The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe

Details The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe

2007-07-29

arxiv.org/abs/0707.4288v2

Astronomy and Astrophysics

Astrophysics

14 pages, 4 figures, accepted to MNRAS

Scientific paper

10.1111/j.1365-2966.2008.13435.x

In this work we present the first spectroscopic results obtained with the Southern African Large Telescope (SALT) telescope during its perfomance-verification phase. We find that the Sagittarius dwarf spheroidal galaxy (Sgr) Sgr contains a youngest stellar population with [O/H] -0.2 and age t>1 Gyr, and an oldest population with [O/H]=-2.0. The values are based on spectra of two planetary nebulae (PNe), using empirical abundance determinations. We calculated abundances for O, N, Ne, Ar, S, Cl, Fe, C and He. We confirm the high abundances of PN StWr2-21 with 12+log(O/H) = 8.57+/-0.02 dex. The other PN studied, BoBn1, is an extraordinary object in that the neon abundance exceeds that of oxygen. The abundances of S, Ar and Cl in BoBn1 yield the original stellar metallicity, corresponding to 12+log(O/H) = 6.72+/-0.16 dex which is 1/110 of the solar value. The actual [O/H] is much higher: third dredge-up enriched the material by a factor of ~12 in oxygen, ~240 in nitrogen and ~70 in neon. Neon as well as nitrogen and oxygen content may have been produced in the intershell of low-mass AGB stars. Well defined broad WR lines are present in the spectrum of StWr2-21 and absent in the spectrum of BoBn1. This puts the fraction of [WR]-type central PNe stars to 67% for dSph galaxies.

Affiliated with

Also associated with

No associations

Rating

The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe 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 The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The metallicity extremes of the Sagittarius dSph using SALT spectroscopy of PNe will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-230169