Invited speakers




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Invited speakers:
Pawel Artymowicz, Stockholm Obs., Sweden

Mailing Address: Stockholm Observatory, SCFAB, SE-106 91 Stockholm, Sweden

E-Mail: pawel@astro.su.se
Alan Boss, CIW, DTM, USA

Mailing Address: 5241 Broad Branch Road, NW, Washington, DC 20015-1305 U.S.A.

E-Mail: boss@dtm.ciw.edu
Adam Burrows, U. Arizona, USA

Mailing Address: Department of Astronomy, University of Arizona, Tucson, AZ 85721 USA

E-Mail: aburrows@as.arizona.edu
Mark Harrison, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: mark.harrison@anu.edu.au
Ray Jayawardhana, U. Michigan, USA

Mailing Address: University of Michigan Astronomy Department, 953 Dennison Building, Ann Arbor, MI 48109-1090 USA

E-Mail: rayjay@umich.edu
Laurie Leshin, Arizona State U., USA

Mailing Address: Arizona State University Department of Geological Sciences, Box 871404, Tempe, AZ 85287-1404 USA

E-Mail: laurie.leshin@asu.edu
Doug Lin, UC Lick Observatory, USA

Mailing Address: UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 USA

E-Mail: lin@ucolick.org
Jonathan Lunine, LPL, AZ, USA

Mailing Address: LPL, 1629 E. University Blvd., Tucson, AZ 85721-0092 USA, Office location: Space Sciences 522

E-Mail: jlunine@lpl.arizona.edu
Kevin McKeegan, UCLA, USA

Mailing Address: Dept. of Earth & Space Sciences, UCLA, 595 Young

Drive, Los Angeles, CA. 90095-1567 USA

E-mail: mckeegan@ess.ucla.edu


Frank H. Shu, National Tsing Hua U., Taiwan

Mailing Address: National Tsing Hua University 101, Sec. 2, Kuang Fu Road, Hsichu 30013, Taiwan, R.O.C.

E-Mail: shu@mx.nthu.edu.tw
Chris Tinney, Anglo-Australian Obs., Australia

Mailing Address: PO Box 296, Epping 1710 Australia

E-mail: cgt@aaoepp.aao.gov.au

Contributed talks:
Francis Albarede, Ecole Normale Sup. de Lyon, France

Mailing Address: Ecole Normale Supérieure de Lyon 46, Allee d'Italie 69364 Lyon Cedex 7, France

E-Mail: albarede@ens-lyon.fr
Yuri Amelin, Geological Survey of Canada

Mailing Address: Geological Survey of Canada, 601 Booth St., Ottawa, ON, Canada, K1A 0E8

E-Mail: yamelin@NRCan.gc.ca
Jeremy Bailey, AAO, Australia

Mailing Address: Anglo-Australian Observatory, PO Box 296, Epping,

NSW 1710

E-mail: jab@aaoepp.aao.gov.au


Victoria C. Bennett, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: Vickie.Bennett@anu.edu.au
Mike Bessell, RSAA, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: bessell@mso.anu.edu.au
Brad Carter, U. of Southern Queensland, Australia

Mailing Address: Centre for Astronomy, Solar Radiation and Climate, Department of Biological and Physical Sciences, Faculty of Sciences, University of Southern Queensland, Toowoomba Queensland 4350, Australia

E-Mail: carterb@usq.edu.au
Geoff Davies, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: Geoff.Davies@anu.edu.au
Ulyana Dyudina, RSAA, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-mail: ulyana@gps.caltech.edu
Justin Freeman, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: justin.freeman@anu.edu.au
Andrew Glikson,RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: andrew.glikson@anu.edu.au
Karl E. Haisch Jr., U. Michigan, USA

Mailing address: Dept. of Astronomy, Univ. of Michigan, 830 Dennison Bldg., Ann Arbor, Michigan 48109-1090 USA

E-mail: khaisch@umich.edu
Masahiko Honda, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: Masahiko.Honda@anu.edu.au
Trevor Ireland, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: trevor.ireland@anu.edu.au
Ing-Guey Jiang, Astronomy, National Central U., Taiwan

Mailing Address: Institute of Astronomy, National Central University, No. 300, Jungda Rd, Jungli City, Taoyuan, Taiwan 320, R.O.C.

E-Mail: jiang@astro.ncu.edu.tw
Warrick Lawson , UNSW@ADFA, Australia

Mailing address: School of PEMS/Physics, UNSW@ADFA, Canberra ACT 2600

E-mail: wal@ph.adfa.edu.au
Kurt Liffman, CSIRO and Monash U., Australia

Mailing Address: Energy & Thermofluids Engineering, CSIRO/MIT P.O. Box 56, Graham Rd, Highett VIC 3190 AUSTRALIA

E-mail: Kurt.Liffman@csiro.au
Charley Lineweaver, UNSW, Australia

Mailing Address: School of Physics, University of New South Wales, Sydney, NSW 2052

Email: charley@bat.phys.unsw.edu.au
Sarah Maddison, Swinburne U., Australia

Mailing Address: Centre for Astrophysics and Supercomputing, School of BSEE, Swinburne University of Technology, PO Box 218, Hawthorn, 3122 Victoria, Australia

