Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions

Details Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions

2009-02-20

arxiv.org/abs/0902.3679v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

13 pages, 6 eps figures, MN Latex v2.2, accepted for publication in MNRAS

Scientific paper

10.1111/j.1365-2966.2009.14598.x

In general, HII regions do not show clear signs of self-enrichment in products from massive stars (M > 8 M_sun). In order to explore why, I modeled the contamination with Wolf-Rayet star ejecta of metal-poor (Z=0.001) HII regions, ionised either by a 10^6 M_sun cluster of coeval stars (cluster 1), or a cluster resulting from continuous star formation at a rate of 1 M_sun yr^-1 (cluster 2). The clusters have Z=0.001 and a Salpeter initial mass function (IMF) from 0.1 to 120 M_sun. Independent one dimensional constant density simulations of the emission-line spectra of unenriched HII regions were computed at the discrete ages 1, 2, 3, 4, and 5 Myr, with the photoionisation code CLOUDY, using as input, radiative and mechanical stellar feedbacks predicted by the evolutionary synthesis code STARBURST99. Each HII region was placed at the outer radius of the adiabatically expanding superbubble of Mac Low and McCray (1988). For models with thermal and ionisation balance time-scales of less than 1 Myr, and with oxygen emission-line ratios in agreement with observations, the interior of the superbubble and the HII region were uniformly and instantaneously polluted with stellar ejecta predicted by STARBURST99. I obtained a maximum oxygen abundance enhancement of 0.025 dex, with cluster 1, at 4 Myr. It would be unobservable.

Affiliated with

Also associated with

No associations

Rating

Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions 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 Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Predictions of the extent of self-enrichment in oxygen of giant metal-poor HII regions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-370401