J/A+A/430/1049 RR Gem BV(RI)c differential photometry (Jurcsik+, 2005)
The Blazhko behaviour of RR Geminorum. I. CCD photometric results in 2004.
Jurcsik J., Sodor A., Varadi M., Szeidl B., Washuettl A , Weber M.,
Dekany I., Hurta Zs., Lakatos B., Posztobanyi K., Szing A., Vida K.
<Astron. Astrophys. 430, 1049 (2005)>
=2005A&A...430.1049J 2005A&A...430.1049J
ADC_Keywords: Stars, variable ; Photometry, CCD ; Photometry, UBVRI ;
Photometry, Cousins
Keywords: stars: individual: RR Gem - stars: variables: RR Lyr -
stars: oscillations - stars: horizontal-branch -
techniques: photometric
Abstract:
Extended CCD monitoring of RR Gem revealed that it is a Blazhko type
RRab star with the shortest Blazhko period (7.23d) and smallest
modulation amplitude (deltaMmax<0.1mag) currently known. The
short period of the modulation cycle enabled us to obtain complete
phase coverage of the pulsation at each phase of the modulation. This
is the first multicolour observation of a Blazhko star which is
extended enough to define accurate mean magnitudes and colours of the
variable at different Blazhko phases. Small, but real, changes in the
intensity mean colours at different Blazhko phases have been
detected. The Fourier analysis of the light curves shows that, in
spite of the mmag and smaller order of the amplitudes, the triplet
structure is noticeable up to about the 14th harmonic. The modulation
is concentrated to a very narrow, 0.2 phase range of the pulsation,
centred on the supposed onset of the H emission during rising light.
These observational results raise further complications for
theoretical explanation of the long known but poorly understood
Blazhko phenomenon.
Description:
The observations were obtained with the automated 60cm telescope of
Konkoly Observatory, Svabhegy, Budapest equiped with a Wright 750x1100
CCD using BV(RI)c filters, between 14 January and 4 May 2004.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------
07 07 21.3 +22 42 13 R Gem = HD 53791
07 21 40.4 +30 52 24 BD+31 1549 = HD 57247
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 24 3065 Relative B magnitudes respect to BD+31 1549
table2.dat 24 3141 Relative V magnitudes respect to BD+31 1549
table3.dat 24 3044 Relative Cousins R magnitudes respect to BD+31 1549
table4.dat 24 3000 Relative Cousins I magnitudes respect to BD+31 1549
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat table2.dat table3.dat table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.4 d HJD Heliocentric Julian Date
15 A1 --- Band [BVRI] Photometric Cousins band
19- 24 F6.4 mag Dmag Differential magnitude in "Band" band
--------------------------------------------------------------------------------
Acknowledgements: A. Sodor, sodor(at)konkoly.hu
(End) Patricia Vannier [CDS] 14-Oct-2004