2020MNRAS.496.2726M

Query : 2020MNRAS.496.2726M

2020MNRAS.496.2726M - Mon. Not. R. Astron. Soc., 496, 2726-2742 (2020/August-2)

Helium abundances and its radial gradient from the spectra of H II regions and ring nebulae of the Milky Way.

MENDEZ-DELGADO J.E., ESTEBAN C., GARCIA-ROJAS J., ARELLANO-CORDOVA K.Z. and VALERDI M.

Abstract (from CDS):

We determine the radial abundance gradient of helium in the disc of the Galaxy from published spectra of 19 H II regions and ring nebulae surrounding massive O-type stars. We revise the Galactocentric distances of the objects considering Gaia DR2 parallaxes (Gaia Collaboration 2018) and determine the physical conditions and the ionic abundance of He+ in a homogeneous way, using between 3 and 10 He I recombination lines in each object. We estimate the total He abundance of the nebulae and its radial abundance gradient using four different ionization correction factor (ICF; He) schemes. The slope of the gradient is always negative and weakly dependent on the ICF(He) scheme, especially when only the objects with log(η) < 0.9 are considered. The slope values go from -0.0078 to -0.0044 dex kpc–1, consistent with the predictions of chemical evolution models of the Milky Way and chemodynamical simulations of disc galaxies. Finally, we estimate the abundance deviations of He, O, and N in a sample of ring nebulae around Galactic Wolf-Rayet stars, finding a quite similar He overabundance of about +0.24 ± 0.11 dex in three stellar ejecta ring nebulae.

Abstract Copyright: © 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): ISM: abundances - ISM: bubbles - HII regions - Galaxy: abundances - Galaxy: disc - Galaxy: evolution

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 36

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Number of rows : 36
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 NGC 300 GiG 00 54 53.4465638304 -37 41 03.168402396 8.83 8.69 8.13 7.46   ~ 1614 2
2 SH 2-209 HII 04 11 06.7 +51 09 44           ~ 105 0
3 SH 2-212 HII 04 40 36.52 +50 27 44.3           ~ 102 2
4 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
5 M 42 HII 05 35 16.8 -05 23 15           ~ 4411 0
6 NAME 30 Dor Nebula SFR 05 38 36.0 -69 05 11           ~ 1276 2
7 HD 50896 WR* 06 54 13.0439608392 -23 55 42.023319852 5.74 6.63 6.91 7.74   WN4b 794 0
8 IC 466 HII 07 08 37 -04 18.8           ~ 49 0
9 RAFGL 5223 Or* 07 08 38.7906809616 -04 19 04.847636136 12.48 12.71 12.06     B0 46 0
10 NGC 2359 HII 07 18 30.000 -13 13 36.00           ~ 170 0
11 NGC 2467 OpC 07 52 18 -26 25.7           ~ 190 1
12 HD 64315 EB* 07 52 20.2841727949 -26 25 46.683038109 8.76 9.49 9.24 9.63 8.86 O5.5Vz+O7V 124 1
13 NGC 2579 OpC 08 20 55.3 -36 13 23           ~ 110 4
14 NGC 3372 HII 10 45 02.23 -59 41 59.8           ~ 1071 2
15 GUM 32 HII 10 46 11.5 -58 39 12           ~ 16 1
16 HD 96548 WR* 11 06 17.2032351624 -65 30 35.241182028 7.10 7.80 7.70 8.49   WN8h 427 0
17 NGC 3576 HII 11 11 53.2 -61 18 26           ~ 245 2
18 NGC 3603 OpC 11 14 57.9 -61 14 32           ~ 1136 1
19 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
20 SNR G002.4+01.4 HII 17 45 50.0 -26 14 28           ~ 58 2
21 PN M 2-24 PN 18 02 02.8945854456 -34 27 47.275175592   15.62 14.60 15.29   ~ 100 0
22 M 20 OpC 18 02 42 -22 58.3           ~ 456 1
23 M 8 OpC 18 03 37 -24 23.2           ~ 644 1
24 M 16 OpC 18 18 45.1 -13 47 31           ~ 1084 1
25 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1700 0
26 Hen 2-427 WR* 19 11 30.8749167768 +16 51 38.200938264   12.19 11.50     WN8h 350 0
27 SH 2-83 HII 19 24 30.01 +20 47 34.5           ~ 45 1
28 LBN 070.24+01.53 HII 20 01 44.7 +33 31 14           ~ 40 1
29 HD 192163 WR* 20 12 06.5418877464 +38 21 17.784181008 7.12 7.49 7.50     WN6(h)-s 715 1
30 LBN 096.23+02.55 HII 21 28 42 +54 37.0           ~ 54 0
31 SH 2-128 HII 21 32 09.9 +55 52 53           ~ 173 1
32 ALS 19702 * 21 32 10.3215352416 +55 52 42.511229076 16.94 16.37 14.96 14.82   O7 8 0
33 LBN 108.78-01.01 HII 22 58 37 +58 46.8           ~ 57 0
34 SH 2-152 HII 22 58 40.8107767416 +58 46 59.226036024           ~ 147 1
35 NGC 7535 LSB 23 14 12.6178677552 +13 34 54.549232680 14.22 14.24 13.66     ~ 41 1
36 NGC 7635 HII 23 20 48.3 +61 12 06           ~ 179 2

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