Skip to content
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Menu
Home
About Us
Resources
Profiles Metrics
Authors Directory
Institutions Directory
Top Authors
Top Institutions
Top Sponsors
AI Digest
Contact Us
Publication Details
AFRICAN RESEARCH NEXUS
SHINING A SPOTLIGHT ON AFRICAN RESEARCH
earth and planetary sciences
The metallicity extremes of the Sagittarius dSph: SALT spectroscopy of PNe
Monthly Notices of the Royal Astronomical Society, Volume 388, No. 4, Year 2008
Notification
URL copied to clipboard!
Description
In this work we present the first spectroscopic results obtained with the Southern African Large Telescope (SALT) during its performance-verification phase. We find that the Sagittarius dwarf spheroidal galaxy (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 StWr 2-21 with 12 + log(O/H) = 8.57 ± 0.02 dex. The other PN studied, BoBn 1, is an extraordinary object in that the neon abundance exceeds that of oxygen. The abundances of S, Ar and Cl in BoBn 1 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 asymptotic giant branch (AGB) stars. Well defined broad WR lines are present in the spectrum of StWr 2-21 and absent in the spectrum of BoBn 1. This puts the fraction of [WR]-type central PNe stars to 67 per cent for dSph galaxies. © 2008 The Authors.
Authors & Co-Authors
Kniazev, Alexei Yu
South Africa, Cape Town
South African Astronomical Observatory
Russian Federation, Nizhny Arkhyz
Special Astrophysical Observatory, Russian Academy of Sciences
Albert A. Zijlstra, Albert A.
South Africa, Cape Town
South African Astronomical Observatory
United Kingdom, Manchester
The University of Manchester
Grebel, Eva K.
Germany, Heidelberg
Astronomisches Rechen-institut
Pilyugin, Leonid S.
Ukraine, Kyiv
Main Astronomical Observatory Nasu
Pustilnik, Simon A.
Russian Federation, Nizhny Arkhyz
Special Astrophysical Observatory, Russian Academy of Sciences
Väisänen, Petri S.M.
South Africa, Cape Town
South African Astronomical Observatory
Buckley, David A.H.
South Africa, Cape Town
South African Astronomical Observatory
Hashimoto, Yasuhiro
South Africa, Cape Town
South African Astronomical Observatory
Loaring, Nicola S.
South Africa, Cape Town
South African Astronomical Observatory
Romero-Colmenero, Encarnacion
South Africa, Cape Town
South African Astronomical Observatory
Still, Martin D.
South Africa, Cape Town
South African Astronomical Observatory
Burgh, Eric B.
United States, Madison
University of Wisconsin-madison
Nordsieck, Kenneth H.
United States, Madison
University of Wisconsin-madison
Statistics
Citations: 68
Authors: 13
Affiliations: 6
Identifiers
Doi:
10.1111/j.1365-2966.2008.13435.x
ISSN:
00358711
e-ISSN:
13652966
Study Design
Cross Sectional Study