.RU

Session Time: 10/7/2010 1:30 PM - Session Title: Iapetus and Mimas


Session Time: 10/7/2010 1:30 PM



Session Number: 47



Session Title: Extrasolar Planetary Mission Highlights



Session Type: Plenary



Session Description: Sagan Award presented to Carolyn Porco (CICLOPS/Space Science Inst.), presented by Ann Druyan :30pm - 1:40pm



47.01: haracterizing Exoplanet Atmospheres



Author Block: Jonathan J. Fortney

1
1University of California, Santa Cruz.

Presentation Time:

10/7/2010 1:40 PM - 2:20 PM

Location:

Plenary Ballroom

Abstract:   

Forty years ago the first work on understanding the composition, infrared spectra, and temperature structure of the atmospheres of the solar system's giant planets was just getting underway. Now we are doing similar 1st-order reconnaissance and modeling to understand the atmospheres of exoplanets, whose categories include Jupiter-class, Neptune-class, and un-classifiable planets. One driving force behind this work is that as the data gathered becomes better, the prospect exists to understand the atmospheres of the solar system’s planets in the context of similar exoplanets. Over the past few years, planets that transit their parent stars, predominantly in short-period orbits, have allowed us the best access to information about exoplanetary atmospheres. Mostly thanks to the Spitzer and Hubble space telescopes, we have now been able to begin the first reconnaissance of these hot planets, some of which orbit their parent stars in less than one day. We have made initial attempts to classify the atmospheres of the Jupiter-class transiting planets in terms of the presence or absence of temperature inversions, but finding a satisfactory theory to explain the observations has been a challenge. The atmospheric characterization of "super Earth" atmospheres such as GJ 1214b is now underway, showing us a clear pathway towards characterizing even smaller planets.

47.02: oRoT : A Mid-Term status Report on the Exoplanets Transit Detection Programme



Author Block: Daniel Rouan

1
1Observatoire de Paris-Meudon, France.

Presentation Time:

10/7/2010 2:20 PM - 2:55 PM

Location:

Plenary Ballroom

Abstract.Abstract: 

CoRoT, the french-european satellite of high-precision photometry was put in operation early 2007 and the mission has recently been extended for 2.5 years. This mid-term milestone is a good occasion to make a status report on the extrasolar planets program which is based on the transit detection technique. After a brief description of CoRoT specifications and in-flight performances, a summary of the 15 discoveries of exoplanets and brown dwarves will be done, with emphasis on several specific cases, such as the small size Corot-7b object or the long period planet Corot-9b. The results will be also presented in terms of statistical analysis. Finally, the prospects for the extended period will be discussed in the light of the experience gained by the CoRoT team.

47.03: 

epler

Planet Detection Mission: Highlights of the First Results



Author Block: William J. Borucki

1, D. Koch 1, Kepler Science Team
1NASA Ames Research Center.

Presentation Time:

10/7/2010 2:55 PM - 3:30 PM

Location:

Plenary Ballroom

Abstract:   

An important step in discovering the extent of life in our galaxy is to determine the number of terrestrial planets in the habitable zone (HZ) of solar-like stars. The Kepler Mission is designed specifically to determine the frequency of terrestrial planets in the HZ. It was launched on March 6, 2009 and is now measuring the brightness variations of 150,000 solar-like stars to detect patterns of transits that provide the size of the planet relative to the star and its orbital period. Combining these measurements with ground-based spectroscopy fixes the stellar parameters, the planet radius, orbital semi-major axis, and the location relative to the HZ.
The first six weeks of data show the presence of hundreds of candidate planets, and thousands of eclipsing binary stars, and variable stars of amazing variety. Discoveries of five new exoplanets are shown and compared with known exoplanets with respect to mass, size, density, and orbital period. Over 750 planetary candidates found in the first year of data; with many smaller than Neptune.. The released data include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with near-resonant periods. Data for these discoveries were released in June. Examples of many of these discoveries and their distributions are presented and discussed.
. Support by the NASA Astrophysics Division is gratefully acknowledged.

Session Time: 10/7/2010 3:30 PM



Session Number: 13



Session Title: Near-Earth Asteroids, Dynamics, and Meteorites



Session Type: Poster



13.01:  Search for Vulcanoids Using STEREO Heliospheric Imager Data



Author Block: Andrew J. Steffl

1, N. J. Cunningham 2, A. L. Graps 1, D. D. Durda 1, S. A. Stern 1
1Southwest Research Institute, 2University of Nebraska-Lincoln.

