Potential associations of Apollo asteroids with meteor streams are searched on the basis of the orbital parameters comparison. From all Apollo asteroids discovered through 1991 June those are only selected for further analysis whose orbits approach to less than 0.1 AU to the Earth's orbit. Their orbits are compared with precise photographic orbits of individual meteors from the Meteor Data Center in Lund. Results on the associations of asteroids with meteor streams are presented and discussed

Porubcan, V.

Stohl, Jan

Vana, R.

English

NASA Technical Reports Server

Asteroids, Comets, Meteors 1991,pp. 473476
Lunar and Planetary Institute, Houston, 1992
_"tl O- 70
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ON ASSOCIATIONS OF APOLLO ASTEROIDS WITH METEOR STREAMS
V. Porub6an I J. _tohl I and R Vana 2
i) Astronomical Institute, Slovak Academy of Sciences,
84228 Bratislava, Czech and Slovak Federal Republik
2) Department of Astronomy and Astrophysics, Comenius University
84215 Bratislava, Czech and Slovak Federal Republik
Abstract
Potential associations of Apollo asteroids with meteor streams
are searched on the basis of the orbital parameters comparison.
From all Apollo asteroids discovered through 1991 June those are
only selected for further analysis whose orbits approach to less
than 0.1 AU to the Earth's orbit. Their orbits are compared with
precise photographic orbits of individual meteors from the Meteor
Data Center in Lund. Results on the associations of asteroids with
meteor streams are presented and discussed.
Introduction
Since the time of the discovery of the asteroid 3200 Phaethon in
1983 and of its strong association with the Geminid meteor shower,
earlier suggestions of the association of meteoroid streams with
asteroids (cf. Sekanina, 1973, 19761 Drummond, 1982) have become
more substantiated. Recently an attempt was made to find out
asteroids-meteor streams associations on the basis of comparison
of individual radar orbits of meteors determined by the Adelaide
meteor orbit surveys with orbits of the Apollo asteroids (Olsson-
-Steel, 1988, 1990)• Several asteroids have been proposed as very
probable candidates for association with meteors. Similar search
with the mean orbits of the Cook's working list of meteor streams
lead Olsson-Steel to the same conclusions.
In the present paper a search for associations of asteroids with
meteors is carried out on the basis of comparison between the
orbits of asteroids and precise photographic meteor orbits
available from the IAU Meteor Data Center in Lund.
Data and the association search
Through 1991 June there have been 174 orbits of Apollo, Amor and
Aten asteroids available. Only those of them were included into
our analysis, which approach the orbit of the Earth to less than
O.i AU, their number being 90. For each of them the date of the
closest approach to the Earth was calculated, together with the
limiting ecliptical longitudes within which orbit of a particular
asteroid is closer to the Earth orbit than O.i AU. These
https://ntrs.nasa.gov/search.jsp?R=19930010034 2020-03-17T07:28:56+00:00Z
474 Asteroids, Comets, Meteors 1991
longitudes were than accepted as limits for search of association
of the particular asteroid with meteor orbits.
As a counterpart to the orbits of asteroids 3500 orbits of
individual meteors from the IAU Meteor Data Center in Lund were
searched. Orbit of each asteroid was compared with all meteor
orbits falling within the longitudinal limits of 0.I AU. For
finding the asteroid-meteors associations the Southworth-Hawkins'
D-criterion was applied (Southworth and Hawkins, 1963). As a
limit for the orbital match the value D = 0.25 was taken into
account, though for the association a stronger limit D = 0.20 was
only accepted.
Among the 147 Apollo, Amor and Aten asteroi4s there were 84 cases
for which no meteor orbit has been foun_ matching their orbits
within the limit of D = 0.25; for another 3! aster0ids there were
no meteor orbits found fulfilling the associa£ion criterion D =
= 0.20. We have thus 59 asteroids, for which the association with
meteor streams can be accepted with various degree of probability.
Asteroids-meteors associations and their discussion
In Table 1 general results of the search are presented in a
concise form. Asteroids are somewhat arbitrarily divided into 4
groups according to the number of meteor orbits N.20 and N.25
matched to the orbits of particular asteroids within the limits,
D = 0.20 and D = 0.25, respectively. The groups are chosen as
follows: I - N.20_8 or N.25 _13; II - N.20_6 or N.25_9; III -
N.20 _4 or N.25_ 6; IV - N.20_ 3. Total numbers of asteroids
Table i. Associations of asteroids with meteors
Number of
Group asteroids Asteroids
I. 14 (Cf. Table_ 2)
High 13P, iS
II. 13
Medium 8P, 5M
1950 DA, 1983 LC, 1991 JX, 1 1991 FB, 1987 SF3,
4197 (1982 TA), 2061 Anza, 1990 UQ, 1990 MF,
3361 Orpheus, 3908 (1980 PA), 3757 (1982 XB),
1984 KB
III. 13
Low 12P, IM