E-Mail: smaddison@swin.edu.au
Rosemary Mardling, CSPA, Monash U., Australia

Mailing Address: School of Mathematical Sciences, Monash University, 3800

E-mail: rosemary.mardling@sci.monash.edu.au
Franklin Mills, RSPhysSE, ANU, Australia

The Research School of Physical Sciences and Engineering, Building 60, ANU Campus, Canberra ACT 0200

E-Mail: frank.mills@anu.edu.au
Louis Moresi, Monash U., Australia

Mailing address: School of Mathematical Sciences Building 28, Monash University, Clayton 3800, Victoria, Australia

E-mail: louis.moresi@sci.monash.edu
James Murray, Swinburne U., Australia

Mailing Address: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn Victoria 3122, Australia

E-Mail: jmurray@astro.swin.edu.au
Marc Norman, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: marc.norman@anu.edu.au
Allen Nutman, RSES, ANU, Australia

Mailing address: Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia

E-mail: allen.nutman@anu.edu.au
Andrew Prentice, Monash U., Australia

Mailing Address: Room 329, Building 28, School of Mathematical Sciences, Monash University Vic 3800, Australia

E-Mail: andrew.prentice@sci.monash.edu.au
Penny D. Sackett, RSAA, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: director@mso.anu.edu.au
Thomas Sharp, Arizona State U., USA

Mailing Address: Arizona State University Department of Geological Sciences, Box 871404, Tempe, AZ 85287-1404 USA

E-Mail: tsharp@asu.edu

Therese Schneck, Consulting Civil Engineer, France

Mailing Address: 11/13 Rue Lobineau 75006 Paris

E-Mail: SCHNECKT@netscape.net


Robert G. Smith, UNSW@ADFA, Australia

Mailing Address: School of Physical, Environmental & Mathematical Sciences, University of New South Wales at The Australian Defence Force Academy, Canberra, ACT 2600

E-mail: r.smith@adfa.edu.au
Dave Stegman. Mathematical Sci., Monash U., Australia

Mailing Address: School of Mathematical Sciences, Monash University Building 28 Victoria 3800 Australia

E-Mail: dave.stegman@sci.monash.edu.au
Ross Taylor, Geology, ANU, Australia

Mailing Address: Geology Department, The Australian National University, Canberra 0200 ACT Australia

E-Mail: ross.taylor@anu.edu.au
Mark Wardle, Macquarie U, Australia

Mailing Address: Department of Physics, Macquarie University, Sydney NSW 2109

E-mail: wardle@physics.mq.edu.au
David Wark, Monash U., Australia

Mailing Address: School of Geosciences, Building 28 Monash University Victoria 3800, Australia

E-Mail: warkd@rpi.edu
Peter Wood, RSAA, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: wood@mso.anu.edu.au
Chris Wright, ADFA@UNSW, Australia

Mailing Address: School of Physical, Environmental & Mathematical Sciences, University of New South Wales at The Australian Defence Force Academy, Canberra, ACT 2600

E-Mail: wright@ph.adfa.edu.au
Li-Chin Yeh, National Hsinchu Teachers College, Taiwan

Mailing Address: Department of Mathematics, National Hsinchu Teachers College, Hsin-Chu, Taiwan

E-mail: lcyeh@BSD.NHCTC.edu.tw
Williaml Zealey, U. of Wollongong, Australia

Mailing Address: Faculty of Engineering, University of Wollongong, Wollongong, NSW2500

E-mail: b.zealey@uow.edu.au

Students:

Daniel Bayliss, MSO, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-mail: bayliss@mso.anu.edu.au


Adrian Brown, Macquarie U, Australia

Mailing address: Dept of Earth and Planetary Sciences, Macquarie Uni, NSW 2109

E-mail: abrown@els.mq.edu.au
Andres Carmona, ESO Garching., Heidelberg U., Germany

Mailing Address: European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Muenchen, Germany

E-mail: acarmona@eso.org
Marie Gibbon, Monash U., Australia

Mailing Address: 42 Park Street, Seaford Vic 3198

E-mail: marie.gibbon@maths.monash.edu.au
Antti Kallio, RSES, ANU, Australia

Mailing Address: RSES, Building 61, The Australian National University, Canberra ACT 0200 Australia

E-Mail: antti.kallio@anu.edu.au
Gareth Kennedy, Monash U., Australia

Mailing Address: 2/33 Golf Links Ave, Oakleigh, Vic, 3166

E-mail: gareth.kennedy@maths.monash.edu.au
A-Ran Lyo, UNSW@ADFA, Australia

Mailing address: School of PEMS/Physics, UNSW@ADFA, Canberra ACT 2600

E-Mail: arl@ph.adfa.edu.au

Marco M. Maldoni, UNSW@ADFA, Australia

Mailing address: School of PEMS/Physics, UNSW@ADFA, Canberra ACT 2600

E-Mail: m.maldoni@adfa.edu.au.


