the knowledge of the the physical properties of the dust inside cold condensations in a stage just before the collapse forming the protostellar cores, is a key for the understanding of star formation process and interstellar matter dynamics. in particular, the opacity value is a crucial parameter determined mainly by the dust grains absorptivity/emissivity law. the submillimeter balloon-borne experiment pronaos-spm, has been launched recently (september 22 - 23 1996). it has discovered extended cold condensations (t=12k, size from 0.1 to 1pc) in molecular cloud complexes such as orion a, rho-oph, m17, and a cold interstellar matter component inside cirrus clouds. this detection has been possible thanks to an unique photometric sensitivity around a few mjy/sr/hz^1/2. preliminary data processing shows that the grain emissivity changes between these extended cold condensations and the surrounding hotter regions. we propose to perform two kinds of observation toward the direction of the discovered new objects: (1) isophot mapping at 135 and 200 mu in order to increase the accuracy of the dust temperature determination, (2) full low resolution lws spectral observations in the direction of each typical extended cold condensation and in the surrounding hotter region. these spectra should be very efficient tools to investigate the matter accretion around the grains, inside cold condensation (shielded from uv radiation), and to compare the dust properties between cold cores inside stellar forming regions and cold condensations in diffuse medium. in particular, detection of spectral features could be crucial to: i) study the grains mantle composition and growing processes, ii) look for new carbon agregates such as those proposed by marty et al.(1994). furthermore and independent of modelling forecasts, the accurate knowledge of the emissivity/ absorptivity law (continuum and possible features) is a key parameter for ...the understanding of the physical properties of the extended cold condensations recently discovered with pronaos.
Instrument
LWS01 , PHT22 , PHT32
Temporal Coverage
1997-04-14T10:01:10Z/1997-08-16T08:11:53Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, 1999, Dust And Gas Properties Of Extended Cold Cores In The Ism A Study Of Dust Matter Inside Cold Cores, 1.0, European Space Agency, https://doi.org/10.5270/esa-z02s1qi
