Books and Multimedia Reviews

Book reviewed in this article: After the First Three Minutes Theory of Thermoluminescence and Related Phenomena by Reuven Chen and Stephen W. S. McKeever. Impakt—Gefahr aus dem All: Das Ende der Zivilisation by Christian Koeberl. Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures by Bevan M. French. The New Solar System, Fourth Edition edited by J. Kelly Beatty, Carolyn Collins Peterson, and Andrew Chaikin.     

Book and Multimedia Reviews

Book reviewed in this article: Encyclopedia of Planetary Sciences edited by J. H. Shirley and R. W. Fairbridge, Chapman and Hall Asteroids: Their Nature and Utilization by Charles T. Kowal Review of Electronic Imaging in Astronomy: Detectors and Instrumentation by I. S. McLean Galileo's Commandment: An Anthology of Great Science Writing edited by Edmund Blair Bolles. W. H. Freeman The Manson Impact Structure, Iowa: Anatomy of an Impact Crater edited by C. Koeberl and R. R. Anderson     

Book and Multimedia Reviews

Book reviewed in this article: Impact Diamonds: Their Features, Origin and Significance by S. A. Vishnevsky, V. P. Afanasiev, K. P. Argunov and N. A. Pal'chick Earth From Above: Using Color-Coded Satellite Images to Examine the Global Environment by Claire L. Parkinson The Elusive Neutrino: A Subatomic Detective Story by Nickolas Solomey     

Book Reviews

Book reviewed in this article: Discovering the Secrets of the Sun by Rudolf Kippenhahn. Protostars and Planets III (eds. E. Levy, J. I. Lunine and M. S. Matthews). Nobel Prize Women in Science: Their Lives, Struggles and Momentous Discoveries by Sharon Bertsch McGrayne. WinMetCat (V. 1.0) Electronic Catalogue of Meteorites and Meteorite Craters by B. Booz, B. Pauli, and R. W. Bühler. Swiss Meteorite Laboratory, P. O. Box 126, CH-8750, Glarus, Switzerland, 1994, sfr 490 (update: sfr 90). MetBase (V. 1.0), Meteorite Data Retrieval Program by J. Koblitz Asteroids, Comets, Meteors 1993: Proceedings of the 160th Symposium of the International Astronomical Union (eds. A. Milani, M. Di Martino and A. Cellino).     

BOOK REVIEWS

Book reviewed in this article: Impact Cratering—A Geologic Process by H. J. Melosh. Origins and Extinctions, edited by Donald E. Osterbrock and Peter H. Raven.     

BOOK REVIEWS

Book reviewed in this article: Meteorites and Their Parent Planets by Harry Y. McSween, Jr. Meteorite Craters by Kathleen Mark. Coon Mountain Controversies. Meteor Impact and the Development of the Impact Theory by William Graves Hoyt. The Tucson Meteorites by Richard R. Willey.     

Book and Multimedia Reviews

Book reviewed in this article: The Three Big Bangs: Comet Crashes, Exploding Stars, and the Creation of the Universe by Philip M. Dauber and Richard A. Muller Stars and Their Spectra: An Introduction to the Spectral Sequence by James B. Kaler Impact!: The Threat of Comets and Asteroids by Gerrit L. Verschuur Cosmic Clouds: Birth, Death, and Recycling in the Galaxy by James B. Kaler     

Archaean asteroid impacts, banded iron formations and MIF-S anomalies: A discussion

