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J/A+A/335/973       84 UMa ubvy photometry (Wade+ 1998)

Magnetic field models for A and B stars. V. The magnetic field and photometric variations of 84 UMa Wade G.A., Hill G.M., Adelman S.J., Manset N., Bastien P. <Astron. Astrophys. 335, 973 (1998)> =1998A&A...335..973W (SIMBAD/NED BibCode)
ADC_Keywords: Stars, peculiar ; Stars, Be ; Stars, Bp ; Photometry, uvby Keywords: stars: chemically peculiar - stars: individual: 84 UMa - Stars: magnetic fields - polarisation Abstract: We present new longitudinal magnetic field and Stroemgren photometric measurements of the Bp star 84 UMa. From these data we determine a new rotational period Prot=1.38576±0.00080d, which is inconsistent with previously published values. The magnetic measurements indicate the presence of a weak, dominantly dipolar magnetic field in the photosphere of 84 UMa. We employ a new value of the rotational axis inclination in conjunction with the magnetic data in order to constrain the magnetic field geometry. We derive the following dipole oblique rotator parameters: i=59+17-9°, β=48+17-29°, and Bd=1620+1270-30G. A precise value of the radius (which we calculate in conjunction with the inclination using the Hipparcos parallax) allows us to locate 84 UMa on the radius-effective temperature plane. Using theoretical evolutionary tracks (Schaller et al., 1992, Cat. J/A+AS/96/269), we obtain values for the mass, age and surface gravity. These results place 84 UMa quite close to the ZAMS, a result inconsistent with the suggestion by Hubrig & Mathys (1994AN....315..343H) that the magnetic Ap stars may be near the end of their main sequence life. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 13 46 35.7 +54 25 58 84 UMa = HD 120198 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 68 73 Photometry of 84 UMa
See also: J/A+A/314/491 : HD 59435 radial velocity + Geneva photometry (Wade+ 1996) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 12 F12.4 d HJD Heliocentric Julian Date 14- 19 F6.3 mag u(v-c) variable-comparison (v-c) u magnitude 21- 26 F6.3 mag u(ch-c) check-comparison (ch-c) u magnitude 28- 33 F6.3 mag v(v-c) variable-comparison (v-c) v magnitude 35- 40 F6.3 mag v(ch-c) check-comparison (ch-c) v magnitude 42- 47 F6.3 mag b(v-c) variable-comparison (v-c) b magnitude 49- 54 F6.3 mag b(ch-c) check-comparison (ch-c) b magnitude 56- 61 F6.3 mag y(v-c) variable-comparison (v-c) y magnitude 63- 68 F6.3 mag y(ch-c) check-comparison (ch-c) y magnitude
Average and standard deviation: -------------------------------------------------------------------------- u v b y v-c ch-c v-c ch-c v-c ch-c v-c ch-c -------------------------------------------------------------------------- average -0.158 -0.391 -0.020 -0.380 -0.044 -0.340 0.002 -0.329 std. dev. 0.011 0.007 0.007 0.005 0.008 0.005 0.005 0.005 Acknowledgements: Saul J. Adelman References: Wade et al., HD 115708 1996A&A...307..500W Wade et al., HD 192678 1996A&A...313..209W Wade et al., HD 184927 1997A&A...320..172W Wade et al., HD 200311 1997MNRAS.292..748W
(End) Patricia Bauer [CDS] 22-Apr-1998
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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