J/A+AS/133/7 V photometry of YY CMi (Niarchos+ 1998)
YY CMi: contact or near contact system?
Niarchos P.G, Mantegazza L., Poretti E., Manimanis V.
<Astron. Astrophys. Suppl. Ser. 133, 7 (1998)>
=1998A&AS..133....7N 1998A&AS..133....7N (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Photometry
Keywords: stars: individual: YY CMi - binaries: eclipsing - starspots
Abstract:
New V photoelectric observations of the eclipsing system YY CMi,
obtained at La Silla, Chile, and Merate Observatory, Italy, are
presented. New times of minima and ephemeris based on our observations
are also given. The V light curve was analysed by using the WD code to
derive the geometrical and physical parameters of the system. Since no
spectroscopic mass ratio is available, the q-search method was applied
to yield the preliminary range of the mass ratio in order to search
for the final solution. First the unspotted solution was carried out
by using the unperturbed parts of the light curve and applying the DC
program of the WD code. The solution was performed by assuming contact
(mode 3) and semi-detached (mode 4) configuration, since no
classification of the system is possible from the shape of the light
curve. The solution in mode 4 does not lead to an acceptable model,
since the secondary was found to be slightly overcontact. Therefore
the contact solution was finally adopted. Moreover the light curve
peculiarities (MaxII fainter than MaxI and excess of light around the
phase 0.32) were explained by assuming a cool and a hot spot on the
surface of the secondary (cooler) component. The degree of contact is
very small (f≃3%) and the thermal contact is poor (T1-T2)≃650K.
These results together with the high photometric mass ratio q≃0.89
indicate that YY CMi is very probably a system at the beginning or the
end of the contact phase.
Objects:
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RA (2000) DE Designation(s)
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08 06 38.5 +01 55 46 YY CMi = HD 67110
08 05 47.7 +02 09 54 HD 66925
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 19 429 Individual V observations of YY CMi
table1.tex 77 172 LaTeX version of table.dat
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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- 12 F12.4 d HJD Heliocentric Julian date
14- 18 F5.3 mag {DELTA}V V magnitude difference respect with HD 66925
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Acknowledgements: Ennio Poretti
(End) Patricia Bauer [CDS] 15-May-1998