J/A+A/438/201 DG Leo uvby differential photometry (Lampens+, 2005)
A photometric study of the light variations of the triple system DG Leonis.
Lampens P., Fremat Y., Garrido R., Pena J.H., Parrao L., Van Cauteren P.,
Cuypers J., De Cat P., Uytterhoeven K., Arentoft T., Hobart M.
<Astron. Astrophys. 438, 201 (2005)>
=2005A&A...438..201L 2005A&A...438..201L
ADC_Keywords: Stars, double and multiple ; Photometry, uvby
Keywords: stars: binaries: visual - stars: binaries: spectroscopic -
stars: variables: delta Sct - stars: individual: DG Leo -
technique: photometry
Abstract:
Multi-site and multi-year differential photometry of the triple star
DG Leo reveals a complex frequency spectrum that can be modelled as
the combination of at least three δ Scuti type frequencies in
the range 11.5-13c/d (with semi-amplitudes of 2-7mmag) and a
superimposed slow variability of larger amplitude. The period of the
slow variation fits very well with half the orbital period of the
inner spectroscopic binary indicating the presence of ellipsoidal
variations caused by the tidally deformed components in a close
configuration. These findings, together with the results of a recent
spectroscopic analysis (showing that the system consists of a pair of
mild Am stars and one A-type component of normal solar composition),
infer that DG Leo is an extremely interesting asteroseismic target.
Identification of which component(s) of this multiple system is (or
are) pulsating and determination of the excited pulsation modes will
both contribute to a much better understanding of the non-trivial link
between multiplicity, chemical composition, rotation, and pulsation in
the lower part of the classical Cepheid instability strip.
Description:
The first table (dataset1) contains 1590 data points collected with
1.5m telescopes equipped with conventional photometers at the
observatories of San Pedro Martir, (OAN, Mexico) and Sierra Nevada,
(OSN, Spain) at the following epochs: February 4-17 2002, January 8-14
2003 and March 17-19 2004 (Data Set 1).
The data consist of differential magnitudes of DG Leonis minus the
main comparison star, HD 84497, collected in the Stroemgren
photometric system and representing about 110 hours of of
photoelectric data.
The 1071 additional data of the second table (dataset2) were collected
with a 0.1m telescope equipped with a CCD camera of type ST10Xme
(SBIG) at the observatory of Beersel Hills (BHO, Belgium) between
epochs 8-9 Jan and 14-15 Mar 2003.
Objects:
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RA (2000) DE Designation(s)
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09 49 50.1 +21 10 46 DG Leo = HD 85040 = HIP 48218
09 46 13.2 +20 29 21 HD 84497 = GSC 01416-00210 = HIP 47946
09 49 33.1 +20 47 39 HD 85017 = GSC 01417-00315 = HIP 48197
09 50 51.7 +20 47 58 HD 85215 = GSC 01417-00312 = HIP 48303
09 51 10.7 +20 53 18 GSC 1417-203 = TYC 1417- 203-1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
dataset1.dat 59 1590 *Stroemgren differential photometry
dataset2.dat 53 1071 V differential photometry
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Note on dataset1.dat: The data from Data Set 1 carry a relative weight = 1.
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Byte-by-byte Description of file: dataset1.dat
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Bytes Format Units Label Explanations
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2- 4 A3 --- Code Observatory code (G1)
7- 19 F13.5 d HJD Heliocentric Julian Date
22- 29 F8.5 mag Dumag Differential u magnitude, DG Leo - HD 84497
32- 39 F8.5 mag Dvmag Differential v magnitude, DG Leo - HD 84497
42- 49 F8.5 mag Dbmag Differential b magnitude, DG Leo - HD 84497
52- 59 F8.5 mag Dymag Differential y magnitude, DG Leo - HD 84497
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Byte-by-byte Description of file: dataset2.dat
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Bytes Format Units Label Explanations
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2- 4 A3 --- Code Observatory code (G1)
7- 19 F13.5 d HJD Heliocentric Julian Date
22- 29 F8.5 mag DVmag Differential V magnitude, DG Leo - HD 85017
32- 36 F5.3 mag DVmag2 ? Differential V magnitude, HD 85215 - HD 85017
40- 44 F5.3 mag DVmag3 ? Differential V magnitude, GSC 1417-203 - HD 85017
48- 53 F6.4 --- Weight Relative weight
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Global notes:
Note (G1): Observatory code as follows:
OAN = Observatory of San Pedro Martir
OSN = Observatory of Sierra Nevada
BHO = Observatory of Beersel Hills
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Acknowledgements: Patricia Lampens, patricia.lampens(at)oma.be
(End) Patricia Vannier [CDS] 25-Apr-2005