J/MNRAS/431/2106 CU Vir Stroemgren differential photometry (Pyper+, 2013)
An update on the rotational period of the magnetic chemically peculiar star
CU Virginis.
Pyper D.M., Stevens I.R., Adelman S.J.
<Mon. Not. R. Astron. Soc., 431, 2106-2110 (2013)>
=2013MNRAS.431.2106P 2013MNRAS.431.2106P
ADC_Keywords: Stars, variable ; Stars, peculiar ; Photometry, uvby
Keywords: stars: chemically peculiar - stars: individual: CU Vir -
stars: individual: HD 124224 - stars: individual: HR 5313-
radio continuum: stars
Abstract:
In order to measure the variations of the magnetic chemically peculiar
star CU Vir, we obtained 2821 good Stroemgren uvby photometric values
from the Four College Automated Photometric Telescope in the period
1998-2012 and 5529 values from the Solar Mass Ejection Imager in the
period 2003-2006, allowing us to further clarify the situation
concerning its rotational period, described previously by Pyper et al.
(1998A&A...339..822P 1998A&A...339..822P). Our main result is that the O-C data since 1993
are consistent with a constant period of 0.5207137±0.0000010d, which
is longer than the period 0.52070308d of Pyper et al.
(1998A&A...339..822P 1998A&A...339..822P). The data during the time period 1993-2012 show
no evidence of glitches. The data between 1987 and 1993 correspond to
a shorter period of 0.520701d, and the inclusion of those data in the
previous study made the published period come out shorter. We also
cannot rule out a constantly lengthening period if the data since 1987
are included; however, the fit is slightly better for a constant
period. At least five more years of consistent data will be required
to distinguish between these two models. Radio astronomy data
published since 1998 show phase shifts in the radio emission peaks
that are inconsistent with the rotation period inferred from the
optical photometry. These shifts may be due to instabilities in the
region where the radio emissions originate; they indicate that the
photosphere and the upper atmosphere are not rigidly coupled.
Description:
Our data are from two sources: Stroemgren differential uvby photometry
obtained using the Four College Automated Photometric Telescope
(FCAPT) originally on Mt. Hopkins, AZ, and later at Fairborn
Observatory, Washington Camp, AZ, and photometry from the Solar Mass
Ejection Imager (SMEI).
Objects:
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RA (2000) DE Designation(s)
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14 12 15.81 +02 24 34.0 CU Vir = HR 5313
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 2820 Stroemgren photometry of CU Virginis
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Season Season (i.e. 1990-1991)
9- 20 F12.4 d HJD Heliocentric Julian Date of observation
22- 27 F6.3 mag Dumag Differential Stroemgren u magnitude (1)
29- 33 F5.3 mag Dvmag Differential Stroemgren v magnitude (1)
35- 39 F5.3 mag Dbmag Differential Stroemgren b magnitude (1)
41- 45 F5.3 mag Dymag Differential Stroemgren y magnitude (1)
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Note (1): The values are: variable star - comparison star
(Comparison star = HD 122408).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 16-Jun-2014