| 1. |
- Dahlgren, M, et al.
(author)
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A study of Hilda asteroids - V. Lightcurves of 47 Hilda asteroids
- 1998
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In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 133:2, s. 247-285
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Journal article (peer-reviewed)abstract
- The results of a photometric survey of Hilda asteroids are presented. We have obtained 224 lightcurves of 47 Hilda asteroids. A wide span of rotation periods have been found, ranging from 2.851 to 31 h. However, indications of rotation periods longer than
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| 2. |
- Dahlgren, M, et al.
(author)
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A study of Hilda asteroids - VI. Analysis of the lightcurve properties
- 1999
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In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 138:2, s. 259-267
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Journal article (peer-reviewed)abstract
- The lightcurves of 47 Hilda asteroids presented in Dahlgren et al, (1998, Icarus 133, 247-285) have been analyzed. The Hilda population has mean lightcurve amplitudes significantly larger than those of main-belt asteroids of similar sizes, This is due to
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| 3. |
- Davidsson, BJR
(author)
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Tidal splitting and rotational breakup of solid spheres
- 1999
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In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 142:2, s. 525-535
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Journal article (peer-reviewed)abstract
- A number of new expressions for the Roche limit are derived in order to investigate the splitting behavior of cometary nuclei when passing close to massive bodies. These expressions handle both tensile and shear failure, taking the radius, density, materi
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| 4. |
- Grun, E., et al.
(author)
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South-North and Radial Traverses through the Interplanetary Dust Cloud
- 1997
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In: Icarus. - : Elsevier BV. - 0019-1035. ; 129:2, s. 270-288
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Journal article (peer-reviewed)abstract
- Identical in situ dust detectors are flown on board the Galileo and Ulysses spacecraft. They record impacts of micrometeoroids in the ecliptic plane at heliocentric distances from 0.7 to 5.4 AU and in a plane almost perpendicular to the ecliptic from -79 deg to +79 deg ecliptic latitude. The combination of both Ulysses and Galileo measurements yields information about the radial and latitudinal distributions of micron- and sub-micron-sized dust in the Solar System. Two types of dust particles were found to dominate the dust flux in interplanetary space. Interplanetary micrometeoroids covering a wide mass range from 10^-16 to 10^-6 g are recorded mostly inside 3 AU and at latitudes below 30 deg. Interstellar grains with masses between 10^-14 and 10^-12 g have been positively identified outside 3 AU near the ecliptic plane and outside 1.8 AU at high ecliptic latitudes (>50 deg). Interstellar grains move on hyperbolic trajectories through the planetary system and constitute the dominant dust flux (1.5 x 10^-4 m^-2 sec^-1) in the outer Solar System and at high ecliptic latitudes. To compare and analyze the Galileo and Ulysses data sets, a new model is developed based on J. Geophys. Res. 98, 17029-17048, Divine's (1993, ``five populations of interplanetary meteoroids'' model. Both models describe the interplanetary meteoroid environment in terms of dust populations on distinct orbits. Taking into account the measured velocities and the effect of radiation pressure on small particles (described by the ratio of radiation pressure force to gravity, beta), we define four populations of meteoroids on elliptical orbits and one population on hyperbolic orbit that can fit the micrometeoroid flux observed by Galileo and Ulysses. Micrometeoroids with masses greater than 10^-10 g and negligible radiation pressure (beta = 0) orbit the Sun on low to moderately eccentric orbits and with low inclinations (<=30 deg). Populations of smaller particles with mean masses of 10^-11 g (beta = 0.3), 10^-13 g (beta = 0.8), and 5 x 10^-15 g (beta = 0.3), respectively, have components with high eccentricities and have increasingly wider inclination distributions with decreasing mass. Similarities among the orbit distributions of the small particle populations on bound orbits suggest that all are genetically related and are part of an overall micrometeoroid complex that prevails in the inner Solar System. The high-eccentricity component of the small particle populations may actually be beta-meteoroids which are not well characterized by our measurements. Our modeling suggests further that the interstellar dust flux is not reduced at Ulysses' perihelion distance (1.3 AU) and that it contributes about 30% of the total dust flux observed there.
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| 5. |
- Hahn, G, et al.
(author)
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The recent orbital history of periodic Comet P/Lagerkvist (1996 R2)
- 1999
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In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 140:2, s. 462-463
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Journal article (peer-reviewed)abstract
- Numerical integrations of 99 orbits centered on that of Comet P/Lagerkvist (P/1996R2) and of the original orbit were made 70 years backward in time and 200 years into the future. The integrations show that this comet, belonging to the quasi-Hildas (G. Tan
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| 6. |
- Kamel, L
(author)
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On the photometric indices of periodic comets
- 1996
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In: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 122:2, s. 428-431
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Journal article (other academic/artistic)abstract
- A statistical investigation of the photometric indices of periodic comets shows a mean of about 7.4 (sigma approximate to 7.6), a slight variation with heliocentric distance and a perihelion asymmetry in the distribution. (C) 1996 Academic Press, Inc.
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| 7. |
- Kamel, L
(author)
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The delta effect in the lightcurves of 13 periodic comets
- 1997
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In: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 128:1, s. 145-159
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Journal article (other academic/artistic)abstract
- A comparison of the lightcurves for 13 periodic comets at apparitions with close encounters with the Earth and nearby apparitions with larger geocentric distances shows evidence of a delta effect. (C) 1997 Academic Press.
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| 8. |
- Lagerros, JSV, et al.
(author)
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ISOPHOT polarization measurements of the asteroids (6) Hebe and (9) Metis at 25 mu m
- 1999
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In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 142:2, s. 454-463
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Journal article (peer-reviewed)abstract
- The subsurface thermal IR emission of asteroids becomes linearly polarized when scattered across the surface, The disk integrated mid-IR Stokes parameters are computed by extending the new thermophysical model by Lagerros (1996, Astron. Astrophys. 315, 62
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| 9. |
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| 10. |
- Magnusson, P, et al.
(author)
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Photometric observations and modeling of asteroid 1620 Geographos
- 1996
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In: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 123:1, s. 227-244
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Journal article (other academic/artistic)abstract
- Photometric observations of 1620 Geographos in 1993 and 1993 are presented and, in combination with previously published data, are used to derive models of Geographos, We estimate that the sidereal period of rotation is 0.21763860 +/- 0.00000003 days (5(h
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