must be fragmented as they traverse the asteroid belt near aphel ion, there also must be a component of the meteorite flux derived from Apollo objects. Dynamical arguments favor the hypothesis that most Apollo objects are devolatilized comet resiaues. However, plausible dynamical , petrographic, and cosmogonical reasons are known which argue against the simple conclusion of this syllogism, uiz., that chondri tes are of cometary origin. Suggestions are given for future theoretical , observational, experimental investigations directed toward improving our understanding of this puzzling situation.
    [Show full text]
  • Astrodynamic Fundamentals for Deflecting Hazardous Near-Earth Objects
    IAC-09-C1.3.1 Astrodynamic Fundamentals for Deflecting Hazardous Near-Earth Objects∗ Bong Wie† Asteroid Deflection Research Center Iowa State University, Ames, IA 50011, United States [email protected] Abstract mate change caused by this asteroid impact may have caused the dinosaur extinction. On June 30, 1908, an The John V. Breakwell Memorial Lecture for the As- asteroid or comet estimated at 30 to 50 m in diameter trodynamics Symposium of the 60th International As- exploded in the skies above Tunguska, Siberia. Known tronautical Congress (IAC) presents a tutorial overview as the Tunguska Event, the explosion flattened trees and of the astrodynamical problem of deflecting a near-Earth killed other vegetation over a 500,000-acre area with an object (NEO) that is on a collision course toward Earth. energy level equivalent to about 500 Hiroshima nuclear This lecture focuses on the astrodynamic fundamentals bombs. of such a technically challenging, complex engineering In the early 1990s, scientists around the world initi- problem. Although various deflection technologies have ated studies to prevent NEOs from striking Earth [1]. been proposed during the past two decades, there is no However, it is now 2009, and there is no consensus on consensus on how to reliably deflect them in a timely how to reliably deflect them in a timely manner even manner. Consequently, now is the time to develop prac- though various mitigation approaches have been inves- tically viable technologies that can be used to mitigate tigated during the past two decades [1-8]. Consequently, threats from NEOs while also advancing space explo- now is the time for initiating a concerted R&D effort for ration.
    [Show full text]
  • 8 Asteroid–Meteoroid Complexes
    “9781108426718c08” — 2019/5/13 — 16:33 — page 187 — #1 8 Asteroid–Meteoroid Complexes Toshihiro Kasuga and David Jewitt 8.1 Introduction Jenniskens, 2011)1 and asteroid 3200 Phaethon are probably the best-known examples (Whipple, 1983). In such cases, it Physical disintegration of asteroids and comets leads to the appears unlikely that ice sublimation drives the expulsion of production of orbit-hugging debris streams. In many cases, the solid matter, raising following general question: what produces mechanisms underlying disintegration are uncharacterized, or the meteoroid streams? Suggested alternative triggers include even unknown. Therefore, considerable scientific interest lies in thermal stress, rotational instability and collisions (impacts) tracing the physical and dynamical properties of the asteroid- by secondary bodies (Jewitt, 2012; Jewitt et al., 2015). Any meteoroid complexes backwards in time, in order to learn how of these, if sufficiently violent or prolonged, could lead to the they form. production of a debris trail that would, if it crossed Earth’s orbit, Small solar system bodies offer the opportunity to understand be classified as a meteoroid stream or an “Asteroid-Meteoroid the origin and evolution of the planetary system. They include Complex”, comprising streams and several macroscopic, split the comets and asteroids, as well as the mostly unseen objects fragments (Jones, 1986; Voloshchuk and Kashcheev, 1986; in the much more distant Kuiper belt and Oort cloud reservoirs. Ceplecha et al., 1998). Observationally, asteroids and comets are distinguished princi- The dynamics of stream members and their parent objects pally by their optical morphologies, with asteroids appearing may differ, and dynamical associations are not always obvious.
    [Show full text]
  • Comets, Asteroids, and Meteorites
    Comets, Asteroids, and Meteorites Clues to the Origin of the Solar System Is Pluto a Planet? Introduction • There is evidence that the small amounts of debris that we observe in our Solar System is a remnant of a previous era of intense bombardment that produced frequent impacts on all of the planets – the Late Heavy Bombardment (~4.1 billion years ago) • Moon and Mercury for example, testify to this episode of intense cratering. • Such bombardment was universal and hammered the Earth as well, later to be disguised by erosion and plate tectonics. • The survivors of this original space debris, still exist today, in the form of asteroids, comets, and meteoroids. The 1908 Tunguska Event • First proposed that the Tunguska event was caused by the collision between the Earth and a small comet. • not a reasonable explanation because an icy comet would have exploded too high in the atmosphere to produce the damage seen from the Tunguska event. • consistent with the Earth colliding with an 80-meter diameter, rocky meteoroid traveling at hypersonic speed, about 79,000 km/h. • Some particles consistent in composition with meteoritic dust were found embedded in tree resin at the impact site. • modeled the impact and found it consistent with the impact of a 70-meter diameter stony meteorite that exploded in the atmosphere. 1969 Chihuahua Mexico Event • In 1969 hundreds of people watched while an intense blue-white light crossed the night sky near Chihuahua, Mexico. • punctuated by an explosion that showered the ground with hundreds of rocks, carbonaceous chondrites, all fragments of what is now known as the Allende meteorite.
