From: Amara Graps (amara@amara.com)
Date: Mon Jan 28 2002 - 11:04:50 MST
From: Eugene Leitl <Eugene.Leitl@lrz.uni-muenchen.de>, Sun, 27 Jan 2002
>No, just our solar system. There is vigorous (albeit
>assymetrical) material exchange within the inner solar system through
>impact ejecta, there's zero interstellar pebble capture, however. Dust is
>too small, and travels too long to be fried thoroughly. Hence, stellar
>systems are probably mutually isolated petri dishes.
What ?
Interstellar dust/micrometeoroids is absolutely detected in the
inner Solar System, to, at least, near Earth. Some of it falls to Earth.
On the flip side, a tiny portion of our Solar System dust escapes
the Solar System.
'We' are not isolated bubbles. Other nearby stars are not isolated
from 'Us', either.
Did I misunderstand your above statement, Eugene?
Amara
==========Some IS Dust References=======================================
Title: Discovery of Jovian dust streams and interstellar
grains by the ULYSSES spacecraft
Authors: Grun, E.; Zook, H. A.; Baguhl, M.; Balogh, A.;
Bame, S. J.; Fechtig, H.; Forsyth, R.; Hanner, M. S.;
Horanyi, M.; Kissel, J.; Lindblad, B.-A.;
Linkert, D.; Linkert, G.; Mann, I.;
McDonnell, J. A. M.; Morfill, G. E.; Phillips, J. L.;
Polanskey, C.; Schwehm, G.; Siddique, N.;
Staubach, P.; Svestka, J.; Taylor, A.
Journal: Nature (ISSN 0028-0836), vol. 362, no. 6419, p.
428-430.
Publication Date: 04/1993
Abstract
Within 1 AU from Jupiter, the dust detector aboard the Ulysses
spacecraft during the flyby on February 8, 1992 recorded periodic bursts
of submicron dust particles with durations ranging from several hours to
two days and occurring at about monthly intervals. These particles
arrived at Ulysses in collimate streams radiating from close to the
line-of-sight direction to Jupiter, suggesting a Jovian origin for the
periodic bursts. Ulysses also detected a flux of micron-sized dust
particles moving in high-velocity retrograde orbits. These grains are
identified here as being of interstellar origin.
----------
Title: Radar measurements of very high velocity meteors
with AMOR
Authors: Taylor, A. D.; Baggaley, W. J.; Bennett, R. G. T.;
Steel, D. I.
Journal: Planetary and Space Science (ISSN 0032-0633), vol.
42, no. 2, p. 135-140
Publication Date: 02/1994
Abstract
The Christchurch (New Zealand) meteor radar AMOR (Advanced Meteor Orbit
Radar) has yielded about 1% of meteoroids having an atmospheric speed in
excess of 100 km/s. This indicates an influx of particles that is well
above the heliocentric parabolic limit for closed orbits. The evidence
for these extremely high Earth-encounter speeds comes from meteor echo
timing and ionization height characteristics. It is shown that aliasing
association with a finite radar sampling rate imposes an upper limit on
the atmospheric speeds avaliable from echo diffraction characteristics.
The possibility of an interstellar source as evidenced by the
heliocentric radiant distribution is discussed.
----------
Title: South-North and Radial Traverses through the
Interplanetary Dust Cloud
Authors: Grun, E.; Staubach, P.; Baguhl, M.; Hamilton, D. P.;
Zook, H. A.; Dermott, S.; Gustafson, B. A.;
Fechtig, H.; Kissel, J.; Linkert, D.; Linkert, G.;
Srama, R.; Hanner, M. S.; Polanskey, C.; Horanyi, M.;
Lindblad, B. A.; Mann, I.; McDonnell, J. A. M.;
Morfill, G. E.; Schwehm, G.
Journal: Icarus, Volume 129, Issue 2, pp. 270-288.
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.
----------
Title: The Mass Distribution of Interstellar Dust Grains
from In Situ Detections
Authors: Landgraf, M.; Grün, E.; Frisch, P. C.
Affiliation: AA(NASA/Johnson Space Center),
AB(Max-Planck-Institut f. Kernphysik Heidelberg),
AC(University of Chicago, Astronomy Department)
Journal: American Astronomical Society Meeting 193, #65.21
Publication Date: 12/1998
Abstract
Solid interstellar matter in the form of dust has been detected in the
solar system. We present our findings based on data collected with the
dust detectors on-board the Ulysses and Galileo spacecraft. The mass
distribution of interstellar dust is also determined by the wavelength
dependence extinctio of star light along lines of sight through the
diffuse interstellar medium. In a reasonable mass-range the mass
distribution of in situ detections is compatible with a dust population
governed by grain-grain collisions. Compared to mass distributions
determined by fitting the extinction-curve, the in situ detections
contain large grains with masses above 10<SUP>-13</SUP> g. The large
grains contribute much to the total mass of heavy elements in the
interstellar medium surrounding the sun and thus effectively change the
elementary composition of this medium.
