Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.sao.ru/cats/~satr/RFSymp/abs/40_Zinchenko.pdf Дата изменения: Mon Oct 9 11:39:04 2006 Дата индексирования: Tue Oct 2 10:18:47 2012 Кодировка: Поисковые слова: внешние планеты

PHYSICAL AND CHEMICAL STRUCTURE OF HIGH MASS STAR FORMING REGIONS
I.I. Zinchenko Institute of Applied Physics of the Russian Academy of Sciences 46 Uljanov str., Nizhny Novgoro d 603950, Russia zin@appl.sci-nnov.ru In recent years we surveyed several tens of high mass star forming regions in various molecular lines and in millimeter wave continuum. Basic physical prop erties of detected clumps and molecular abundances were derived. One of the problems is a selection of the b est tracer of mass distribution. In particular, we found that in regions of high mass star formation the CS emission correlates well with the dust continuum emission and is therefore a go o d tracer of the total mass while the N2 H+ distribution is frequently very different. This is opp osite to their typical b ehavior in low-mass cores where a freeze-out plays a crucial role in the chemistry. The b ehavior of other high density tracers varies from source to source but most of them are closer to CS. Radial density profiles in massive cores are fitted by p ower laws with indices ab out -1.6, as derived from the dust continuum emission. The radial temp erature dep endence on intermediate scales is close to the theoretically exp ected one for a centrally heated optically thin cloud. The velo city disp ersion either remains constant or decreases from the core center to the edge. Several cores including those without known emb edded IR sources show signs of infall motions. They can represent the earliest phases of massive protostars. There are implicit arguments in favor of small-scale clumpiness in the cores. Acknow ledgements. The work was supp orted by the Russian Foundation for Basic Research grant 06-02-16317 and by the Program "Extended ob jects in the Universe" of the Russian Academy of Sciences.