Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation

Details Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation

2004-11-03

arxiv.org/abs/astro-ph/0411080v2

Astrophys.J. 623 (2005) 917-921

Astronomy and Astrophysics

Astrophysics

5 pages, 3 figures ; Accepted for publication in ApJ, scheduled for the April 2005, v623 2 issue

Scientific paper

10.1086/428648

We analyze the dynamical expansion of the HII region and outer photodissociation region (PDR) around a massive star by solving the UV and FUV radiation transfer and the thermal and chemical processes in a time-dependent hydrodynamics code. We focus on the physical structure of the shell swept up by the shock front (SF) preceding the ionization front (IF). After the IF reaches the initial Stromgren radius, the SF emerges in front of the IF and the geometrically thin shell bounded with the IF and the SF is formed. The gas density inside the shell is about 10-100 times as high as the ambient gas density. Initially the dissociation fronts expands faster than IF and the PDR is formed outside the HII region. Thereafter the IF and SF gradually overtakes the proceeding dissociation fronts (DFs), and eventually DFs are taken in the shell. The chemical composition within the shell is initially atomic, but hydrogen and carbon monoxide molecules are gradually formed. This is partly because the IF and SF overtake DFs and SF enters the molecular region, and partly because the reformation timescales of the molecules become shorter than the dynamical timescale. The gas shell becomes dominated by the molecular gas by the time of gravitational fragmentation, which agrees with some recent observations. A simple estimation of star formation rate in the shell can provide a significant star formation rate in our galaxy.

Affiliated with

Also associated with

No associations

Rating

Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-47761