----------
Title: Heavy Elements in the LIC -- Results from In Situ
Measurements of Interstellar Dust
Authors: Landgraf, M.; Gruen, E.
Affiliation: Max-Planck-Institut fuer Kernphysik Heidelberg
Journal: Astronomische Gesellschaft Meeting Abstracts,
Abstracts of Contributed Talks and Posters presented
at the Annual Scientific Meeting of the
Astronomische Gesellschaft at Heidelberg, September
14--19, 1998, poster #P13
Publication Date: 00/1998
Abstract
The in situ detection of interstellar dust-grains by the Ulysses and
Galileo spaceprobes gives us the opportunity to get information about
the contribution of interstellar dust to the heavy elements in the local
interstellar cloud (LIC). We find that despite the fact that the
gas-phase of the LIC has one of the lowest heavy element depletions
compared to other regions in the diffuse interstellar medium its dust
content in terms of mass is relatively high. As a consequence the total
element abundance of elements heavier than He in the LIC considering the
dust- plus the gas-phase is higher compared with any cosmic reference
abundance. We conclude that the local interstellar medium is
inhomogeneous, not only in density but also in composition, at least on
small length-scales.
----------
Title: Initial measurements with the dust detector onboard
Cassini
Authors: Srama, R.; Graps, A.; Gruen, E.; Helfert, S.;
Kempf, S.; Krueger, H.; CDA-dust-science Team
Affiliation: AF(Max-Planck-Institut fuer Kernphysik)
Journal: American Astronomical Society, DPS meeting #31,
#40.06
Publication Date: 09/1999
Origin: AAS
Abstract
During 85 days of operation CDA (DOY 84 to DOY 169, 1999) recorded 33
highly reliable impact events including one impact with a high quality
mass spectrum and 5824 noise events. The impact rate during the inner
planetary cruise is compared with the calculated count rates of the
Divine-Staubach model. During approach to th Sun, a slight increase of
the CDA count rate from about 2 impacts per week to 3 impacts per week
was observed. According to the model, before Venus 2 encounter until
DOY 140, interstellar dust flux tops the interplanetary dust flux.
After that time, interplanetary dust should be the dominant component
in the CDA measurements. The observed impact rate supports this picture
although the measured impact rate is somewhat lower than the combined
interstellar plus interplanetary model flux but higher than the
interplanetary flux alone. Therefore, the measurements suggest that a
significant portion of the interstellar dust flux reaches the region
inside the Earth's orbit.
----------
Title: The Interstellar Cloud Surrounding the Solar System
Authors: Frisch, P. C.
Journal: in "Cosmic Winds and the Heliosphere", University of
Arizona Press pp. 733--758 Eds. J.R. Jokipii, C.P.
Sonett, M.S. Giampapa
Publication Date: 00/1997
Abstract
Ultraviolet spectral data of nearby stars indicate that the cloud
surrounding the solar system has an average neutral density n(HI)~0.1
cm<SUP>-3</SUP>, temperature ~6800 K, and turbulence ~1.7 km/s.
Comparisons between the anomalous cosmic ray data and ultraviolet data
suggest that the electron density is in the range n(e-)~0.22 to 0.44
cm<SUP>-3</SUP>. This cloud is flowing past the Sun from a position
centered in the Norma-Lupis region. The cloud properties are consistent
with interstellar gas which originated as material evaporated from the
surfaces of embedded clouds in the Scorpius-Centaurus Association, and
which was then displaced towards the Sun by a supernova event about 4
Myrs ago. The Sun and surrounding cloud velocities are nearly
perpendicular in space, and this cloud is sweeping past the Sun. The
morphology of this cloud can be reconstructed by assuming that the cloud
moves in a direction parallel to the surface normal. With this
assumption, the Sun entered the surrounding cloud 2000 to 8000 years
ago, and is now about 0.05 to 0.16 pc from the cloud surface. Prior to
its recent entry into the surrounding cloud complex, the Sun was
embedded in a region of space with average density lower than 0.0002
cm<SUP>-3</SUP>. If a denser cloud velocity component seen towards alpha
Cen A,B is real, it will encounter the solar system within 50,000 yr.
The nearby magnetic field seen upwind has a spatial orientation that is
parallel to the cloud surface. The nearby star Sirius is viewed through
the wake of the solar system, but this direction also samples the
hypothetical cloud interface. Comparisons of anomalous cosmic ray and
interstellar absorption line data suggest that trace elements in the
surrounding cloud are in ionization equilibrium. Data towards nearby
white dwarfs indicate partial helium ionization,
N(N(HI)(/N(HeI)>~13.7, which is consistent with pickup ion data
within the solar system if less than 40% hydrogen ionization occurs in
the heliopause region. However, the white dwarfs may sample additional
ionized gas beyond the cloud surrounding the solar system.
