Investigation of meteor shower parent bodies using various metrics

Transcription

1 Faculty of Physics, Bucharest University Astronomical Institute, Romanian Academy Investigation of meteor shower parent bodies using various metrics B. A. DUMITRU1,2,3,4, M.BIRLAN2,3, A. NEDELCU3,2, M. POPESCU3,2 1- Institute of Space Science (ISS), Magurele, Romania 2- Paris Observatory, Paris, France 3- Astronomical Institute of Romanian Academy, Bucharest Observatory, Bucharest, Romania 4- Faculty of Physics, Bucharest University, Bucharest, Romania

2 ABSTRACT The present knowledge of meteor showers relate the small bodies of our Solar System as supply sources for the meteor. Both comets and asteroids are considered at the origin of meteor showers. The new paradigm of "active asteroids" reveal a large field of investigation in finding the relationships between asteroids and meteors. Processes like ejection and disaggregation at impacts, rotational instabilities, electrostatic repulsion, radiation pressure, dehydration stress followed by thermal fractures, sublimation of ices are at the origin of matter loss of asteroids. Our objective is to find genetic relationships between asteroids and meteor shower using metrics based on orbital elements. For this objective we selected three metrics (Southworth & Hawkins, Asher et al, Jopek respectively), and the recent MPC database and the more recent IAU meteor database shower. From our analysis, 41 of meteor showers have probabilities to be produced (or to be fuelled) by asteroids. Our sample of asteroids contains more than 1,000 objects, all of them belonging to the Near-Earth Asteroid population. Into our sample, we reproduce the association of 3200 Phaeton to Geminid meteor shower, as well as the association of 1991 AQ to Northern delta Capricornids. Some of our associations are puzzling while the results seem to diverge from the one of the literature. A systematic approach concerning the physical properties of our sample was performed and reinforced the link between asteroids and the associated meteor shower.

3 RATIONALE Our present knowledge is that at the base of meteor showers is found to small bodies of the solar system (comets and asteroids). The processes which produce the fragments for meteor showers are [D. Jewitt, H. Hsieh, J. Agarwal(2015)]: ejection and disaggregation at impacts rotational instabilities electrostatic repulsion radiation pressure dehydration stresses thermal fracture sublimation of ice The aim of this study was to determine the relationship between asteroids at Earth moving through meteoroid debris the origin of meteor streams.

4 METRICS Southworth and Hawkins (1963) Jopek (1993) Asher, Clube and Steel (1993) Orbital elements of an orbit (a semimajor axis, e - eccentricity, i - inclination, N - longitude of the ascending node, Π - perihelion distance) To obtain the possible parents of the meteor streams (A) with the help of the Dcriteria metrics listed above, we need to establish a limit value within the associated asteroid (B) having the probability to be a parent, D(A,B) < D C, were Dc is the maximum distance that can be considered a parent to that shower stream.

5 Threshold selection. (Left) Representation of medium associations objects per meteor shower vs associated meteor showers. (Right) Representation of medium associations objects per meteor shower vs D Cutoff. Analysis procedure IAU Minor Planet Data Center for asteroids, over 700,000 objects, February

6 Results 1086 associated asteroids to 41 meteors showers (see fig. 5) All associated asteroids have near earth orbits (see fig. 5)

7 IAU Meteor Data Center ( about 100 meteor showers, February 2016) [Jenniskens P. (2004)]. Data flow Albedo of known selected NEAs. There is an important fraction of low-albedo asteroids

8 The position of associated asteroids in the solar system, in a diagram of eccentricity vs semimajor axes. In the first representation we have all objects from the IAU Mineor Planet Center (all asteroids - grey), all established meteor showers (red) and planets from Mercury to Jupiter (green). The black rectangle represents an zoom were the used metrics found asteroids associated with meteor showers. This zoom is an representation where we have all the associated asteroids (1086 objects) by all metrics used (DACS - red, DSH- green, DH - blue) and the associated meteor shower (violet).) Conclusions 53 asteroids associated by all metrics, with high probability 320 asteroids associated by two metrics, medium probability 15% of the associated asteroids are PHA

9 Meteor showers associated by all metrics and the common associations. The high probability represents asteroids that were associated by all used metrics and medium probability represents the asteroids associated by two metrics. The asteroids that are underlined are associated to more then one meteor shower with high probability. Asteroids that are bold were associated with other meteor shower, but to medium probability. In this case the asteroid were left to high probability. In the case of asteroids that are italic were associated to more then one meteor shower at medium probability.