Charles Morgan, Monash U., Australia

Mailing Address: School of Mathematical Sciences, Monash University, Clayton, Vic. 3800

E-mail: charles.morgan@maths.monash.edu.au
Craig O'Neill, U. Sydney, Australia

Mailing Address: The School of Geosciences, Department of Geology and Geophysics Edgeworth David Building F05, The University of Sydney, NSW 2006


Dr. John Patten, Unaffiliated Student, Australia
Kala Perkins, SRES, ANU, Australia

Postal Address: School of Resources, Environment and Society, Australian National University, Canberra 0200 Australia

E-Mail: kala.perkins@anu.edu.au
Tamara Rogers, U. Santa Cruz, USA

Mailing Address: 5350 S. Morning Sky Ln, Tucson, AZ. 85747

E-mail: trogers@es.ucsc.edu
Raquel Salmeron, U. Sydney, Australia

Mailing Address: School of Physics A28, University of Sydney, NSW 2006, Australia

E-Mail: salmeron@physics.usyd.edu.au
Patrick Scott, MSO, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: pat@mso.anu.edu.au
Christine Thurl, MSO, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: cthurl@mso.anu.edu.au
Miguel de Val Borro, Stockholm U., Sweden

Mailing Address: Stockholm University, AlbaNova Center, Department of Astronomy, 10691 Stockholm

E-mail: miguel@astro.su.se
David Weldrake, RSAA, ANU, Australia

Mailing Address: Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611, Australia

E-Mail: dtfw@mso.anu.edu.au


Abstracts


Yuri Amelin (1),  Alexander Krot (2) and Eric Twelker (3)

1) Geological Survey of Canada

2) Hawaiian Institute of Geophysics and Planetology, SOEST, University of Hawaii at Manoa,

3) Juneau




Duration of the chondrule formation interval: a Pb isotope study
Chondrules are among the earliest solid objects that formed in the solar system.
We have  determined the ages of chondrules from several carbonaceous chondrites using the Pb-Pb isochron method. High precision Pb isotope dates are obtained for three silicate clasts (large chondrules) from the CBa (Bencubbin-like) chondrite Gujba. Additional analyses of chondrules from the CV3 chondrite Allende allowed to improve precision of the age. The summary of precise Pb-Pb ages of chondrules from primitive chondrites is shown below:
Meteorite Pb-Pb isochron age, Ma Comment

Allende (CV3) 4566.7±1.0 this study

Acfer 059 (CR2) 4564.7±0.7 Amelin et al. (2002)

Gujba (CBa) 4562.7±0.5 this study


From these data, we deduce that the period of chondrule formation started simultaneously with, or shortly after the CAI formation [4567.2±0.6 Ma (Amelin et al., 2002)], and continued for at least 4.0±1.5 m.y. If the dates of the chondrules reflect their timing of formation, then there were probably a variety of processes occurring over at least 4-5 m.y. that we now combine under the umbrella name of "chondrule formation".  More high-precision Pb-Pb and extinct nuclide dating, as well as geochemical and petrologic studies of chondrules from primitive meteorites, will be  required to understand individual processes of chondrule formation.



Pawel Artymowicz

Stockholm Univ


Migration of bodies in disks: Timescales and unsolved problems
Solid bodies with size ranging from dust to planets are present in  protoplanetary disks, with which they couple via processes involving gas drag, radiation pressure, and gravitational torques of several types (due to Lindblad and corotational resonances).  As a result, several size-dependent migration modes exist, operating on timescales shorter than the lifetime of the disks. Theory of migration studies the role of mobility in accumulation of solids, origin of the orbital distance distribution of extrasolar planets, and the ring-like appearence of some circumstellar dust disks.  This talk presents an overview of the underlying physics, timescales, and the outcomes of migration in the scenarios of planetary system formation.  We discuss in some detail a newly discovered, fast migration mode of protoplanets (timescale ~1000 yr), dependent on corotational torques (tentatively named type III).

Jeremy Bailey

AAO
Evolution of Terrestrial Planet Atmospheres

Time when the process started in the solar system:  -4.5 byr

Time when it ended:   still continuing


The planets Venus, Earth and Mars have developed very different atmospheres over 4.5 billion years of evolution, although we suspect that their early atmospheres may have been quite similar. Mars has a very thin (7 mbar) and dry atmosphere of mostly CO2. The Earth's 1 bar atmosphere is predominantly nitrogen and oxygen with very low CO2 content, and Venus has a 90 bar atmosphere of mostly CO2 in which a runaway greenhouse effect has heated the planets surface to 720K. I will review some of the processes which have operated on the three planets to control the evolution of their atmospheres, and discuss issues including the "early faint Sun" problem, "snowball Earth" events and the rise of oxygen in the Earth's atmosphere.

Jeremy Bailey (1,2),  Sarah Chamberlain (2),  Malcolm Walter (2) and David Crisp (3)

(1) AAO


(2) Australian Centre for Astrobiology, Macquarie University

(3) Jet Propulsion Laboratory, Caltech


Poster: IR Observations of Mars during the August 2003 opposition
We present some preliminary results of observations obtained during the very favourable opposition of Mars in August 2003 using the UIST instrument on the United Kingdom Infrared Telescope (UKIRT) at Mauna Kea, Hawaii. We obtained narrow band images which we believe are probably the sharpest ever obtained with a ground-based telescope, as well as spectral scans of the disk at a range of near-IR wavelengths and resolving powers. The observations include absorption features due to atmospheric gases, CO2 ice at the south pole, and water ice clouds in the north. We can use the CO2 band strength to image the distribution of surface atmospheric pressure and hence topography.
The data may be used to search for absorption features due to hydrated clay minerals, carbonates and sulphates which might provide evidence for the past presence of surface water.

Jeremy Bailey (1),  Phil Lucas (2), Jim Hough (2) and Motohide Tamura (3)

(1) AAO & Australian Centre for Astrobiology, Macquarie U.