The origin of mass-independent fractionation (MIF-S) of sulphur isotopes (δ³³S) recorded in sediments older than 2.45 Ga is widely interpreted in terms of UV-triggered reactions under oxygen-poor ozone-depleted atmosphere conditions (Farquhar, J., Bao, H., Thiemens, M. [2000] Science, 289, 756; Farquhar, J., Peters, M., Johnston, D.T., Strauss, H., Masterson, A., Wiechert, U., Kaufman, A.J. [2007] Nature, 449, 706-709; Farquhar, J., Wing, B.A. [2003] Earth Planet. Sci. Lett., 213, 1-13; Kaufman, A.J., Johnston, D.T., Farquhar, J., Masterson, A.L., Lyons, T.W., Bates, S., Anbar, A.D., Arnold, G.L., Garvin, J., Buick, R. [2007a] Science, 317, 1900-1903; Kaufman, A.J., Farquhar, J., Johnston, D.T., Lyons, T.W., Arnold, G.L., Anbar, A. [2007b] Deep Time Drilling Project of the NASA Astrobiology Drilling Program). Observed mid-Archaean variability of MIF-S signatures raises questions regarding the extent of atmospheric anoxia (Ohmoto, H., Watanabe, Y., Ikemi, H., Poulson, H.R., Taylor, B. [2006] Nature, 406, 908-991; Farquhar et al., 2007). Late Archaean (∼2.7-2.5 Ga) and mid-Archaean (∼3.2 Ga) sequences in the Pilbara Craton (Western Australia) and Kaapvaal Craton (South Africa), in which MIF-S data were measured, contain asteroid impact ejecta units dated as 2.48, 2.56, 2.63, 3.24, 3.26 and 3.47 Ga old (Lowe, D.R., Byerly, G.R., Kyte, T., Shukolyukov, A., Asaro, F., Krull, A. [2003] Astrobiology, 3, 7-48; Simonson, B.M., Hassler, S.W. [1997] Aust. J. Earth Sci., 44, 37-48; Simonson, B.M., Glass, B.P. [2004] Ann. Rev. Earth Planet. Sci., 32, 329-361; Glikson, A.Y. [2004] Astrobiology, 4, 19-50; Glikson, A.Y. [2006] Earth Planet. Sci. Lett., 246, 149-160; Glikson, A.Y. [2008] Earth Planet. Sci. Lett., 267, 558-570). Mass balance calculations based on iridium and ⁵³Cr/⁵²Cr isotopic anomalies (Byerly, G.R., Lowe, D.R. [1994] Geochim. Cosmochim. Acta, 58, 3469-3486; Kyte, F.T., Shukloyukov, A., Lugmair, G.W., Lowe, D.R., Byerly, G.R. [2003] Geology, 31, 283-286) and on impact spherule size distribution (Melosh, H.J., Vickery, A.M. [1991] Nature, 350, 494-497) suggest projectiles several tens of kilometers in diameter (Byerly and Lowe, 1994; Shukloyukov, A., Kyte, F.T., Lugmair, G.W., Lowe, D.R., Byerly, G.R. [2000]. In: Koeberl, C., Gilmour, I. (Eds.), Impacts and the Early Earth, Springer-Verlag, Berlin, pp. 99-116; Kyte, F.T., Shukloyukov, A., Lugmair, G.W., Lowe, D.R., Byerly, G.R. [2003] Geology, 31, 283-286). Due to incomplete preservation these impacts represent a minimum rate of the Archaean impact flux. High UV radiation associated with low ozone levels in the Archaean atmosphere may have been further enhanced by large impacts, accentuating MIF-S anomalies. The appearance of iron-rich sediments above late and mid-Archaean impact ejecta units (Glikson, A.Y. [2006] Earth Planet. Sci. Lett., 246, 149-160; Glikson, A.Y., Vickers, J. [2007] Earth Planet. Sci. Lett., 254, 214-226) may be related either to microbial oxidation of ferrous iron or, alternatively, photochemical oxidation of ferrous to ferric iron. Given post-2.45 Ga diluting of possible MIF-S anomalies by the oxygenating ocean sulfate reservoir (Pavlov, A.A., Kasting, J.F. [2002] Astrobiology, 2, 27-41), similar MIF-S anomalies may have been associated with Proterozoic and Phanerozoic impacts, although to date little evidence exists in this regard (Marouka, T., Koeberl, C., Newton, J., Gilmour, I., Bohor, B.F. [2002] Geological Society of America Special Paper 356, pp. 337-344; Koeberl, C., Thiemens, M. [2008] Multi-sulfur isotopes in cretaceous-tertiary boundary samples from the Western interior-search for photochemical effects 2008. Joint Meeting of the Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM. <http://gsa.confex.com/gsa/2008AM/finalprogram/abstract_148134.htm> (abstract)). Detailed sampling and isotopic analyses across the impact ejecta fallout units are required in order to test possible relationships between Archaean impacts and MIF-S anomalies.     

