ADC/CDS Standard Document for Catalog:
/journal_tables/A+A/335/973/

1. Use the ADC Data Viewer Suite to visualize the data.
2. Get the data files via anonymous FTP. (See Note.)

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 P_rot_=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_{deg},
    {beta}=48^+17^_-29_{deg}, and B_d_=1620^+1270^_-30_G. 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 <ADELMANS@adelvx.citadel.edu>

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