(2) University of Hertfordshire

(3) National Astronomical Observatory, Japan


Poster: Direct Detection of Extrasolar Planets by Polarimetry
Despite the detection of more than 100 extrasolar planets by the radial velocity method, no extrasolar planet has yet been seen directly by its emitted or reflected light. Detections by spectroscopic techniques have so far been unsuccessful while photometric detection requires accuracies which are beyond current ground-based photometry.

However, we believe that planets orbiting close to their stars (Hot Jupiters) might be detected by means of the polarization of the light scattered from their atmospheres. While the resulting polarization of the combined light of the planet and star is small, polarization measurements can in principle be made with very high sensitivity since polarimetry is a differential measurement and is not limited by the stability of the Earth's atmosphere as photometry is.


We have designed and built a stellar polarimeter which should be capable of achieving the required sensitivity. The instrument is now being tested, and on a 4m or larger telescope should be capable of detecting the polarization signature of bright hot Jupiter systems such as Tau Boo, Upsilon And or 51 Peg.


Daniel Bayliss, Ulyana Dyudina and Penny Sackett

RSAA, ANU, Australia


Modeling of Reflected Light from Extra Solar Planets with Eccentric Orbits
An extra solar planet will shine by reflecting light from its parent star.  As the planet orbits the star the amount of light reflected will vary as the phase of the planet changes with respect to the observer, resulting in a light curve with a periodicity equal to the orbital period of the planet.  We model the reflected light from extra solar planets at different phases based the reflective properties of Jupiter and Saturn obtained by the Pioneer space probes.  Since a large proportion of the known extra solar planets display highly elliptical orbits, our models include changes in angular velocity and orbital distance resulting from such elliptical orbits.  Current Earth based photometry is limited to a precision of about 100ppm of the parent's stars luminosity due to atmospheric extinction.  However, new space photometers such as MOST and Kepler, are expected to have precisions down to less than 10ppm. At these new sensitivities the light curves from many known extra solar planets should be detectable.  These light curves should give us information not only on the size and orbital properties of the planet, but also on atmospheric particle size, cloud cover, and the presence of rings.  We discuss the likelihood of these properties being extracted from the light curves with the data from space and earth based instruments in the next 5-10 years.

Alan Boss

Carnegie Institution


The Formation of Giant Planets

[All times relative to formation of the protosun and solar nebula]


Time core accretion started: 0 Myr Error bar: 0 Myr

Time core accretion finished: 5 Myr Error bar: 2 Myr

Time disk instability started: 0 Myr Error bar: 0.1 Myr

Time disk instability finished: 0.1 Myr Error bar: 0.1 Myr


Two very different mechanisms have been proposed for the formation of the gas and ice giant planets. The conventional explanation for the formation of gas giant planets, core accretion, presumes that a gaseous envelope collapses upon a roughly 10 Earth-mass, solid core that was formed by the collisional accumulation of planetary embryos orbiting in the solar nebula. The more radical explanation, disk instability, hypothesizes that the gaseous portion of the nebula underwent a gravitational instability, leading to the formation of self-gravitating clumps, within which dust grains coagulated and settled to form cores. Core accretion appears to require several million years or more to form a gas giant planet, implying that only long-lived disks would form gas giants. Disk instability, on the other hand, is so rapid (forming clumps in thousands of years), that gas giants could form in even the shortest-lived disks. Core accretion has severe difficulty in explaining the formation of the ice giant planets, unless two extra protoplanets are formed in the gas giant planet region and thereafter migrate outward.
Recently, an alternative mechanism for ice giant planet formation has been  proposed, based on observations of protoplanetary disks in the Orion: disk instability leading to the formation of four gas giant protoplanets with cores, followed by photoevaporation of the disk and gaseous envelopes of the protoplanets outside about 10 AU by a nearby OB star, producing ice giants. In this scenario, Jupiter survives unscathed, while Saturn is a transitional planet.

Adrian Brown

Dept of Earth and Planetary Sciences, Macquarie University


Evidence for the earliest Hydrothermal System on Earth in the East Pilbara Granite-Greenstone Terrane
Time  when the process you  describe started in the solar system: 3.45 Gy

The error bar on the start time: 100 My

Time when this process ended: 3.46

The error bar on the end time: 100 My


The East Pilbara Granite Greenstone Terrane is a well preserved Archaean succession of domical granite batholiths surrounded by thick greenstone synclinoria. The North Pole Dome region in postulated to be a granite dome predominantly covered by greenstones of the Warrawoona Group. Following intrusion of the granite and eruption of the felsic Panorama Formation around 3.45 Gya, it is hypothesized that a hydrothermal event took place, utilising the felsic magma conduits to propel water to the palaeosurface, thereby creating an epithermal hydrothermal deposit at Miragla Creek. The alteration caused by this event is in the process of being mapped using airborne hyperspectral sensing as part of a three year PhD project. It provides an opportunity to examine one of the earliest hydrothermal events in the history of the Earth.

The 600 sq. km hyperspectral dataset was captured in October 2002 and covers the wavelengths from 400 to 2400 nm at 5m resolution. Mapped litholgies so far include sericite, chlorite and pyrophyllite alteration zones, along with a serpentine-rich komatiite flow at the base of the Apex Basalt. These will be discussed and implications of the event, including its possible links with putative stromatolite structures within the 3.42 Gyr Strelley Pool Chert, which overlies the Panorama Formation.


