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J/A+A/324/949       Properties of He-rich stars I.     (Zboril+ 1997)

Properties of He-rich stars I. Their evolutionary state and helium abundance Zboril M., North P., Glagolevskij Yu.V., Betrix F. <Astron. Astrophys. 324, 949 (1997)> =1997A&A...324..949Z (SIMBAD/NED BibCode)
ADC_Keywords: Stars, peculiar Keywords: stars: abundances - stars: atmospheres - stars: chemically peculiar - stars: fundamental parameters Abstract: A determination of the surface gravity and an abundance analysis of helium in a sample of 17 He-rich and 5 normal, reference stars is presented. These results are derived from low resolution CCD spectra, but each star was measured at least 6 times in order to obtain a significant average spectrum for the spectroscopic variables. The helium abundances derived from the models used are very close to 0.1 for normal, reference stars and are larger for the others, clearly indicating the He-rich phenomenon in them. NLTE effects, errors on the microturbulence value or on the surface gravity do not influence the estimated helium abundances. Nevertheless, synthesized Geneva colours are affected by the He-rich peculiarity, especially the [U-B] index which systematically changes by -0.025 mag per 0.1 of He abundance for the coolest stars in the sample. We cannot confirm the correlation between the evolutionary state and the helium abundance reported previously (Zboril et al. 1994, in "International Conference on CP and Magnetic Stars.", Tatranska Lomnica, eds. J. Zverko and J. Ziznovsky, p. 105), although we used a more reliable technique of log(g) determination. All He-rich objects lie within the main sequence: their surface gravities are all inside the range 4.1<logg<4.5, with no more than three objects having logg<4.25. We find a significant spread of helium abundances in this range of surface gravities, from the solar value ∼0.1 up to about 0.4. Some of the programme stars (including reference stars) present emission in their Balmer lines and therefore some kind of stellar activity. Strong helium overabundance often coexists with emission and stellar activity. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 05 32 00.4 -00 17 04 HD 36485 = HR 1851 05 35 21.8 -04 29 38 HD 37017 = HR 1890 05 38 47.1 -02 35 40 HD 37479 = HR 1932 05 40 56.3 -01 30 26 HD 37776 = BD-01 1005 06 37 46.6 +12 46 05 HDE 260858 = BD+12 1223 06 47 53.8 +04 40 01 HDE 264111 = HD 264111 = BD+04 1447 07 12 02.2 -27 43 05 CoD-27 3748 = SAO 173185 07 14 48.7 -26 46 22 HD 56139 = HR 2749 07 23 19.6 -36 20 25 HD 58260 = CD-36 3578 07 33 02.1 -23 56 03 HD 60344 = CD-23 5673 07 53 03.7 -49 36 47 HD 64740 = HR 3089 08 01 35.1 -50 36 21 HD 66522 = CD-50 3111 08 11 01.6 -37 17 32 HD 68450 = HR 3219 08 49 39.7 -46 50 51 CoD-46 4639 = CPD-46 3093 10 42 14.2 -64 27 59 HD 92938 = HR 4196 11 06 05.8 -59 56 59 HD 96446 = CD-59 3544 = CPD-59 3038 11 35 37.6 -63 15 54 CPD-62 2124 = LSS 2394 12 08 21.6 -50 43 20 HD 105435 = HR 4621 12 28 02.5 -50 13 49 HD 108483 = HR 4743 12 46 17.2 -68 06 28 HD 110879 = HR 4844 13 58 40.8 -44 48 11 HD 121790 = HR 5249 14 06 02.8 -41 10 45 HD 122980 = HR 5285 14 14 58.5 -46 17 19 HD 124448 = CD-45 9033 15 06 55.9 -52 01 47 HD 133518 = CD-51 8745 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 29 160 Journal of the spectroscopic observations table1.tex 79 148 LaTeX version of the table table1.ps 72 375 Postscript version of the table
Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
1- 11 A11 --- Name Star name (1) 13- 23 F11.3 d HJD Heliocentric Julian date (2) 25- 28 I4 s Texp Exposure time
Note (1): The stars HD 105435 and HD 121790 are rotational velocity standards from Slettebak et al., 1975ApJS...29..137S Note (2): The epochs are heliocentric Julian dates corresponding to the middle of the exposure.
Acknowledgements: Pierre North
(End) Patricia Bauer [CDS] 27-Feb-1997
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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