The Journey of the Sun A Virtual Reality Simulation A.J. Hanson…

   The Journey of the Sun
 A Virtual Reality Simulation

A.J. Hanson and P.C. Frisch
  Computer Science, Indiana University
                  and
Department of Astronomy and Astrophysics
          University of Chicago

     AISRP 2000, Boulder, CO
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              OVERVIEW

Local Solar Environment Model: ISM, molec-
ular clouds, loops, stars, local fluff, heliosphere
Distance Editing Tool: 2D maps, point sources,
and absorption data  3D models
NASA Data: dust, plasma, atoms, ions
Implementations: CAVE, Tools, Cosmic Clock

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Big Picture of Local Solar Environment

Working inward from ~500pc:

  Local Bubble.
  Local Fluff.

  Heliosphere.



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Components of Solar Environment [See Figs]

 Interstellar clouds of gas and dust.
 Molecular clouds. H2 clouds traced by CO
 Supernova remnants. Radio Continuum Loops
 Stars and Associations. Massive stars, nearby
 stars, white dwarfs, and pulsars
 Local Fluff.
 Heliosphere. Heliopause, bow and term. shock

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       3D Modeling of Interstellar Matter

Synthesize the distribution of interstellar matter in
the local Solar environment out to ~500 pc.

   Absorption Data. Put distances on features in
   emission maps
   Emission Maps. Establish 2D positions and
   cloud types (neutral, warm ionized, molecular,...)
   3D Structure. From combining star distances
   with aborption data and emission maps
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      Cloud Types and Tracers

CNM/WNM. Warm and cold neutral matter (H0
21-cm emission; optical and UV absorption lines)
WIM. Warm ionized matter (H-alpha emission,
pulsar dispersion measure, UV absorption lines)
HIM. Hot ionized material (soft X-ray emission,
UV absorption lines)
Molecular Clouds. (CO emission)

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                Resources

NASA Data Sources. Need to select the useful
data from enormous quantity available.

Models and Data from Colleagues and Databases.

Distance Editing Tool. Combine data sources
for analysis.



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   Distance Editing Tool [Demo]

Multiple sources. Combine 2D maps, point
sources, and absorption line data  3D dis-
tance information
2D Data. Texture maps give context
Distance Data. Sources with known distances,
absorption line data
Sliding Tubes. Interactive manipulation of ab-
sorption data to deduce distances
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  Analysis Method: Sliding Tube

Sliding tube represents cloud thickness (inter-
stellar material absorbing starlight)

Texture maps on grid suggest the underlying
material (106-degree plasma, heated dust, neu-
tral H, molecular cloud).

Point sources: stars, etc, provide background
3D constraints on the 2D image data

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  Combining Multispectral Data

Dust.

­ Emission = infrared data (e.g. IRAS, DIRBE)
­ Absorption = color excess of stars

CNM. Cold neutral material

­ Emission = H0 21-cm
­ Absorption = stellar UV & optical absorption
  lines

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   Combining Multispectral Data, contd
WIM. Warm ionized material
­ Emission = H-alpha data, radio continuum (loops)
­ Absorption = absorp. lines, pulsar dispersion
WNM. Warm neutral material
­ Emission = H0.
­ Absorption = UV, optical absorption lines
HIM. Hot ionized material
­ Emission = soft X-ray background
­ Absorption = UV absorption lines in disk and
  halo stars
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                 Local Fluff

Absorption Line Data.
Column Densities: Use col. densities in Dis-
tance Editing Tool to find geom. of Local Fluff

Fine Structure. Determine geometry of cloudlets
in Local Fluff


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      Kinematics of Local Fluff

Interstellar Gas Flow velocity. Find system-
atic 3D motions

Cloudlet properties. Get kinematics of individ-
ual local cloudlets

Solar environment. Establish kinematics of Sun
relative to nearby cloudlets

Relative motions of nearby stars.

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                Heliosphere
Interaction of Solar System with the Local Fluff.

   Heliopause. (discontinuity between plasmas)
   Termination Shock. (solar wind goes subalfvenic)

   Bow Shock. (interstellar flow goes subsonic)



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    Interstellar medium and the
    Interplanetary Environment

Interstellar neutral gas.

Interstellar dust and micrometeorites.

Planetary magnetospheres.
Future: Solar cycle and time varying helio-
sphere.


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          Implementation Activities
Related work on interactive astrophysical visualization:
   Computer Science. Dagstuhl 2000 Workshop, Amster-
   dam Visualization Symposium, NSF/DoE Lake Tahoe Work-
   shop on Hierarchical Methods in Visualization.
   Adler Planetarium. Resource provider for "Sun-Earth
   Connection" show.
   "Cosmic Clock." 3-1/2 minute computer animation. One
   of 39 selected from 630 entries for Siggraph 2000 graph-
   ics conference. Cosmological causality and the Hubble
   expansion (physical vs comoving coordinates).

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               SUMMARY

Data sets. Assembling and analyzing unified
local galactic environment data sets.

Interactive systems. General tools for 3D anal-
ysis, CAVE applications for very large scales,
"Cosmic Clock" movie.

Future Work. Continue with new data sources
and analysis applications.

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