Books and Multimedia Reviews

Book reviewed in this article: Meteorites: Their Impact on Science and History edited by Brigitte Zanda and Monica Rotaru. The Universe Unveiled: Instruments and Images through History edited by Bruce Stephenson, Marvin Bolt and Anna Felicity Friedman.     

The fraction of solar-type stars having stellar or massive nonstellar companions

The results of the survey for multiplicity by Abt and Levy are used to estimate the fraction of solar-type stars having close companions more massive than 0.01 solar masses. Current knowledge of the multiplicity characteristics of solar-type stars does not require that the fraction be nearly unity.     

近地天体探测现状

本文简要介绍了国内外近地天体探测工作的现状,还介绍了我国正在建造的近地天体探测望远镜的情况。     

Books and Multimedia Reviews

Book reviewed in this article: Encyclopedia of the solar system edited by P. R. Weissman, L-A. McFadden and T. V. Johnson. Worlds Without End: The Exploration of Planets Known and Unknown by John S. Lewis. Impact: Ground Zero (CD-ROM). The Babylonian Theory of the Planets by Noel M. Swerdlow. Einstein's Mirror by Tony Hey and Patrick Walters. Stars by James B. Kaler.     

Book Reviews

Book reviewed in this article: Meteorite Craters and Impact Structures of the Earth by Paul W. Hodge Hunting for Stars by Michel Maurette Radiation and Radioactivity on Earth and Beyond , Second Edition, by Ivan G. Draganic, Zorica D. Draganic, and Jean-Pierre Adloff     

Chandra observations of Comet 9P/Tempel 1 during the Deep Impact campaign

We present results from the Chandra X-ray Observatory's extensive campaign studying Comet 9P/Tempel 1 (T1) in support of NASA's Deep Impact (DI) mission. T1 was observed for ∼295 ks between 30th June and 24th July 2005, and continuously for ∼64 ks on July 4th during the impact event. X-ray emission qualitatively similar to that observed for the collisionally thin Comet 2P/Encke system [Lisse, C.M., Christian, D.J., Dennerl, K., Wolk, S.J., Bodewits, D., Hoekstra, R., Combi, M.R., Mäkinen, T., Dryer, M., Fry, C.D., Weaver, H., 2005b. Astrophys. J. 635 (2005) 1329-1347] was found, with emission morphology centered on the nucleus and emission lines due to C, N, O, and Ne solar wind minor ions. The comet was relatively faint on July 4th, and the total increase in X-ray flux due to the Deep Impact event was small, ∼20% of the immediate pre-impact value, consistent with estimates that the total coma neutral gas release due to the impact was 5×¹⁰⁶ kg (∼10 h of normal emission). No obvious prompt X-ray flash due to the impact was seen. Extension of the emission in the direction of outflow of the ejecta was observed, suggesting the presence of continued outgassing of this material. Variable spectral features due to changing solar wind flux densities and charge states were clearly seen. Two peaks, much stronger than the man-made increase due to Deep Impact, were found in the observed X-rays on June 30th and July 8th, 2005, and are coincident with increases in the solar wind flux arriving at the comet. Modeling of the Chandra data using observed gas production rates and ACE solar wind ion fluxes with a CXE mechanism for the emission is consistent, overall, with the temporal and spectral behavior expected for a slow, hot wind typical of low latitude emission from the solar corona interacting with the comet's neutral coma, with intermittent impulsive events due to solar flares and coronal mass ejections.     