Adam Burrows

U. Arizona


Direct Detection of Extrasolar Giant Planets
Over the past eight years we have seen the number of known extrasolar giant planets (EGPs) grow from 1 in 1995 to more than 110 today.  However, these epochal discoveries outside our solar system have been made using indirect techniques.  In order to truly characterize their physical and chemical nature, more direct detection of the light of the planets themselves is necessary.  To this end, NASA and ESA have embarked upon an ambitious plan of direct planet measurement that includes projects with the KIA, LBTI, VLTI, SIM, GAIA, Kepler, COROT, MOST, MONS, WISE, JWST, and the Spitzer Space Telescope.
I will review theoretical calculations of the atmospheres, spectra, and evolution of irradiated EGPs as a function of mass, age, orbital separation, eccentricity, primary star, and composition.  Moreover, I will describe EGP albedos and orbital phase functions, as well as transit physics. The predictions I summarize are predominantly to inform the numerous direct discovery campaigns being planned for the next decade.  
 


Andres Carmona

European Southern Observatory. Garching. & Heidelberg University. Heidelberg, Germany


Observational studies of gas in circumstellar disks around YSO

Time when the process you describe started in the solar system: 0

The error bar on the start time: -

Time when this process ended: 5 Myr

The error bar on the end time: 1 Myr
Circumstellar disks around young stellar objects (YSO), where the process of planet formation is thought to take place, consist nearly 99% of gas. However, until the present, a great part of the observational effort in understanding YSO's disks has been focused on the study of the dust. It is well known that dust causes
the bulk of infrared continuum radiation, as well as strong infrared spectroscopic features. Interesting insights on the physics of the disks has been consequently obtained even at low spectroscopic resolution. Unfortunately, dust does not provide kinematic information that allow the detailed study of the dynamics of the disk. Indeed dust observations don't permit a direct measure of the mass distribution as a function of the distance to the star. On the theoretical arena, recent studies of planet formation focused principally on the study of the dynamics of the gas in the circumstellar disk. It appears that observational work aimed to study the gas is
necessary and fundamental for constructing a more accurate picture of the planet formation process. Specifically, gas studies are vital to constrain and observationally test theoretical scenarios proposed about giant planet formation and migration in particular.Gas has weaker features, so observationally harder to study. However with gas it is possible to obtain kinematic information. Only advanced technology allowing extremely high spectral resolution would permit to resolve the weak spectral features associated with circumstellar gas. Only 8m class telescopes are able to provide the high angular resolution required to spatially resolve the disks around a close stellar objects.The ESO-VLT capabilities combined with a new generation of high
resolution infrared spectrometers (VISIR and CRIRES) will allow astronomers for the first time to study the gas and the dynamics circumstellar disks. However, even with the best instrumentation available, to be able to resolve the disks and perform detailed gas studies, young, close, ^Óbig^Ô and bright, stellar objects are required. Young intermediate mass stars Herbig Ae/Be appear to be the more suitable targets for effectuating this new and challenging research.

Brad Carter

USQ www.usq.edu.au/users/carterb


The Anglo-Australian Planet Search

Time when the process you describe started in the solar system: 3Gyr (2 Gyr ago)

The error bar on the start time: 1 Gyr

Time when this process ended: 5 Gyr

The error bar on the end time: 1 Gyr

(The above figures represent the fact that the exoplanets to be


discussed are mature objects thought to be several billion years old to
roughly solar age or perhaps older.)

The Anglo-Australian Planet Search (AAPS) is currently surveying about 250 generally solar-type stars in the southern sky, to detect orbiting planets using stellar reflex motion. Precision Doppler measurements of stellar radial velocity are made with the Anglo-Australian Telescope (AAT) equipped with an echelle spectrograph and an iodine absorption cell. The spectrograph point spread function and wavelength calibration are derived from the iodine line spectra, resulting in a long term precision of 3 metres per second. Because the magnetic activity of young stars produces a jitter that affects precision radial velocity measurements, the target stars selected are older than 3 Gyr and their planets are "mature" objects. The AAPS has revealed more than a dozen planet candidates with minimum mass ranging from 0.2 to 10 times the mass of Jupiter, and an additional four planet candidates have been confirmed. For the most part the exoplanets detected are in eccentric or close orbits that are in marked contrast to our solar system. Nevertheless, a recent result is the detection of a planet orbiting the star HD70642 that suggests a planetary system architecture similar to our own.


      
Geoff Davies

Research School of Earth Sciences, Australian National University


Stratifying the Earth

Time when the process started: Magma ocean: during Mars-sized impact, late stage of accretion, say 30 Ma after meteorite formation (4.56 Ga).

The error bar on the start time: 15 Ma

Time when this process ended: 5000 years later

The error bar on the end time: 3000years

OR

Time when the process started: Removal of excess accretional heat from Earth's interior:  late stage of accretion, 30 Ma after meteorite formation (4.56 Ga).