    [Show full text]
  • 198 5MNRAS.212. .817S Mon. Not. R. Astr. Soc. (1985
    Mon. Not. R. astr. Soc. (1985) 212, 817-836 .817S 5MNRAS.212. Collisions in the Solar System -1. 198 Impacts of the Apollo-Amor-Aten asteroids upon the terrestrial planets Duncan I. Steel and W. J. Baggaley Department of Physics, University of Canterbury, Christchurch, New Zealand Accepted 1984 September 26. Received 1984 September 14; in original form 1984 July 11 Summary. The collision probability between each of the presently-known population of four Aten, 34 Apollo and 38 Amor asteroids and each of the terrestrial planets is determined by a new technique. The resulting mean collision rates, coupled with estimates of the total undiscovered population of each class, is useful in calculating the rate of removal of these bodies by the terrestrial planets, and the cratering rate on each planet by bodies of diameter in excess of 1 km. The influx to the Earth is found to be one impact per 160 000 yr, but this figure is biased by the inclusion of four recently-discovered low-inclination Apollos. Excluding these four the rate would be one per 250 000 yr, in line with previous estimates. The impact rate is highest for the Earth, being around twice that of Venus. The rates for Mercury and Mars using the present sample are about one per 5 Myr and one per 1.5 Myr respectively. 1 Introduction Over the past two decades our knowledge of the asteroids has expanded greatly. Physical studies of these bodies, reviewed by Chapman, Williams & Hartman (1978), Chapman (1983) and in Gehrels (1979), have shown that distinct groups of common genesis exist.
    [Show full text]
  • Planetary Defense Space System Design, MAE 342, Princeton University Robert Stengel
    2/12/20 Planetary Defense Space System Design, MAE 342, Princeton University Robert Stengel § Asteroids and Comets § Spacecraft § Detection, Impact Prediction, and Warning § Options for Minimizing the Hazard § The 2020 UA Project Copyright 2016 by Robert Stengel. All rights reserved. For educational use only. http://www.princeton.edu/~stengel/MAE342.html 1 1 What We Want to Avoid 2 2 1 2/12/20 Asteroids and Comets DO Hit Planets [Comet Schumacher-Levy 9 (1994)] • Trapped in orbit around Jupiter ~1929 • Periapsis within “The Roche Limit” • Fragmented by tidal forces from 1992 encounter with Jupiter 3 3 Asteroid Paths Posing Hazard to Earth 4 4 2 2/12/20 Potentially Hazardous Object/Asteroid (PHO/A) Toutatis Physical Characteristics PHA Characteristics (2013) § Dimensions: 5 x 2 x 2 km § Diameter > 140 m § Mass = 5 x 1013 kg § Passes within 7.6 x 106 § Period = 4 yr km of Earth (0.08 AU) § Aphelion = 4.1 AU § > 1,650 PHAs (2016) § Perihelion = 0.94 AU 5 5 Comets Leave Trails of Rocks and Gravel That Become Meteorites on Encountering Earth’s Atmosphere • Tempel- Temple-Tuttle Tuttle – Period ~ 33 yr – Leonid Meteor Showers each Summer Tempel- • Swift-Tuttle Tuttle Orbit – Period ~ 133 yr – Perseid Meteor Leonid Showers each Summer Meteor Perseid Meteor 6 6 3 2/12/20 Known Asteroid “Impacts”, 2000 - 2013 7 7 Chelyabinsk Meteor, Feb 15, 2013 Chelyabinsk Flight Path, 2013 • No warning, approach from Sun • 500 kT airburst explosion at altitude of 30 km • Velocity ~ 19 km/s (wrt atmosphere), 30 km/s (V∞) • Diameter ~ 20 m • Mass ~ 12,000-13,000
    [Show full text]
  • Lecture 27: Comets & Asteroids Solar System Debris
    Lecture 27: Comets & Asteroids Comets Asteroids Solar System Debris •Interplanetary debris Leftover from the formation of the Solar System Ranges from large asteroids and comets to microscopic dust Rocky material resembles the outer layers of the terrestrial planets Asteroid Icarus 1 Solar System Debris •Interplanetary debris The total mass of the debris is less than that of the Moon These objects are nearly unchanged since the formation of the Solar System Comets •Comets are made of ice and rock, similar to the moons of the outer planets – they are also composed of ancient material Earth Comet Comet’s orbit Sun •Comets fall into two major groups, depending on the period of their orbits (short-period comets and long-period comets) Comet Ikeya-Seki 2 