Ultraviolet photometry from the orbiting astronomical observatory. XV.The strongly magnetic variable HD 215441.
1974; IOP Publishing; Volume: 190; Linguagem: Inglês
10.1086/152879
ISSN1538-4357
Autores Tópico(s)Astronomical Observations and Instrumentation
Resumoview Abstract Citations (48) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Ultraviolet photometry from the Orbiting Astronomical Observatory. XV. The strongly magnetic variable HD 215441. Leckrone, D. S. Abstract The Wisconsin Experiment Package on OAO-2 was used to obtain light curves of the strongly magnetic, variable Ap star RD 215441 over the wavelength range 155() 4250 A. This star is characterized by a lack of outstanding spectrum variability at wavelengths accessible from the ground, while undergoing UB V photometric variations of large amplitude. The vacuum ultraviolet data show that the UB V variations are driven by a time-variable redistribution of flux from the ultraviolet to the visible (variable backwarming), similar to the mechanism previously noted by Molnar in the well-known spectrum variables a2 CVn and e UMa. At 2980 A RD 215441 varies in phase with the visible; the data firmly establish 2460 A as a "null wavelength" at which the star does not vary systematically in brightness with phase; shortward of 2460 A the star reaches minimum brightness at the time of visible maximum. The effective temperature of RD 215441, crudely estimated as 14,5000 K, does not vary by more than a few hundred degrees over the star's cycle and may well be constant as a function of phase. The observations of RD 215441 demonstrate that an Ap star need not be a striking spectrum variable at blue-visible wavelengths for its photometric variations to be controlled by opacity variations in the ultraviolet. Subject headings: atmospheres, stellar magnetic stars - stars, individual - spectrum variables - ultraviolet Publication: The Astrophysical Journal Pub Date: June 1974 DOI: 10.1086/152879 Bibcode: 1974ApJ...190..319L full text sources ADS | data products SIMBAD (5) 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 8: 1973ApJ...185..577L 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 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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