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Spins and Shapes of Potentially Hazardous Asteroids

Torppa, Johanna and Aksnes, Kaare and Dai, Z. and Grav, Tommy and Hahn, Gerhard and Laasko, T. and Lagerkvist, Claes-Ingvar and Muinonen, Karri and Niemelä, J. and Näränen, J. and Rickman, Hans and Virtanen, Jenni (2005) Spins and Shapes of Potentially Hazardous Asteroids. In: Bulletin of the American Astronomical Society, 37 (3), abstract477. American Astronomical Society. 37th DPS Meeting, 2005-09-04 - 2005-09-09, Cambridge, (UK). ISSN 0002-7537

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Official URL: http://www.aas.org/publications/baas/v37n3/dps2005/477.htm


Asteroids whose orbits lie close to that of the Earth (called near-Earth objects) are a threat to our planet. Though none of the known asteroids are currently on a collision course with the Earth, there is a class called potentially hazardous asteroids (PHA's) whose orbits may in a few tens of years be perturbed to make a collision possible. In such case, we should have thorough knowledge of the physical properties of these objects because, unlike most other natural disasters, such a hazard is in principle avoidable. Thus in the fall of 2003, a group of asteroid and comet researchers from the Nordic countries have set started an observing program called Nordic NEON (Nordic Near-Earth Object Network). Both photometric and astrometric observations of PHA's have been carried out since April 2004. Photometry is used for determining the spin state and shape of PHA's and astrometry for computing more accurate orbits. In this DPS meeting we will concentrate on the photometric part of the program. We use methods developed in the University of Helsinki for analysing both kinds of data. Spin state and convex shape solution are obtained using the convex inversion method described in [1] and information of the nonconvex shape features are obtained with the spherical harmonics method (Muinonen and Torppa, in preparation). For initial period estimation only a few nights of observations is usually enough, while pole and shape determination requires more abundant data. Previously observed photometric data exists for about 35 PHA's, but only an approximate period is known for most of these. Properties of well over 500 PHA's are totally unknown. So far we have obtained period estimates for 4 new PHA's, and improved spin and shape solution for 3 targets. A number of foundations and universities from all the participating countries have taken part in funding this project.

Document Type:Conference or Workshop Item (Poster)
Title:Spins and Shapes of Potentially Hazardous Asteroids
AuthorsInstitution or Email of Authors
Torppa, JohannaUniversity of Helsinki
Aksnes, KaareUniversity of Oslo
Dai, Z.University of Oslo
Grav, TommyUniversity of Hawaii
Laasko, T.University of Helsinki
Lagerkvist, Claes-IngvarUniversity of Uppsala
Muinonen, KarriUniversity of Helsinki
Niemelä, J.University of Helsinki
Näränen, J.University of Helsinki
Rickman, HansUniversity of Uppsala
Virtanen, JenniUniversity of Helsinki
Journal or Publication Title:Bulletin of the American Astronomical Society
Refereed publication:No
In ISI Web of Science:No
Page Range:abstract477
Milkey, Robert W.UNSPECIFIED
Publisher:American Astronomical Society
Event Title:37th DPS Meeting
Event Location:Cambridge, (UK)
Event Type:international Conference
Event Dates:2005-09-04 - 2005-09-09
Organizer:American Astronomical Society - Division for Planetary Sciences
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):W - Vorhaben Asteroiden und Kometen (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Deposited By: Dr.phil. Gerhard Hahn
Deposited On:01 Dec 2005
Last Modified:14 Jan 2010 20:14

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