Ultraviolet photometry from the orbiting astronomical observatory. VIII. The blue AP stars.
1973; IOP Publishing; Volume: 185; Linguagem: Inglês
10.1086/152440
ISSN1538-4357
Autores Tópico(s)Stellar, planetary, and galactic studies
Resumoview Abstract Citations (81) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ultraviolet photometry from the Orbiting Astronomical Observatory. VIII. The blue Ap stars. Leckrone, D. S. Abstract The Wisconsin Experiment Package filter photometers on OAO-2 were used to obtain data for a carefully selected set of 24 blue (B - V < 0.00) Ap stars and 31 comparison standard B and A dwarfs and giants for a program of relative photometry over the effective wavelength range 1430-4250 A. The Ap stars observed include members of the Si, Hg-Mn, and Sr-Cr-Eu peculiarity classes, and most of them are too blue in B - V for their published MK spectral classes. The close similarity, deduced from ground-based observations, between the blue Ap stars and normal B stars of similar UB V colors is not maintained in the ultraviolet. The blue Ap stars emit less ultraviolet flux than normal stars of like UB V colors. They are underluminous and cool in effective temperature for their colors. The Hg-Mn stars are less flux-deficient in the ultraviolet, for their UBVcolors, than are Si and Sr-Cr-Eu stars. In most cases the ultraviolet flux distribution of a blue Ap star closely resembles that of a normal star of similar MK spectral class. These results are confirmed by ultraviolet spectrophotometry at 10 and 20 A resolution of the Si star 0 Aur, data also obtained with OAO-2. Interesting differences in detail between 0 Aur and normal stars are evident in the latter data. The possible role of enhanced ultraviolet opacities in modifying the shape of the emergent flux envelope of an Ap star and in modifying its atmospheric structure, relative to normal B stars, is discussed. Subject headings: peculiar A stars - spectrophotometry - ultraviolet Publication: The Astrophysical Journal Pub Date: October 1973 DOI: 10.1086/152440 Bibcode: 1973ApJ...185..577L full text sources ADS | data products SIMBAD (57) Related Materials (37) Part 1: 1970ApJ...161..377C Part 2: 1972ApJ...171..293B Part 3: 1972ApJ...172..755W Part 4: 1972ApJ...178..727D Part 5: 1972ApJ...178..189B Part 6: 1972ApJ...178..495D Part 7: 1973ApJ...179..527M Part 9: 1973ApJ...185..921E Part 10: 1974ApJ...189..303G Part 11: 1974ApJ...187..521D Part 12: 1973ApJ...186..939H Part 13: 1974ApJ...187..197S Part 14: 1974ApJ...187..243J Part 15: 1974ApJ...190..319L Part 16: 1974ApJ...191..659S Part 17: 1975ApJ...195..121D Part 18: 1975ApJ...197..379E Part 19: 1975ApJ...199...92S Part 20: 1976ApJ...203..410B Part 21: 1976Ap&SS..41..121K Part 22: 1976ApJ...206..167P Part 23: 1976ApJ...208..135L Part 24: 1976ApJ...208...64L Part 25: 1979ApJ...228...95C Part 26: 1977ApJ...211..207H Part 27: 1978ApJ...219..947L Part 28: 1978ApJ...222..909W Part 29: 1978ApJ...220..582E Part 30: 1979ApJS...39..195C Part 31: 1979ApJ...229..994G Part 32: 1980ApJS...43..501C Part 33: 1979ApJ...228..419W Part 34: 1980ApJ...236..798W Part 35: 1980ApJS...42..283M Part 36: 1984ApJ...281..774C Part 37: 1982ApJ...256....1C Part 38: 1982AJ.....87..849D
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