IV. 19
Very low 15P, 2M
2T
1989 UP, 4486 Mithra, 1917 Cuyo," 1988 EG,
1989 DA, 4450 Pan, 1990 TGI, 4515 (1979 VA),
1990 UN, 1989 JA, 1988 VP4, Hermes
..... • :_ \
1566 Icarus, 1862 Apollo, 2101 Adonis, 2340
Hathor, 2608 Seneca, 4034 (1986 PA), 4183
(1959 LM), 4581 (1989 FC), 4769 (1989 PB),
1983 TF2, 1987 OA, 1988 XB, 1989 QF, 1989 uQ,
1989 UR, 1990 SP, 1990 SS, 1991 GO, 1991 JR
Asteroids, Comets, Meteors 1991 475
falling into each group is given in Table i, Col. 2, together
with following specification of the asteroids: P-A_ollo, M-Amor,
T-Aten. The asteroids underlined have V G <10 km s .
Group I with the largest number of meteor orbits associated with
the asteroids is presented in Table 2 in more details. For each
asteroid following data are given: _r • - minimum distance of
the asteroidal orbit from the Earth or_ in AU, Date - the date
at which Ar . occurs, At - number of days when _r < O.i AU,
mln .
V_ - the geocentrlc veloclty of the asteroid corresponding to
I_ ....
r . , _ - Oeclinatlon of the expected radiant, N - total number
of _eor orbits within At, Nsh - number of meteor orbits
belonging to various showers as was determined be original
authors of the orbits, N.25 and N.20 - number of meteor orbits
associated with the asteroid within the limits D = 0.25 and 0.20,
respectively.
As was expected, the association of 3200 Phaethon with meteors,
in this case belonging to the Geminid shower, is the most
prominent. On the other hand, there are several other asteroids,
for which the number of matched meteors is much higher than might
be expected from random coincidences. They include asteroids
which had been proposed by several authors as being associated
with the Taurid meteor complex (5025 P-L, 2201 Oljato, 4197-1982
TA, 1984 KB) or with some minor showers (3671 Dionysius-1984 KD -
- THerculids, 1983 LC - Scorpiids, 1917 Cuyo - _Cygnids, 2061
Anza - Northern & Aquarids, 1950 DA - May Ursids, 3757-1982 XB -
- _Leonids, 1986 JK - Lybrids etc.). Closer inspection of
individual meteor orbits found to be matched with the orbits of
asteroids reveals other close associations of asteroids with known
meteor showers. Such is the case with the Delta Arietids (Kronk,
1988) which we suppose to be associated with 1990 HA showing
moreover that the activity of this minor shower extends from
November 26 till December 15 at least. Some of the asteroids
Table 2. Most probable associations of asteroids with meteors
Asteroid Armi n Date At V G _ N Nsh N.25 N.20
3200 Phaethon 0.025
4179 Toutatis 0.007
5025 P-L 0.082
1990 HA 0.062
3671 Dionysius 0.029
1989 VB 0.016
1986 JK 0.007
1990 OS 0.009
1991 BA 0.001
1990 UA 0.O12
4660 1982 DB 0.021
1980 AA 0.054
2201 Oljato 0.009
1988 TA 0.026
14 Dec 6 33.6 +32 312 212 210 203
24 Sep 58 11.9 -14 639 133 32 18
8 Nov 6 28.5 +24 81 28 26 15
4 Dec 20 15.9 +ii 437 242 23 14
17 Jun 40 11.2 +33 186 2 15 Ii
i0 Oct 86 6.4 -34 905 194 14 i0
4 Jan 49 13.4 -9 211 3 13 10
15 Aug 67 9.6 -25 1349 684 14 9
17 Jan 21 18.0 +19 83 3 i0 9
18 May 28 14.8 -14 iii 1 12 8
ii Dec 59 6.3 +23 696 329 19 7
i0 Jan 56 5.2 +32 527 247 15 7
21 Dec 17 20.2 +20 305 180 13 7
13 May 31 12.8 -20 137 14 14 6
476 Asteroids, Comets, Meteors 1991
from Groups I-III are included in the Drummond's associations
I-IV (Drummond, 1991).
It should be emphasized that the number of meteor orbits matched
to the orbit of an asteroid by itself is not a sufficient measure
of the reality of an association. There are several factors by
which this number can be overestimated (random coincidences) or
underestimated (especially low geocentric velocity which can
reduce the observed number of meteors to 1-2 orders).Confirmation
or refusal of the reality of the proposed associations demands
therefore a careful elimination of all these effects.
The research was supported by the Slovak Academy of Sciences Grant
493/1991.
References
Drummond J.D. (1982) Theoretical meteor radiants of Apollo, Amor
and Aten asteroids. Icarus, 49, 143-153.
Drummond J.D. (1991) Earth-approaching asteroid streams, icarus,
89, 14-25. _ _ - _ ......
Kronk G.V. (1988) Meteor showers: A Descriptive Catalog, Enslow
Publ., 296 pp.
Olsson-Steel D. (1988) Identification of meteoroid streams from
Apollo asteroids in the Adelaide radar orbit surveys. Icarus,
75, 64-96.
Olsson-Steel D. (1990) Apollo asteroid-related meteoroid streams,
In Asteroids, Comets, Meteors III (C.-I. Lagerkvist, M. Rickman,
B.A. Lindblad, and M. Lindgren, eds.), pp. 159-162. Uppsala
Universitet, Uppsala.
Sekanina Z. (1973) Statistical model of meteor streams. III.
Stream search among 19303 radio meteors. Icarus, i_88, 253-284.
Sekanina Z. (1976) Statistical model of meteor streams. IV. A
study of radio streams from the synoptic year. Icarus, 2_/7,265-
-321.
Southworth R.B., and Hawkins G.S. (1963) Statistics of meteor
streams. Smithson. Contr. Astrophys., 7, 261-285.


On associations of Apollo asteroids with meteor streams

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