Presentation Time:

10/7/2010 3:40 PM - 3:42 PM

Location:

Exhibit Hall

Abstract:   

Interior to the orbit of Mercury, between 0.07 and 0.21 AU, is a dynamically stable region where a population of asteroids, known as Vulcanoids, may reside. As seen from Earth, the Vulcanoid zone lies between 4-12 degrees from the sun, making observations difficult. The best previous search used data from the LASCO C3 coronagraph on the SOHO spacecraft to place an upper limit on the apparent brightness of any Vulcanoids of V=8.0, corresponding to an object diameter of ~55km. Here, we present results from our campaign to analyze data from the Heliospheric Imagers aboard NASA's two STEREO spacecraft for Vulcanoids transiting through the instrument’s field of view. At present, we have not detected any Vulcanoids, even though our search is sensitive to objects as small as approximately 5 km in diameter--nearly 100 times fainter than the SOHO search. These limits place significant constraints on the formation and evolution of the putative Vulcanoid population.

13.02: he Population of Natural Earth Satellites



Author Block: Mikael Granvik

1, J. Vaubaillon 2, R. Jedicke 3
1Univ. of Hawaii, 2Observatoire de Paris, France, 3University of Hawaii.

Presentation Time:

10/7/2010 3:42 PM - 3:44 PM

Location:

Exhibit Hall

Abstract:   

We present the first debiased size-frequency and orbit distributions for a steady-state population of temporary-captured, natural Earth satellites (NES) excluding the Moon. We use orbital integrations to estimate the capture probability as a function of orbital elements and utilize the steady-state near-Earth-object (NEO) model by Bottke et al. (2002) to estimate the steady-state population of NESs.
For much of the 20th century NESs other than the Moon were not discussed in their own right but mentioned in the published literature only as a population producing meteors that travel far in the Earth's atmosphere or as a population explaining shallow meteorite impacts. Only during the last two decades has a couple of these objects been detected in space; 1991 VG and 2006 RH120. The origin and evolution of 1991 VG, e.g., whether it is a man-made or a natural object, can be debated, but 2006 RH120 is certainly natural with an absolute magnitude H of about 29.9. To gain understanding of this little studied and barely detected population's origin and evolution, we try to answer questions such as: At any instant, how many objects are in temporary capture as a function of their size? What are the characteristics of their pre- capture geocentric trajectories and heliocentric orbits? What is the typical duration of the temporary capture? How many orbits do NESs typically complete around the Earth? What are the characteristics of their geocentric orbits?
We anticipate that the interest in this small and nearby population will increase in the future as NESs are easily accessible targets for proposed NEO sample-return missions. Their typically small sizes could allow us to bring back an entire asteroid with the benefit that, e.g., microscopic surface or near-surface effects such as space weathering and lightscattering could be studied on a pristine body in ground-based laboratories.

13.03: o-orbital Asteroids of Earth as Candidates for Asymmetric Impactors on the Moon



Author Block: Youngmin JeongAhn

1, R. Malhotra 1
1Univ. of Arizona.

Presentation Time:

10/7/2010 3:44 PM - 3:46 PM

Location:

Exhibit Hall

Abstract:   

The observed leading/trailing asymmetry of rayed lunar craters may be owed to impactors having lower average encounter velocity than that of the current model of Near Earth Objects [NEOs] (Ito and Malhotra 2010). We are investigating the possibility that currently undetected co-orbital asteroids of Earth may partially account for the missing low velocity impactors. First, we obtain the dynamical lifetimes of asteroids in the co-orbital region of Earth's orbit. We adopt the realistic model of the eight major planets of the solar system and examine a wide range of initial orbital parameters of Earth co-orbital asteroids: semi-major axis, eccentricity, inclination, and relative longitude; we compare our results with those of a previous study (Tabachnik and Evans 2000, Evans and Tabachnik 2002). Then, we trace the escaping objects from the co-orbital region and determine their impact velocity with the Moon. We confirm that these objects have typical impact velocities much lower than the average impact velocity of NEOs. We estimate the current co-orbital population that may account for the leading/trailing asymmetry of lunar rayed craters. We discuss mechanisms for the possible origin and re-supply of co-orbital asteroids and the role of hypothetical primordial co-orbitals on the lunar crater asymmetry.
This research is supported by NSF grant AST-0806828.

