Bibcode
Huélamo, N.; Vaz, L. P. R.; Torres, C. A. O.; Bergeron, P.; Melo, C. H. F.; Quast, G. R.; Barrado y Navascués, D.; Sterzik, M. F.; Chauvin, G.; Bouy, H.; Landin, N. R.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 503, Issue 3, 2009, pp.873-881
Fecha de publicación:
9
2009
Revista
Número de citas
12
Número de citas referidas
10
Descripción
Context: HIP 96515 A is a double-lined spectroscopic binary included in
the SACY catalog as a potential young star. It has a visual companion
(CCDM 19371-5134 B, HIP 96515 B) at 8.6 arcsec. If bound to the primary,
the optical and infrared colors of this wide companion are consistent
with those of a white dwarf. Aims: We attempt to characterize the
system HIP 96515 A&B by studying each of its components. Methods: We analyzed spectroscopic and photometric observations of HIP
96515 A and its visual companion, HIP 96515 B. To confirm the system as
a common proper-motion pair, we analyzed the astrometry of the
components using high-angular resolution infrared observations obtained
within a time span of two years, and archival astrometry. Results: The high-resolution optical spectrum of HIP 96515 A was used
to derive a mass ratio, M_2/M_1, close to 0.9. The optical lightcurve of
HIP 96515 A shows periodic variations with P_orbital = 2.3456 days,
revealing that HIP 96515 A is an eclipsing binary with preliminary
orbital parameters of i = 89.0° ± 0.2°, and M1
= 0.59 ± 0.03 M&sun; and M2 = 0.54 ±
0.03 M&sun;, for the primary and secondary, respectively, at
an estimated distance of 42 ± 3 pc. This is a new eclipsing
binary with component masses below 0.6 M&sun;. Multi-epoch
observations of HIP 96515 A&B show that the system is a common
proper-motion pair. The optical spectrum of HIP 96515 B is consistent
with a pure helium atmosphere (DB) white dwarf. The comparison with
evolutionary cooling sequence models provides Teff,WD = 19
126 ± 195 K, log gWD = 8.08,
MWD/M&sun; = 0.6, and a distance of ~46 pc. The
estimated WD cooling age is ~100 Myr and the total age of the object
(including the main-sequence phase) is ~400 Myr. Finally, if HIP 96515
A&B are coeval, and assuming a common age of ~400 Myr, the
comparison of the masses of the eclipsing binary members with
evolutionary tracks shows that they are underestimated by ~15% and 10%,
for the primary and secondary, respectively.
Based on observations collected at the Paranal Observatory under
programs 77.C-0483(A) and 81.C-0826(A).