1996A&A...305..902S


Query : 1996A&A...305..902S

1996A&A...305..902S - Astronomy and Astrophysics, volume 305, 902-910 (1996/1-3)

Elemental abundances in normal late-B and HgMn stars from co-added IUE spectra. IV. Gallium.

SMITH K.C.

Abstract (from CDS):

An analysis is presented of the ultraviolet gallium resonance lines in International Ultraviolet Explorer (IUE) spectra of 40 normal, superficially normal, and HgMn-type late-B stars. Gallium abundances are derived by fitting the GaIIλ1414, and GaIIIλλ1495, 1534 lines with synthetic spectra computed under the conventional assumptions of local thermodynamic equilibrium (LTE) and atmospheric chemical homogeneity. We find that the derived upper limits on the gallium abundances of the normal and superficially normal stars are consistent with the solar value. However, gallium is overabundant in essentially all HgMn stars, including the cooler examples such as HR 4072, χ Lup, and ι CrB, where the enhancements are relatively moderate and unambiguous identification of the resonance lines depends critically on newly available laboratory wavelengths. Furthermore, the gallium overabundances in the HgMn stars exhibit a loose correlation with effective temperature, similar in most respects to those identified for manganese and copper in the same stars except for the presence of the anomalously Ga-rich, cool HgMn star HR 7775. We show that a systematic discrepancy between the abundances derived from the Ga+ and Ga2+ ions in the hotter HgMn stars (Teff>12000K) can be explained by radiative transfer effects in the presence of a stratification of gallium at optical depths above logτ0≃0. This `stratification model' can also account for the anomalously shaped GaIII λ1495 profiles observed in the extreme cases of µ Lep, HR 2844, and HR 7143 (as demonstrated in a previous paper), and is consistent with published predictions of radiative diffusion theory for non-magnetic stars.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: atmospheres - stars: chemically peculiar - stars: early-type - ultraviolet: stars

Simbad objects: 38

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Number of rows : 38
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 * 87 Psc SB* 01 14 07.6281618312 +16 08 00.514454568   5.873 5.962     B8III 137 0
2 * phi Phe SB* 01 54 22.0319152104 -42 29 48.942141036   5.055 5.109     A3V 109 0
3 * pi. Cet SB* 02 44 07.3492803 -13 51 31.313011 3.66 4.112 4.236     B7IV 322 0
4 * 53 Tau a2* 04 19 26.0975894496 +21 08 32.298968148   5.413 5.482     B9Vsp 260 0
5 * mu. Lep a2* 05 12 55.9029641016 -16 12 19.668599100 2.78 3.18 3.29 3.30 3.42 B9IV:HgMn 270 1
6 HD 35548 SB* 05 25 31.0806774 -00 32 38.208969 6.34 6.52 6.57     B9III 143 1
7 * 134 Tau * 05 49 32.9297423 +12 39 04.758221 4.68 4.811 4.875     B9IV 186 0
8 * 33 Gem Ro* 06 49 49.8362378064 +16 12 10.382708016 5.24 5.72 5.87     B7III 141 0
9 HD 53929 * 07 07 06.4712319600 +04 54 38.091397320 5.52 5.961 6.088     B9III 90 0
10 HD 58661 ** 07 28 51.4870582200 +48 11 02.180139576   5.611 5.703     B9IIIpSr 100 0
11 * nu. Cnc SB* 09 02 44.2677118128 +24 27 10.392222600   5.404 5.447     A0III 193 0
12 * kap Cnc a2* 09 07 44.8095541176 +10 40 05.519586828 4.70 5.13 5.24     B8IIImnp 357 0
13 * 36 Lyn Ro* 09 13 48.2131781112 +43 13 04.193952924 4.72 5.148 5.282     ~ 205 0
14 V* ET UMa a2* 10 24 07.8468791760 +65 33 59.121373140   4.889 4.930     A1:VpSiSrHg 268 0
15 * tet Leo PM* 11 14 14.4044630 +15 25 46.454086 3.40 3.33 3.35 3.32 3.34 A2IV 325 0
16 * chi Lup SB* 15 50 57.5382881 -33 37 37.795321 3.77 3.909 3.946     B9III 299 0
17 * iot CrB SB* 16 01 26.5649192496 +29 51 03.819408336   4.921 4.971     A0IIIspHgMnEu 260 0
18 * ups Her PM* 16 02 47.8978183032 +46 02 12.133917132 4.33 4.616 4.709     B9III 232 0
19 * tau Her Pu* 16 19 44.43666 +46 18 48.1123 3.190 3.73 3.87 4.00 4.16 B5IV 394 0
20 * n Her * 16 32 35.6854246680 +05 31 16.391769564 5.39 5.57 5.63     B9.5III 114 0
21 * zet Dra ** 17 08 47.1959624 +65 42 52.863384 2.63 3.06 3.17 3.23 3.35 B6III 216 0
22 HD 172044 SB* 18 36 37.3442332272 +33 28 08.537976300 4.8 5.301 5.410     B8IIpHgMn 147 0
23 * alf Lyr dS* 18 36 56.33635 +38 47 01.2802 0.03 0.03 0.03 0.07 0.10 A0Va 2600 0
24 HD 174567 * 18 49 44.0870486208 +31 37 46.054879392   6.615 6.632     A0Vs 56 0
25 * 112 Her SB* 18 52 16.4279808528 +21 25 30.512193132 4.83 5.304 5.393     B9pHg 196 0
26 HD 175640 * 18 56 22.6598858520 -01 47 59.503936200 5.86 6.149 6.196     B9IIIpHgMnEu 143 0
27 * 21 Aql a2* 19 13 42.7011956712 +02 17 37.310297604 4.67 5.08 5.15     B7III 230 0
28 HD 181470 SB* 19 19 01.1490176496 +37 26 43.241751420 6.190 6.260 6.260     A0III 77 0
29 HD 182308 * 19 19 46.1395312128 +64 23 26.907669564   6.413 6.504     A0Ib 96 0
30 * 46 Aql * 19 42 12.8123363760 +12 11 35.740659732   6.234 6.321     B9III 111 0
31 * 14 Sge SB* 20 03 30.0147595968 +16 01 52.508306604 5.39 5.550 5.658     B9pHgMn 131 0
32 * kap Cep * 20 08 53.3487448872 +77 42 41.115549672   4.35 4.40     B9III 134 0
33 * nu. Cap * 20 20 39.8156206 -12 45 32.684421 4.61 4.72 4.76 4.75 4.81 B9IV 265 0
34 * bet02 Cap ** 20 20 46.5478935096 -14 47 05.603724348   6.08 6.10     B9/A0III/IV 137 0
35 HD 196426 * 20 37 18.3814212168 +00 05 49.053778404 5.73 6.112 6.211     B8IIIpec 82 0
36 * 21 Peg * 22 03 19.0326115488 +11 23 11.574375540   5.762 5.822     B9.5V 140 0
37 * ksi Oct Pu* 22 50 22.8139009656 -80 07 25.841844408 4.7 5.180 5.311     B6V 89 0
38 * bet Scl PM* 23 32 58.2589788 -37 49 05.757000 3.92 4.28 4.37 4.37 4.44 B9.5IIIpHgMnSi 173 0

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2022.08.09-22:29:12

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