2000A&A...361.1121M

Query : 2000A&A...361.1121M

2000A&A...361.1121M - Astronomy and Astrophysics, volume 3611121-1126 (2000/9-3)

On the abundance gradient of the galactic disk.

MARTINS L.P. and VIEGAS S.M.

Abstract (from CDS):

Estimates of the gas temperature in planetary nebulae obtained from the [O III] emission line ratio and from the Balmer discontinuity indicate differences reaching up to 6000K (Liu & Danziger, 1993MNRAS.263..256L). The [O III] temperature is commonly used to obtain the ionic fractions of highly ionized ions, particularly the O++ and Ne++ ions when using the empirical method to calculate the elemental abundances of photoionized gas from the observed emission line intensities. However, if the gas temperature is overestimated the elemental abundances may be underestimated. In particular this may lead to an incorrect elemental abundance gradient for the Galaxy, usually used as a constraint for the chemical evolution models. Using Monte Carlo simulations, we calculate the systematic error introduced in the abundance gradient obtained from planetary nebulae by an overestimation of the gas temperature. The results indicate that the abundance gradient in the Galaxy should be steeper than previously assumed.

Abstract Copyright: ∼

Journal keyword(s): ISM: abundances - ISM: planetary nebulae: general - Galaxy: abundances

Simbad objects: 43

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Number of rows : 43
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 PN Hu 1-1 PN 00 28 15.435 +55 57 54.48           ~ 169 1
2 PN M 1-4 PN 03 41 43.4191369752 +52 17 00.267451836   15.86 14.27 15.26   ~ 126 1
3 IC 2003 PN 03 56 21.9884187048 +33 52 30.759977028   13.11 11.87 13.44   [WC3?] 261 0
4 Jonckheere 320 PN 05 05 34.2777790632 +10 42 22.924778148           O3V(f) 289 0
5 IC 418 PN 05 27 28.2059533560 -12 41 50.282287764   9.405 9.010 10.118   O7fp 1059 2
6 PN M 1-5 PN 05 46 50.0119955400 +24 22 02.848049436           ~ 123 1
7 IC 2149 PN 05 56 23.9011721904 +46 06 17.204826816   11.21 11.35     O7.5 439 0
8 IC 2165 PN 06 21 42.7847803566 -12 59 14.040997076   12.146 10.782 12.305   ~ 385 0
9 PN VV 28 PN 06 25 57.2710426104 +17 47 27.136548168     12.5     [WC] 298 0
10 NGC 2371 PN 07 25 34.6883929008 +29 29 26.430252072   14.48 13.5     Oe 384 0
11 NGC 2392 PN 07 29 10.7671398096 +20 54 42.474888072     9.68     O6f 740 2
12 NGC 2867 PN 09 21 25.3832468160 -58 18 40.626683604   12.0 10.30     [WO2] 313 0
13 IC 2501 PN 09 38 47.1901701864 -60 05 30.807638520   11.7 10     O3-6 188 1
14 WRAY 16-59 PN 09 47 24.7963333896 -48 58 14.652965964     13.50     ~ 70 0
15 WRAY 17-45 PN 10 31 31.95 -53 33 29.5     15.00     ~ 45 0
16 IC 2621 PN 11 00 20.028432 -65 14 57.82920   12.923 11.424 13.309   wels 136 0
17 NGC 3918 PN 11 50 17.7709504944 -57 10 57.017302428   10.0 8.5     ~ 390 1
18 PN Th 2-A PN 13 22 33.9621965258 -63 21 02.014697519           [WO3]pec 99 1
19 WRAY 16-162 PN 15 05 16.80 -55 11 10.5     14.50     ~ 119 0
20 NGC 5882 PN 15 16 49.9562553264 -45 38 58.616280132   11.9 10.9     ~ 281 1
21 WRAY 16-195 PN 15 59 08.85 -58 23 52.8     14.00     ~ 98 0
22 NGC 6210 PN 16 44 29.5191019368 +23 47 59.421958296   12.3 11.7     Of/[WR] 597 0
23 NGC 6309 PN 17 14 04.3074600360 -12 54 37.893271860   11.6       O(He) 320 1
24 NGC 6439 PN 17 48 19.820 -16 28 44.42     12.2     ~ 180 0
25 NGC 6543 PN 17 58 33.4039587288 +66 37 58.750734000   11.09 11.28     [WC] 1197 2
26 NGC 6565 PN 18 11 52.4858232888 -28 10 42.421241244   12.5 12.2 12.12   PN 233 0
27 NGC 6563 PN 18 12 02.50 -33 52 07.0   11.7 10     ~ 185 1
28 NGC 6572 PN 18 12 06.3181909152 +06 51 13.027935240   9.3 10.8     [WC] 761 0
29 NGC 6578 PN 18 16 16.5071627654 -20 27 02.743192002           [WC4/6] 211 0
30 PN M 1-54 PN 18 36 08.357 -16 59 57.02           ~ 87 0
31 IC 4776 PN 18 45 50.705 -33 20 34.12   11.98 10.62     [WC]pec 204 1
32 M 57 PN 18 53 35.0967659112 +33 01 44.883287544   15.405 15.769 15.901 16.062 DA(O?) 868 2
33 IC 1297 PN 19 17 23.4475188000 -39 36 46.253665872     10.89     [WC3/4] 170 0
34 NGC 6790 PN 19 22 56.972976 +01 30 46.40112   12.247 10.504 12.684   wels 329 0
35 NGC 6818 PN 19 43 57.770472 -14 09 13.36932     9.3     ~ 357 1
36 NGC 6826 PN 19 44 48.1500225888 +50 31 30.249034932   9.779 9.359 10.775   O3f(H) 736 0
37 NGC 6884 PN 20 10 23.6424784416 +46 27 39.631794408   11.9 10.9     ~ 322 1
38 NGC 6879 PN 20 10 26.6930056361 +16 55 21.272110541   13.661 12.540 14.075   O3f(He) 157 0
39 NGC 6886 PN 20 12 42.83016 +19 59 22.6320   13.053 11.719     ~ 325 1
40 NGC 6894 PN 20 16 23.965 +30 33 53.17           ~ 206 0
41 NGC 7026 PN 21 06 18.5723414928 +47 51 06.774735780   15.33 15.1     [WC3] 427 1
42 IC 5217 PN 22 23 55.7180137224 +50 58 00.464340252     15.5     [WC7] 314 0
43 NGC 7662 PN 23 25 53.8318792825 +42 32 05.835828380       11.427   ~ 940 1

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