SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 2 - January 27, 2006

90 ASTROPHYSICS
Includes cosmology; celestial mechanics; space plasmas; and interstellar and interplanetary gases and dust.

20060002737 Lawrence Livermore National Lab., Livermore, CA USA

Next Generation Microlensing Search: SuperMacho

Drake, A. J.; Becker, A. C.; Clocchiati, A.; Cook, K. H.; Covarrubias, R.; Oct. 27, 2003; 14 pp.; In English Report No.(s): DE2005-15013810; UCRL-PROC-200594; No Copyright; Avail.: Department of Energy Information Bridge

Past microlensing experiments such as the MACHO project have discovered the presence of a larger than expected number of microlensing events towards the Large Magellanic Cloud (LMC). These events could represent a large fraction of the dark matter in the halo of our Galaxy, if they are indeed due to halo lenses. However, the locations of most of the lenses are poorly defined. The Super Macho project will detect and follow up approx. 60 microlensing events toward the LMC over the next 5 years. The expected discovery of a number of microlensing events exhibiting special properties due to binarity, etc., will allow us to better determine the location and nature of the lenses causing the LMC microlensing events. NTIS

Galactic Structure; Gravitational Lenses

20060002963 Lawrence Livermore National Lab., Livermore, CA USA

Stellar Opacity

Rogers, F. J.; Iglesias, C. A.; Nov. 07, 1999; 26 pp.; In English Report No.(s): DE2005-15013183; UCRL-JC-137066; No Copyright; Avail.: Department of Energy Information Bridge

As long ago as 1926 Eddington identified opacity as one of two clouds obscuring stellar model calculations: the source of stellar energy being the other.

At that time it was thought that bound-bound absorption was not a significant source of opacity.

It was 40 years later that Cox and Stewart included spectral lines in opacity calculations.

This led to opacity increases exceeding a factor of three at some temperature-density conditions.

These enhanced opacities greatly improved the quality of stellar models.

Even so, several properties of stars known to be sensitive to opacity resisted explanation. NTIS

Opacity; Stars; Stellar Models

20060002965 Lawrence Livermore National Lab., Livermore, CA USA

Interaction of Supernova Reminants with Interstellar Clouds: Experiments on the Nova Laser

Klein, R. L.; Budil, K. S.; Perry, T. S.; Bach, D. R.; Apr. 18, 2002; 52 pp.; In English Report No.(s): DE2005-15013481; UCRL-ID-148071; No Copyright; Avail.: National Technical Information Service (NTIS)

The interaction of strong shock waves, such as those generated by the explosion of supernovae with interstellar clouds, is a problem of fundamental importance in understanding the evolution and the dynamics of the interstellar medium (ISM) as it is disrupted by shock waves. Here we present the results of a series of Nova laser experiments investigating the evolution of a high density sphere embedded in a low density medium after the passage of a strong shock wave, thereby emulating the supernova shock-cloud interaction. The Nova laser was utilized to generate a strong (-Mach 10) shock wave that traveled along a miniature beryllium shock tube, 750 pm in diameter, filled with a low-density plastic emulating the ISM. Embedded in the plastic was a copper microsphere (100 pm in diameter) emulating the interstellar cloud. The morphology and evolution as well as the shock wave trajectory were diagnosed via side-on X-ray radiography. NTIS

Lasers; Supernovae

Source: NASA