The error bar on the start time: 15 Ma

Time when this process ended: 400 Ma later (4.2 Ga)

The error bar on the end time:  200 Ma
The Earth's iron core probably began to segregate when the Earth was about half grown, and would then have kept pace with the growth of the Earth, assuming Earth formation lasted a few to a few tens of millions of years.
A magma ocean would freeze out in thousands of years, even if it were hundreds of kilometers deep, unless there was a dense, opaque early atmosphere to keep the surface hot.  Thus a global magma ocean is only likely to have occurred after giant impacts, and then only briefly.  Transient magma seas or lakes would have formed after lesser large impacts.
Basaltic crust would have begun to form as soon as melting began, during the later stages of accretion, and this would continue to the present day through mantle convection.  Relatively thick basaltic crust (10-50 km) would have been forming as the Earth approached its final size, and would have persisted through the early phase of internal heat dissipation.  The mantle strongly self-limits thermally at higher temperatures.

The excess internal heat left from accretion would be removed by mantle convection over a few hundred million years.  Thereafter the internal temperature would have slowly declined as the main radioactive heat sources (U, Th, K) decayed by a factor of about 4.


Much of the early basaltic crust may have been subducted and settled to the bottom of the mantle because under pressure it becomes denser than the mantle.  It could have formed a layer 100-1000 km thick, which could explain early geochemical depletion of "incompatible" elements in the upper mantle.
Continental crust, closer to granitic composition, apparently accumulated only slowly during the first billion years, more rapidly for the next billion years, and then more slowly again.

U. Dyudina(1), P.Sackett(1), D. Bayliss(1), L Dones(2), H. Throop (2), A. Del Genio(3), C. Porco(4), S. Seager(5)

(1) Mount Stromlo Obs., Australian National University

(2) Southwest Research Institute, Boulder, USA

(3) NASA Goddard Institute for Space Studies, NY, USA

(4) Space Science Institute, Boulder, USA

(5) DTM, Carnegie Institute at Washington, USA


Disk-averaged phase light curves of extrasolar Jupiter and Saturn.
Time when the process you describe started in the solar system: 106 y

The error bar on the start time: ranges from 105 to 106 y

Time when this process ended: continuing
We predict how the remote observer would see the brightness of the giant planets vary as they orbit the star. The prediction is based on our empirical model of Jupiter, Saturn, and Saturn's rings reflectivity. The planets' and rings' surface reflectivity and the phase angle dependence of the reflectivity is derived from Pioneer and Voyagers spacecraft observations. We model the planets and the rings at different planets' obliquities and different viewing geometries. We derive the disk-averaged brightness of the planet and rings depending on the  orbital inclination and eccentricity.
Back-scattering effect of the real atmosphere makes the planet appear several times brighter than Lambertian sphere at full phase. The rings make the planet appear several times brighter at some geometries. A planet with rings produces complicated non-symmetric light curve as it orbits the star and changes phase. The brightest point on the curve may be different from the full phase geometry. This asymmetry together with a specific shape of the light curve may allow detection of rings in the precise photometry observations.
We will discuss detectability of extrasolar planets and the rings around the planets using their phase light curves.

J. Freeman (1), L. Moresi (2) and D. May (3)

(1) ANU


(2) Monash University

(3) VPAC, Monash University




Stagnant Lid Convection with a Water Ice Rheology
Numerical investigations of thermal convection with strongly temperature dependent Newtonian viscosity (diffusion creep) and extremely large viscosity contrasts have demonstrated the existence of three convective regimes. These are the small viscosity contrast regime, transitional regime and the stagnant lid regime. The strong temperature dependence of water ice suggests that convection operating within the mantle of an icy satellite should be within the stagnant lid regime. We study the evolution into the stagnant lid regime with a water ice rheology by solving the equations of thermal convection for a creeping fluid with the Boussinesq approximation and infinite Prandtl number. The viscosity is non-Newtonian (dislocation creep). We fix the Rayleigh number at the base ($Ra_1$) to be $1\times 10^4$ and systematically increase the viscosity contrast (as determined by $\Delta T$) over the region from $\Delta \eta = 1$ to $10^{14}$. The transition to the stagnant lid regime occurs at a viscosity contrast greater than $10^4$ for Newtonian viscosity convection, whilst non-Newtonian viscosity convection accommodates the stagnant lid regime at larger viscosity contrasts.
For a stress exponent, $n$, equal to 3, the stagnant lid regime is achieved at a viscosity contrast greater than $108$. Dislocation creep of water ice is characterized by a larger stress dependence ($n=4$) than silicates ($n=3$), and with this water ice rheology, the stagnant lid regime is attained at a viscosity contrast greater than $1010$.
Andrew Glikson

RSES, ANU


Early terrestrial maria-like impact basins: mineralogy and chemistry of early
Precambrian asteroid impact ejecta, Pilbara and Transvaal, may imply existence of large oceanic impact basins on the early Precambrian Earth.
3.8 to 2.4 billion years interval

1. Episodic Precambrian asteroid impacts, with which my abstract is


concerned, follow the major impact episode at 3.95-3.85 billion years,
generally referred to as the "Late Heavy Bombardment" (LHB).

2. The error bar on the onset of the post-LHB era at about 3.85 billion


years ago would be about +/-20 or 30 million years.

3. Impact by large asteroid clusters, with which the paper is concerned,


continue throughout geological history, the last being about 35 billion
years ago (late Eocene).