13.04: ow Delta-v Near Earth Objects: A Survey Of Suitable Targets For Space Missions



Author Block: Elisabetta Dotto

1, D. Perna 1, F. De Luise 2, F. Bernardi 3, M. A. Barucci 4, J. R. Brucato 5, A. Rossi 6, E. Perozzi 7, S. Fornasier 4, G. B. Valsecchi 3
1INAF-Osservatorio Astronomico di Roma, Italy, 2INAF-Osservatorio Astronomico di Collurania, Italy, 3INAF-IASF, Italy, 4LESIA-Observatoire de Paris, France, 5INAF-Osservatorio Astrofisico di Arcetri, Italy, 6CNR-ISTI, Italy, 7Telespazio, Italy.

Presentation Time:

10/7/2010 3:46 PM - 3:48 PM

Location:

Exhibit Hall

Abstract:   

In the last years, scientific and technological goals pushed space agencies to plan and launch space missions to Near Earth Objects (NEOs). In this respect, observational programs devoted to the study of the physical nature of NEOs are needed in support of such a future space mission.
Starting from the classical definition of "accessibility" of a celestial body in terms of the velocity change (delta-V) needed to realize a rendez-vous mission (e.g. orbiting around an object), it is possible to show that NEOs can be more accessible than the Moon or as difficult to reach as Jupiter and beyond.
Our survey is therefore devoted to the study of NEOs that are suitable targets for a future space mission, due to their low delta-V (and short mission duration).
The observations of NEOs with favorable accessibility from the Earth, is fundamental in the target selection process, in order to guarantee both technical feasibility and high scientific return.

13.05: ltra-low Delta-v Neos As Prime Nasa Targets



Author Block: Martin Elvis

1, J. C. McDowell 1, R. P. Binzel 2, J. Hoffman 2
1Harvard-Smithsonian CfA, 2MIT.

Presentation Time:

10/7/2010 3:48 PM - 3:50 PM

Location:

Exhibit Hall

Abstract.Abstract: 

Missions to near-Earth asteroids (NEOs) are key destinations in NASA's new "Flexible Path" approach. NEOs are also of interest for science, for the hazards the post, and for their resources. We examine the selection criteria for target NEOs for human exploration to define a set of "Potentially Visitable Objects" (PVOs). Ultra-low delta-v from LEO to NEO rendezvous is the primary criterion, as this choice doubles the payload to NEO. Choices for NEOs as human destinations are currently very limited. Only 5 of the 6699 known NEOs have delta-v <4km/s, 2/3 of typical LEO-NEO delta-v. Even these are small and hard to recover. Other criteria - long launch windows, a robust abort capability, and a safe environment for proximity operations - will further limit the list of PVOs. Potentially there are at least an order of magnitude more PVOs but, to find them all on a short enough timescale (before 2025) requires a dedicated survey in the optical or mid-IR, optimally from a Venus-like orbit because of the short synodic period for NEOs in that orbit, plus long arc determination of their orbits.

13.06: os Alamos Radiation Hydrocode Models of Asteroid Mitigation by an Internal Explosion



Author Block: Robert Weaver

1, C. Plesko 1, W. Dearholdt 1
1Los Alamos National Lab.

Presentation Time:

10/7/2010 3:50 PM - 3:52 PM

Location:

Exhibit Hall

Abstract:   

Mitigation of a potentially hazardous object (PHO) by a conventional or nuclear subsurface burst is considered. This intervention methodology has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts and deflection from shallow buried bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center and near the edge (mitigation) of such PHO models (1-10 Mton TNT equivalent), specifically for asteroid 25143 Itokawa. Parametric studies will be done on: the value of the source energy (from 1 Mton to 10 Mton), the parameters in the Steinberg-Guinan strength model used and the internal composition of the object from uniform composition to a “rubble pile” distribution. Specifically we are interested in assessing the optimum depth of burial and energy required to essentially disrupt and/or move the PHO and therefore mitigate the hazard. Recollection will be considered.

13.07: umerical and Laboratory Investigations of Regolith Dynamics



Author Block: Naomi Murdoch

1, P. Michel 2, C. Berardi 3, W. Losert 3, D. C. Richardson 3, B. Rozitis 4, K. J. Walsh 2, S. F. Green 4, T. de Lophem 4
1The Open University, PSSRI, United Kingdom and University of Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, France, 2University of Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, France, 3University of Maryland, 4The Open University, PSSRI, United Kingdom.

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