==========More References===============================================
Query Parameters on NASA ADS:
Authors: BAGGALEY, W; BAGUHL, M; FRISCH, P;
GRUEN, E; LALLEMENT, R; LANDGRAF, M; M WITTE;
TAYLOR, A
Start date: 01/1992
End date: 02/2002
Selected Results:
------------------
Title: Discovery of interstellar dust entering the Earth's
atmosphere
Authors: Taylor, A. D.; Baggaley, W. J.; Steel, D. I.
Journal: Nature, vol. 380, p. 323-325 (1996).
Publication Date: 00/1996
------------------
Title: Electromagnetic Escape of Dust from the Solar System
Authors: Hamilton, D. P.; Grun, E.; Baguhl, M.
Journal: Physics; chemistry; and dynamics of interplanetary
dustAstronomical Society of the Pacific Conference
Series; Proceedings of the 150th colloquium of the
International Astronomical Union held in
Gainesville; Florida; USA; 14-18 August 1995; San
Francisco:Astronomical Society of the Pacific (ASP
104); |c1996; edited by Bo A. S. Gustafson and
Martha S. Hanner, p.31
Publication Date: 00/1996
------------------
Title: The Flux of Interstellar Dust Observed by ULYSSES
and Galileo
Authors: Baguhl, M.; Grun, E.; Hamilton, D. P.; Linkert, G.;
Riemann, R.; Staubach, P.; Zook, H. A.
Journal: The High Latitude Heliosphere. Proceedings of the
28th. ESLAB Symposium, held in Friedrichshafen,
Germany, April 19-21, 1994. Editor(s), R.G. Marsden;
Publisher, Kluwer Academic Publishers, Dordrecht,
The Netherlands, Boston, Massachusetts, 1995. LC #:
QB529 .E85 1994. ISBN #: 0792332296., p.471
Publication Date: 00/1995
------------------
Title: Galactic Dust Measurements Near Earth
Authors: Grün, Eberhard; Krüger, Harald; Srama, Ralf;
Colangeli, Luigi; Landgraf, Markus; Horanyi, Mihaly;
Kissel, Jochen; Svedhem, Hakan
Journal: Astronomische Gesellschaft Abstract Series, Vol. 17.
Abstracts of Contributed Talks and Posters presented
at the Annual Scientific Meeting of the
Astronomische Gesellschaft at Bremen, September
18-23, 2000.
Publication Date: 00/2000
------------------
Title: Aspects of the mass distribution of interstellar
dust grains in the solar system from in situ
measurements
Authors: Landgraf, M.; Baggaley, W. J.; Grün, E.;
Krüger, H.;
Linkert, G.
Journal: Journal of Geophysical Research, Volume 105, Issue
A5, May 1, 2000, pp.10343-10352
Publication Date: 05/2000
------------------
Title: Advanced Meteor Orbit Radar observations of
interstellar meteoroids
Authors: Baggaley, W. Jack
Journal: Journal of Geophysical Research, Volume 105, Issue
A5, May 1, 2000, pp.10353-10362
Publication Date: 05/2000
------------------
Title: Meteoroid Orbital Characteristics by Radar
Surveilence
Authors: Baggaley, W. J.
Journal: Earth, Moon and Planets, v. 71, p. 85-97.
Publication Date: 11/1995
------------------
Title: The Harvard Radio Meteor Project velocity
distribution reappraised.
Authors: Taylor, A. D.
Journal: Icarus, vol. 116, p. 154-158 (1995).
Publication Date: 07/1995
------------------
Title: Asymmetries in the natural meteoroid population as
sampled by LDEF
Authors: McBride, N.; Taylor, A. D.; Green, S. F.;
McDonnell, J. A. M.
Journal: Planetary and Space Science v. 43, p. 757-764
Publication Date: 06/1995
------------------
Title: Dust particles beyond the asteroid belt--a study
based on recent results of the ULYSSES dust
experiment
Authors: Mann, I.; Grun, E.
Journal: Planetary and Space Science v. 43, p. 827-832
Publication Date: 06/1995
------------------
Title: Characteristics of Nearby Interstellar Matter
Authors: Frisch, Priscilla C.
Journal: Space Science Reviews, v. 72, p. 499-592.
Publication Date: 04/1995
------------------
************************************************************************
Amara Graps, PhD | Max-Planck-Institut fuer Kernphysik
Heidelberg Cosmic Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY
Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps
************************************************************************
"We came whirling out of Nothingness scattering stars like dust." --Rumi
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