Asteroid impact fallout units, consisting of microkrystite (impact condensate) spherules and microtektites, increasingly allow the deciphering of the early impact history of Earth. In a paper of key importance, B.M. Simonson, D. Davies, M. Wallace, S. Reeves, and S.W. Hassler, (1998, Iridium anomaly but no shocked quartz from Late Archie microkrystite layer: oceanic impact ejecta?, Geology, 26:195-198) point out the likely oceanic (mafic-ultramafic) crustal source of early Proterozoic impact ejecta in the Pilbara Craton, Western Australia. Studies of mainly chloritic microkrystite spherules from the Barberton greenstone belt, Transvaal, are consistent with a mafic derivation of impact condensates (Lowe et al., 1989; Byerly and Lowe. 1994; Shukloyukov et al., 2000; Kyte et al., 2003; Lowe et al., 2003). Recent field and geochemical studies of Archaean to early Proterozoic impact units in the Pilbara Craton (Glikson and Vickers, 2003) lend support to Simonson et al.'s (1998) suggestion, on the following basis:


[1] Siderophile element (Ni, Co), ferroan elements (Cr, V) and Platinum Group Element (PGE) patterns of least-altered microkrystite (impact-condensate) spherules and microtektites from Archaean and early Proterozoic impact fallout in the Pilbara Craton (northwestern Australia) and the Kaapvaal Craton (Transvaal) (Table 1) indicate a mafic/ultramafic composition of impact target crust.

[2] No shocked quartz grains are observed in the impact fallout units.


Estimates of asteroid and crater sizes based on (a) Mass balance calculations of asteroid masses based on the flux of Iridium and Platinum as measured from impact fallout units, and (b) spherule size-frequency distribution using the method of Melosh and Vickery (1991), provide evidence for asteroids several tens of kilometer in diameter (Byerly and Lowe,1994; Shukloyukov et al., 2000; Kyte et al.; Glikson and Vickers, 2003) and consequent oceanic (sima crust-located) impact basins with diameters on a scale of several hundred kilometers.
The implications of these observations for the nature of the early Earth are inconsistent with strict uniformitarian geodynamic models based exclusively on plate tectonic processes. It is suggested the evolution of the early crust represents the combined effects of mantle-driven convection, modified plate tectonic regimes, and large extraterrestrial impacts which triggered deep faulting and adiabatic mantle melting. The latter resulted, in turn, in a feedback mechanism which temporally and spatially controlled the onset and loci of long term dynamic plate tectonic patterns.
A picture emerges of a post-3.8 Ga early Precambrian Earth, i.e. postdating the Late Heavy Bombardment of 3.9-3.8 Ga, which consisted of sialic (SiAl-dominated) continental nuclei composed of multiple superposed greenstone-granite cycles interspersed within extensive tracts of simatic (SiMg-dominated) oceanic crust. The latter included maria-like impact basins on scales of up to several hundred kilometer, i.e. similar in size to the lunar Mare Crisium impact basin (~3.2 Ga; Ds ~ 400 km) or even Mare Serenitatis (Ds ~ 600 km).


References:

Byerly, G.R., Lowe, D.R., 1994, Geochim. Cosmochim. Acta, 58, 3469-3486

Glikson, A.Y., Vickers, J., 2003, Geol. Surv. West Aust. Report

Kyte, F.T., Shukloyukov, A., Lugmair, G.W., Lowe, D.R., Byerly, G.R., 2003 Geology, 31, 283-286

Lowe, D.R., Byerly, G.R., Asaro, F., Kyte, F.T.1989, Science 245, 959-962

Lowe, D.R., Byerly, G.R., Kyte, F.T., Shukloyukov, A. Asaro, F., Krull, A., 2003, Astrobiology, 3, 7-48

Melosh, H.J., Vickery, A.M., 1991, Nature, 350, 494-497; Shukolyukov, A., Kyte, F.T., Lugmair, G.W., Lowe, D.R. and Byerly, G.R. (2000), Springer, Berlin, pp.
99-116

Simonson, B.M., Davies, D., Wallace, M., Reeves, S., Hassler, S.W., 1998, Geology, 26, p. 195-198



Karl E. Haisch Jr

University of Michigan


Circumstellar Disk Evolution in Young Stellar Clusters

Time when the process you describe started in the solar system: 200,000 yr

The error bar on the start time: 100,000 yr

Time when this process ended: 6 Myr

The error bar on the end time: 1 Myr

We report the results of the first sensitive infrared and millimeter continuum surveys of the young clusters NGC 1333, NGC 2071, NGC 2068, and IC 348 to obtain a census of the circumstellar disk fractions in each cluster. Our observations reveal that the variation in the fraction of detected millimeter sources from cluster to cluster is similar to the variation in the fraction of infrared sources for these clusters, implying that the inner and outer disks are coupled.


In addition, we conclude that our published estimation of disk lifetimes (t ~ 6 Myr) from infrared excesses provides accurate upper limits to the lifetimes of massive outer disks. This is the timescale for essentially all the stars in a cluster to lose their disks, and should set a meaningful constraint for the planet building timescale in stellar clusters. The implications of these results for current theories of planet formation are discussed.
Masahiko Honda

Research School of Earth Sciences, Australian National University


The origin and evolution of planetary atmospheres - implications from noble gases

Time the formation of the terrestrial atmosphere started: unknown

Time the formation of the terrestrial atmosphere finished: 100 Ma relative to the formation of solar system

Error bar: 40 Ma


The differences in noble gas elemental abundances between the Earth's atmosphere and the solar abundances lead to the recognition that the Earth's atmosphere was formed secondarily by extensive degassing of volatiles from the Earth's interior, rather than by directly acquiring a primary atmosphere from the surrounding solar nebula.