Comets and Asteroids Asteroids •Asteroids are small, rocky bodies that orbit the Sun •Most are smaller than 300 km in diameter •Asteroids have eccentric orbits and spend the majority of their time in the asteroid belt between Mars and Jupiter •The total mass of all asteroids is less than 1/10 the mass of Earth’s Moon. Ida and Dactyl Gaspra 3 Asteroids •The first asteroid discovered was Ceres, detected by Giuseppe Piazzi in 1801 •The orbit of Ceres has semi-major axis of 2.8 AU •Within a few years, Pallas, Juno, and Vesta were discovered •Several hundred thousand asteroids have been discovered •Several thousand new discoveries are made each year Vesta Eros Asteroids •The largest asteroids are: Name Diameter Semi-major axis Eccentricity Ceres 940 km 2.8 AU 0.0789 Pallas 580 km 2.8 AU 0.2299
    [Show full text]
  • Jjmonl 1612.Pmd
    alactic Observer GJohn J. McCarthy Observatory Volume 9, No. 12 December 2016 Water - the elusive elixir of life in the cosmos - Is it even closer than we thought? The John J. McCarthy Observatory Galactic Observer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky It is through their efforts that the McCarthy Observatory Technical Support has established itself as a significant educational and Bob Lambert recreational resource within the western Connecticut Dr. Parker Moreland community. Steve Allison Tom Heydenburg Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Marc Polansky Cecilia Detrich Joe Privitera Dirk Feather Monty Robson Randy Fender Don Ross Randy Finden Gene Schilling John Gebauer Katie Shusdock Elaine Green Paul Woodell Tina Hartzell Amy Ziffer In This Issue "OUT THE WINDOW ON YOUR LEFT"............................... 3 COMMONLY USED TERMS .............................................. 17 TAURUS-LITTROW .......................................................... 3 EARTH-SUN LAGRANGE POINTS & JAMES WEBB TELESCOPE 17 OVER THE TOP ............................................................... 4 REFERENCES ON DISTANCES ........................................
    [Show full text]
  • The Astrology Book the Encyclopedia of Heavenly Influences
    Astrology FM.qxp 12/22/08 12:15 PM Page i y A BOUT THE AUTHOR James R. Lewis has worked as a professional astrologer for more than 25 years. Among astrologers, he is best known for his innovative work on Baby- lonian astrology and on the astrological significance of the planetary moons. Having completed his graduate work in religious studies at the Univer- sity of North Carolina, Chapel Hill, Prof. Lewis has an extensive background in history, psychology, philosophy, and comparative religion, including reli- gious cults. He is an internationally recognized authority on nontraditional religious groups and currently teaches religious studies at the University of Wisconsin at Stevens Point. Prof. Lewis is the author of Visible Ink’s The Death and Afterlife Book, Angels A to Z, and The Dream Encyclopedia. Other titles include Doomsday Prophecies: A Complete Guide to the End of the World, Magical Religion and Mod- ern Witchcraft, and Peculiar Prophets: A Biographical Dictionary of New Religions, and the forthcoming Oxford Handbook of New Religious Movements. His work has received recognition in the form of Choice’s Outstanding Academic Title award and Best Reference Book awards from the American Library Associa- tion and the New York Public Library Association. Astrology FM.qxp 12/22/08 12:15 PM Page ii A LSO FROM V ISIBLE I NK P RESS Angels A to Z The Death and Afterlife Book: The Encyclopedia of Death, Near Death, and Life after Death The Dream Encyclopedia The Fortune-Telling Book: The Encyclopedia of Divination and Soothsaying Real Ghosts, Restless Spirits, and Haunted Places The Religion Book: Places, Prophets, Saints, and Seers The UFO Book: Encyclopedia of the Extraterrestrial Unexplained! Strange Sightings, Incredible Occurrences, and Puzzling Physical Phenomena The Vampire Book: The Encyclopedia of the Undead The Werewolf Book: The Encyclopedia of Shape-Shifting Beings The Witch Book: The Encyclopedia of Witchcraft, Wicca, and Neo-paganism Please visit us at visibleink.com.
    [Show full text]