منابع مشابه
From forced collapse to H ii region expansion in Mon R2: Envelope density structure and age determination with Herschel
Context. The surroundings of H regions can have a profound influence on their development, morphology, and evolution. This paper explores the effect of the environment on H regions in the MonR2 molecular cloud. Aims. We aim to investigate the density structure of envelopes surrounding H regions and to determine their collapse and ionisation expansion ages. The Mon R2 molecular cloud is...
متن کاملInsights into the Carbon Chemistry of Mon R2
Aiming to learn about the chemistry of the dense PDR around the ultracom-pact (UC) H II region in Mon R2, we have observed a series of mm-wavelength transitions of C 3 H 2 and C 2 H. In addition, we have traced the distribution of other molecules, such as H 13 CO + , SiO, HCO, and HC 3 N. These data, together with the reactive ions recently detected, have been considered to determine the physic...
متن کاملThe H Ii Region of a Primordial Star
The concordance model of cosmology and structure formation predicts the formation of isolated very massive stars at high redshifts in dark matter dominated halos of 10 to 10M⊙. These stars photo-ionize their host primordial molecular clouds, expelling all the baryons from their halos. When the stars die, a relic H II region is formed within which large amounts of molecular hydrogen form which w...
متن کاملInterval Type-II Fuzzy H∞ Frequency Control for an Island Microgrid
Frequency control is one of the key parts for the arrangement of the performance of a microgrid (MG) system. Theoretically, model-based controllers may be the ideal control mechanisms; however, they are highly sensitive to model uncertainties and have difficulty with preserving robustness. The presence of serious disturbances, the increasing number of MG, varying voltage supplies of MGs, and bo...
متن کاملThe H Ii Region of the First Star
Simulations predict that the first stars in a ΛCDM universe formed at redshifts z > 20 in minihalos with masses of about 10M⊙. We have studied their radiative feedback by simulating the propagation of ionization fronts (I-fronts) created by these first Population III stars (M∗ = 15 − 500M⊙) at z = 20, within the density field of a cosmological simulation of primordial star formation, outward th...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1987
ISSN: 0074-1809
DOI: 10.1017/s0074180900095474