Using Planetary Nebulae to Analyze the Abundance Gradient in the Milky Way

2005 ◽  
Author(s):  
M. Peña
2011 ◽  
Vol 7 (S283) ◽  
pp. 438-439
Author(s):  
Jackie B. Milingo ◽  
Richard B. C. Henry ◽  
Karen B. Kwitter ◽  
Bruce Balick

AbstractWe examine the abundance gradient in the Milky Way disk via homogeneously determined data for 124 Galactic planetary nebulae (PNe). We present recent results from a detailed regression analysis of the O gradient. With O, Ne, S, Cl, and Ar available and a range of galactocentric distance (Rg) from 0.9 to 21 kpc, we present additional exploration of the disk radial gradient by statistically analyzing a series of short segments of increasing average Rg.


2017 ◽  
Vol 43 (5) ◽  
pp. 304-315 ◽  
Author(s):  
V. V. Bobylev ◽  
A. T. Bajkova

2015 ◽  
Vol 11 (S317) ◽  
pp. 344-345 ◽  
Author(s):  
Michael G. Richer ◽  
Marshall L. McCall

AbstractThe populations of bright planetary nebulae in the discs of spirals appear to differ in their spectral properties from those in ellipticals and the bulges of spirals. The bright planetary nebulae from the bulge of the Milky Way are entirely compatible with those observed in the discs of spiral galaxies. The similarity might be explained if the bulge of the Milky Way evolved secularly from the disc, in which case the bulge should be regarded as a pseudo-bulge.


2009 ◽  
Vol 5 (S265) ◽  
pp. 354-355
Author(s):  
Oscar Cavichia ◽  
Roberto D. D. Costa ◽  
Walter J. Maciel

AbstractNew abundances of planetary nebulae located towards the bulge of the Galaxy are derived based on observations made at LNA (Brazil). We present accurate abundances of the elements He, N, S, O, Ar, and Ne for 56 PNe located towards the galactic bulge. The data shows a good agreement with other results in the literature, in the sense that the distribution of the abundances is similar to those works. From the statistical analysis performed, we can suggest a bulge-disk interface at 2.2 kpc for the intermediate mass population, marking therefore the outer border of the bulge and inner border of the disk.


Author(s):  
Grażyna Stasińska ◽  
José M. Vílchez ◽  
Enrique Pérez ◽  
Rosa M. Gonzalez Delgado ◽  
Romano L.M. Corradi ◽  
...  

1983 ◽  
Vol 103 ◽  
pp. 443-460
Author(s):  
Holland C. Ford

Recent surveys for planetary nebulae have given the first identifications in Fornax, NGC 6822, M33, IC 10, Leo A, Sextans A, Pegasus, WLM, NGC 404, and M81, and extended the identifications in the SMC, the LMC, and M31. Observations of planetaries have established chemical compositions in old or intermediate age populations in 8 Local Group galaxies. The chemical compositions show that i) the helium abundance is higher in planetary nebulae than in H II regions in the same galaxy, and ii) nitrogen is overabundant relative to H II regions by factors of 4 to 100. Planetary nebulae are not a major source of helium in star-forming galaxies, and are a major source of nitrogen. The planetary in Fornax has a relatively high O abundance, and, together with Fornax's carbon stars, establishes the presence of at least 2 stellar populations. The abundance gradient derived from 3 planetaries in M31 is very shallow, and gives high abundances at ~ 20 kpc. By using planetary nebulae as standard candles, upper and lower distance limits have been set for 10 Local Group candidates, and a new distance estimated for M81.


1996 ◽  
Vol 169 ◽  
pp. 427-428
Author(s):  
Roland Buser ◽  
Jianxiang Rong

The metallicity-sensitive (U – G) colors from the new homogeneous catalog of photographic RGU data in seven high-latitude fields have been used to determine the larger-scale metallicity distributions of the Galactic population components. For the thick disk, preliminary analysis based on our best structural models provides a mean metallicity 〈[M/H]〉 = −0.6 ± 0.3dex and a marginal vertical metallicity gradient ≈ −0.1dex/kpc. The observed color distributions are further consistent with the (old) thin disk having mean abundance 〈[M/H]〉 = −0.3 ± 0.2dex and abundance gradient ∂[M/H]/∂z = −0.6dex/kpc.


1985 ◽  
Vol 87 ◽  
pp. 359-365 ◽  
Author(s):  
S.R. Pottasch ◽  
A. Mampaso ◽  
A. Manchado ◽  
J. Menzies

AbstractNew spectra of A78 and A58 at different positions in the nebulae are presented. An abundance gradient is found in A78, extending quite close to the center. Similarly the nebulous knot near the center of A58 has considerably higher heavy element abundances than the outer regions of this nebula. The ionization state is considerably lower in A58 than A78. In A78 most of the neon is in the form of Ne+3 and Ne+4, indicating that the standard ionization correction factor as used by Jacoby and Ford, is substantially in error. Finally, the very high infrared excesses found in this nebulae are discussed.


1989 ◽  
Vol 157 (1-2) ◽  
pp. 23-29 ◽  
Author(s):  
A. Manchado ◽  
S. R. Pottasch ◽  
A. Mampaso

Sign in / Sign up

Export Citation Format

Share Document