A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy

Details A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy

2000-09-05

arxiv.org/abs/astro-ph/0009054v1

Astronomy and Astrophysics

Astrophysics

To appear in Astron. Astrophys. (Latex, 17 pages, 1 postscript figure)

Scientific paper

Radio continuum observations at 1.4, 4.8 and 8.6 GHz of the two Planetary Nebulae (PNe) in the Sagittarius dwarf galaxy reveal the elongated shape of Wray 16-423 and the extreme compactness of He 2-436. He 2-436 is confirmed as subject to local dust extinction. Photoionization models for both PNe are obtained from two different codes, allowing theoretical uncertainties to be assessed. Wray 16-423, excited by a star of Teff 1.07x10^5K, is an ellipsoidal, matter-bounded nebula, except for a denser sector. He 2-436, excited by a 7x10^4K star, includes two radiation-bounded shells, with the inner one possibly corresponding to a transitory event. Both stars are on the same (H-burning) evolutionary track of initial mass (1.2+/-0.1) Msun and may be twins, with the PN ejection of Wray 16-423 having occured ~1500 years before He 2-436. The PN abundances re-inforce the common origin of the parent stars, indicating almost identical depletions with respect to solar for O, Ne, Mg, S, Cl, Ar, and K (-0.55+/-0.07 dex), large identical overabundances for He and strong overabundances for carbon, particularly in He2-436. Excess nitrogen makes Wray 16-423 nearly a Type I PN. These PNe provide a means to calibrate both metallicity and age of the Sagittarius stellar population, and they confirm that the youngest, most metal-rich population has an age of 5Gyr and a metallicity of [Fe/H]=-0.55, in agreement with the slope of the red giant branch. (Abridged abstract)

Affiliated with

Also associated with

No associations

Rating

A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy 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 A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A radio-continuum and photoionization-model study of the two planetary nebulae in the Sagittarius dwarf galaxy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-433042