Cool Stars 14 - Submitted Abstract # 193
This version created on 05 October 2006

Spectrophotometric analysis of the classical T Tauri star GQ Lup A


Silvia Alencar, UFMG (Brazil)
Eduardo Duarte, CEFET-RJ (Brazil)
Celso Batalha, Observatorio Nacional (Brazil)
Dalton Lopes, Observatorio Nacional (Brazil)

We present the analysis of 18 spectrophotometric observations of the
classical T Tauri star GQ Lup A (K7) obtained with the Boller and
Chivens spectrograph at the 1.52 m ESO telescope.  We determined the
rotational velocity of GQ Lup A (vsini = 8 +- 2 km/s), measured the
veiling and calculated the stellar extinction (Av = 0.5 +- 0.1).  The
veiling was found to be variable and periodic at 11 days, which is
consistent with the photometric period of GQ Lup A.  The star exhibits
strong emission lines that show substantial variability in their
fluxes.  The emission line fluxes are strongly correlated but none
presented a good correlation with the veiling.  We compare our results
with the predictions of magnetospheric accretion models.  Recently,
Neuhauser et al.  (2005) found a co-moving sub-stellar companion to GQ
Lup A.  The interest has then grown to determine precise parameters,
such as age and distance, for GQ Lup A.  We determined the
photospheric flux of GQ Lup A for each observing night and obtained
the stellar radius (Rstar = 1.8 +- 0.3 Rsun), using the mean distance
of 150  +- 40  pc to the Lupus cloud.  Assuming a K7V temperature of
4060  K, the luminosity of GQ Lup is Lstar= 0.8 +- 0.3 Lsun.  Using
standard evolutionary models, we obtained Mstar= 0.8 +- 0.2 Msun and
an age of 3 +- 2 Myr.

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