Análisis fotométrico-espectroscópico de estrellas candidatas a blue stragglers en los cúmulos abiertos IC4651 y NGC6281

JOFRÉ, E.; PETRUCCI, R.; GONZALEZ, J. F.; MUÑOZ, M. R.

Malargüe, Mendoza, Argentina

Congreso; 50 Reunión de la Asociación Argentina de Astronomía; 2007

Asociación Argentina de Astronomía

<!-- @page { size: 8.5in 11in; margin: 0.79in } P { margin-bottom: 0.08in } --> We report spectroscopic and photometric measurements of stars 6 and 44 belonging to the open clusters NGC6281 and IC4651 respectively, both of binary nature, blue stragglers candidates. The spectra were measured for radial velocities by the cross-correlation technique, using echelle spectra that has been obtained with the 2,15m telescope of the CASLEO. The preliminary physical parameters for both systems were fitted using the Wilson-Devinney code. The star IC4651-44 is a simple line spectroscopy binary that present sinusiodals variations of velocity with a period P=1.12 days and photometric variations of centesimal of magnitude. These light variations are produced by the deformation of the primary star owing the tidal forces. The preliminary results would indicate that the system present an orbit with a semimajor axis of 5.89Rsol and with an inclination of roughly 30 degrees, while the primary component has a radius of roughly 2.23Rsol and a mass of 2.3Msol. On the other hand, the star NGC6281-6, with double-lined spectra, present photometric variations of roughly 5 centesimal of magnitude, with a period of P=8.04 days. Due to the characteristics of his light curve, this could be an eclipsing binary, but we need more photometric data to confirm these results. The physical parameters derived for the primary star are R1=3.87 Rsol , M1=2.76 Msol. These parameters belong to an orbit with a semimajor axis of 21.54Rsol and with an inclination of 89.2 degrees.