Models of degassing of volatiles from the Earth based on the differences of 40Ar/36Ar ratios in the Earth's atmosphere (=295.5; 40Ar produced from the decay of radioactive isotope 40K in the Earth and 36Ar is primordial) and in mantle-derived samples (>40,000) suggest that the Earth atmosphere was formed during a short period within ~100 million years of the formation of the solar system; namely by catastrophic degassing. Excess 129Xe, relative to the atmospheric 129Xe/130Xe ratio, observed in mantle-derived samples is believed to be attributable to the radioactive decay of the extinct nuclide 129I (half life 16 million years) once present in the Earth; this requires that the Earth's atmosphere must have separated from the mantle before all the 129I had decayed (another powerful argument in favour of early catastrophic degassing of the Earth).


The observation of primordial solar neon, distinctly different from present-day atmospheric neon, in mantle-derived samples implies that the Earth's atmosphere has not evolved in a closed system.  This can be explained by postulating that isotope fractionation occurred in the Earth's atmosphere as a consequence of hydrodynamic-escape processes, possibly associated with the rupture of the Moon, or, that volatile-rich meteoritic material accreted at a late stage in the Earth's formation.
Similarities between the noble gas elemental abundances of the atmospheres of the terrestrial planets (Venus, Earth and Mars), and between the neon isotopic compositions of the Earth's atmosphere and Mars-derived meteorites, suggests that insights to the formation of the Earth's atmosphere may be generally applicable to the atmospheres of the other inner "terrestrial-type" planets.

Ing-Guey Jiang

Institute of Astronomy, National Central University, Taiwan


The Eccentricity Outburst and Resonance Sweeping

Time when the process started in the solar system: 0 Myr

The error bar on the start time: 0.9 Myr

Time when this process ended: 1.0 Myr

The error bar on the end time: + 1.0 Myr, - 0.9 Myr
The dynamics of asteroids within planetary systems is studied and the role of proto-stellar discs is discussed. We found that the orbital eccentricities of test particles near the resonant region can be amplified significantly. The disc depletion could lead to the migration of resonant region, which would definitely affect the resulting observed dynamical properties of the asteroid belts for any planetary systems in general.

Ray Jayawardhana

University of Michigan


Timescales of Disk Evolution and Planet Formation
Most newborn stars are surrounded by disks of dust and gas. It is out of these disks that planetary systems form. Studies of disk evolution can provide valuable insight into the timescales and processes of planet formation. Recent observations at infrared and millimeter wavelengths of young stars spanning a range of ages suggest that their (inner) dusty disks evolve relatively rapidly, on timescales of 10 million years or less. I will review the current evidence and discuss the constraints on planet formation models.
Gareth Kennedy

Monash U., Australia


The Influence of a Binary Companion on Planetary Formation
The timescale for terrestrial planets, or giant planet cores, to form by accretion depends on the balance between excitation in the early planetesimal disk caused by self-gravitational interactions, and de-excitaton caused by inelastic collisions. However, since approximately 48% of local galactic field stars have binary companions, we investigate the disruption of this balance when a binary companion is included. The method used to study this problem removes the effect of the interaction between planetesimals, thus allowing the "tidal stirring" effect on the disk caused by the binary to be examined. A summary of results will be given from computer simulations investigating additional excitation caused by a binary companion, and the implications for planetary formation.

Warrick Lawson

UNSW@ADFA, Australia


Long-lived accretion in nearby T Tauri stars

Time when the process started in the solar system: 0 Myr

The error bar on the start time: 0.9 Myr

Time when this process ended: 1.0 Myr

The error bar on the end time: + 1.0 Myr, - 0.9 Myr
The nearest young stellar populations share a kinematic origin with the nearest OB-star population (the Oph-Sco-Cen association) and have inferred ages of 5-15 million years. These stars are prime targets for all early stellar and planetary evolution issues, including the issue of circumstellar disk longevity. Optical/infrared study finds a small fraction of these stars still possess inner disks and are undergoing active disk-star accretion at 10 Myr, a timescale comparable to that demanded by planet formation theory to grow Jovian planets to near their final masses.

Laurie A. Leshin(1) and Steven J. Desch(2)

(1) Geological Sciences/Meteorite Center, Arizona State University

(2) Physics and Astronomy, Arizona State University
Making Waterworlds:  The Importance of 26Al
In order to understand the possibility of discovering life elsewhere, we seek to explore factors that affect the likelihood of forming "waterworlds" like the Earth in other solar systems.  Here, we consider the effect of the astronomical setting of a forming solar system, and specifically its effect on the abundance of the short-lived radioisotope 26Al.  If the source of 26Al in our solar system and others is a nearby supernova, the essentially random distance to the supernova explosion sets a solar system's initial abundance of 26Al.  Recent models for the delivery of water to the forming terrestrial planets indicate that most of Earth's water was carried in by hydrated asteroids.  In solar systems with more initial 26Al, asteroids would be drier, and dry Earths would result. In fact, solar systems with less 26Al than our own are more likely, and this could result in much wetter Earths.  Clearly this is only one factor that could affect the habitability of an extrasolar Earth, but it demonstrates the need to bring together astronomers, planetary scientists, and geoscientists to consider which factors are likely to be the most critical to forming and sustaining life.

Kurt Liffman

Monash University & CSIRO


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