the molecular complex cepheus a/b presents within an area of a few square degrees a full palette of molecular clouds ranging from photodominated regions (pdrs) heated by the stars from the cep ob3 association, to quiescent molecular clouds. site of star formation activity, it is one of the clearest examples of 'contagious. star formation. its relatively small distance (700 - 800 pc) allows high spatial resolution observations and extinction measurements via star counts. its location (l= 110 deg, b= 2.5 deg) far outside the bright molecular ring and almost free of background contamination, makes it an ideal target for comparing in different types of clouds the dust distributions with the co and atomic c and h distributions. we propose to make a coordinated co-fir emission survey of a 1.5 deg x 1 deg area extending from the s155 hii region to the cep a, b, f and e molecular clouds. the entire area has already bean mapped in 12co (1-0) with the cfa 1.2 m telescope. we plan to re-observe it in the 12co (2-1) and 13co ines with the iram 30-m telescope. we also plan to search for embedded sources at the interface of s155 with the molecular cloud, around cep b, using isocam, and to map the cii 158 micron-m line emission in the same interface region. the aim of this multi-wavelength survey is to study the energy balance, to characterise the gas and dust properties in the different clouds, and to estimate the molecular gas mass via different tracers (12co, 13co, dust extinction, thermal dust emission..). the iso data, which at long wavelength will complement the iras data, will be crucial in this investigation. the cepheus molecular complex, observed at a distance of 3 mpc, would have an angular size of 4 arcsec, comparable to that of the giant molecular associations. observed in nearby galaxies with mm-wave interferometers (e.g. ic342, downes... et al. 1992). our study will help interpreting these observations.
Instrument
CAM01 , PHT32
Temporal Coverage
1996-12-31T11:23:39Z/1997-01-07T21:16:03Z
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.