Superhyperbolic expansion,noncollision singularities and symmetry configurations

A large class of symmetry solutions of the Newtonian n-body problem cannot end in a noncollision singularity nor expand faster than any constant multiple of time.Following a suggestion from Christian Marchal, we extended the original theme of this essay to include superhyperbolic motion. The work of D. Saari was supported by NSF Grant ISI 9103180; the work of F. Diacu was supported by NSERC Grant 3-48376     

Spectrophotometry of comet Levy (1990c)

Two spectrophotometric scans of comet Levy (1990c) have been analysed to estimate Haser model column densities and production rates of CN andC ₂ molecules.     

Statistical analysis of plasma turbulence based on satellite magnetic field measurements

The probability density function (PDF) for the magnetic field fluctuations in the Earth’s magnetospheric tail on various time scales is investigated on the basis of Geotail satellite data for 1997, 1999, and 2000. The changes in the shape and parameters of the PDF for the periods before and during the current disruption have been studied. The changes in the height of the PDF maximum P(0) have been investigated as an evolution characteristic on various time scales. Two asymptotic regimes of P(0) characterized by different power laws have been found: the changes in the PDF maximum correspond to a Gaussian process on long time scales and to a Levy distribution on short time scales. The intersection of the two asymptotes corresponds to a time scale of about 1 s. The suggested approach is universal and can be used to analyze the fluctuations in other parameters of a different nature.     

“Comet‐tail” ejecta streaks: A predicted cratering landform unique to Titan

Abstract— A model for an impact ejecta landform peculiar to Saturn's moon Titan is presented. Expansion of the ejecta plume from moderate‐sized craters is constrained by Titan's thick atmosphere. Much of the plume is collimated along the incoming bolide's trajectory, as was observed for plumes from impacts on Jupiter of P/Shoemaker‐Levy‐9, but is retained as a linear, diagonal ejecta cloud, unlike on Venus where the plume “blows out.” On Titan, the blowout is suppressed because the vertically‐extended atmosphere requires a long wake to reach the vacuum of space, and the modest impact velocities mean plume expansion along the wake is slow enough to allow the wake to close off. Beyond the immediate ejecta blanket around the crater, distal ejecta is released into the atmosphere from an oblique line source: this material is winnowed by the zonal wind field to form streaks, with coarse radar‐bright particles transported less far than fine radar‐dark material. Thus, the ejecta form two distinct streaks faintly reminiscent of dual comet tails, a sharply W‐E radar‐dark one, and a less swept and sometimes comma‐shaped radar‐bright one.     

Note on the structure of comet nuclei

The recent developments in cometary studies suggest rather low mean densities and weak structures for the nuclei. They appear to be accumulations of fairly discrete units loosely bound together, as deduced from the observations of Comet Shoemaker–Levy 9 during its encounter with Jupiter. The compressive strengths deduced from comet splitting by Öpik and Sekanina are extremely low. These values are confirmed by theory developed here, assuming that Comet P/Holmes had a companion that collided with it in 1892. There follows a short discussion that suggests that the mean densities of comets should increase with comet dimensions. The place of origin of short-period comets may relate to these properties.     

Planetary atmospheres with ALMA

Thanks to its sensitivity, spatial resolution and instantaneous uv-coverage, ALMA will permit many new studies related to the general topic of the couplings between chemistry and dynamics in planetary atmospheres. It will include: (1) three-dimensional mapping of composition, temperatures and winds in the atmospheres of Mars, Venus and Titan; (2) several aspects of Giant Planet composition and dynamics, such as the origin of oxygen, the evolution of Shoemaker–Levy 9 products in Jupiter’s atmosphere, and the deep atmosphere structure and meteorology; (3) the study of tenuous and distant atmospheres (Io, Enceladus, Pluto, Triton and other Kuiper Belt objects).