000002034 001__ 2034
000002034 005__ 20160701171657.0
000002034 0247_ $$2DOI$$a10.1111/j.1365-2966.2006.10338.x
000002034 037__ $$aASTROimport-191
000002034 100__ $$aZijlstra, A. A.
000002034 245__ $$aThe planetary nebula population of the Sagittarius dwarf spheroidal galaxy
000002034 260__ $$c2006
000002034 520__ $$aThe identification of two new planetary nebulae (PNe) in the Sagittarius dwarf spheroidal galaxy (Sgr) is presented. This brings the total number to four. Both new PNe were previously classified as Galactic objects. The first, StWr 2-21, belongs to the main body of Sgr, from its velocity and location. The second, the halo PN BoBn1, has a location, distance and velocity in agreement with the leading tidal tail of Sgr. We estimate that 10 per cent of the Galactic halo consists of Sgr debris. The specific frequency of PNe indicates a total luminosity of Sgr, including its tidal tails, of MV = -14.1. StWr 2-21 shows a high abundance of [O/H]= -0.23, which confirms the high-metallicity population in Sgr uncovered by Bonifacio et al. The steep metallicity-age gradient in Sgr is due to interstellar medium (ISM) removal during the Galactic plane passages, ISM reformation due to stellar mass-loss, and possibly accretion of metal-enriched gas from our Galaxy. The ISM re-formation rate of Sgr, from stellar mass-loss, is 5 × 10-4Msolaryr-1, amounting to ~106Msolar per orbital period. Hubble Space Telescope images of three of the PNe reveal well-developed bipolar morphologies, and provide clear detections of the central stars. All three stars with deep spectra show WR lines, suggesting that the progenitor mass and metallicity determines whether a PN central star develops a WR spectrum. One Sgr PN belongs to the class of IR-[WC] stars. Expansion velocities are determined for three nebulae. Comparison with hydrodynamical models indicates an initial density profile of ρ ~ r-3. This is evidence for increasing mass-loss rates on the asymptotic giant branch. Peak mass-loss rates are indicated of ~10-4Msolaryr-1. The IR-[WC] PN, He2-436, provides the sole direct detection of dust in a dwarf spheroidal galaxy, to date. 
000002034 700__ $$a Gesicki, K.
000002034 700__ $$a Walsh, J. R.
000002034 700__ $$a Péquignot, D.
000002034 700__ $$a van Hoof, P. A. M.
000002034 700__ $$a Minniti, D.
000002034 773__ $$c875-890$$i2$$pMonthly Notices of the Royal Astronomical Society$$v369$$y2006
000002034 85642 $$ahttp://esoads.eso.org/abs/2006MNRAS.369..875Z
000002034 905__ $$apublished in
000002034 980__ $$aREFERD