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In 2010 a sub-stellar companion to the solar analog pre-main sequence star PZTel and member of the about 12 Myr old Beta Pic moving group was found byhigh-contrast direct imaging independently by two teams. In order to determinethe basic parameters of this companion more precisely and independent ofevolutionary models, hence age independent, we obtained follow-up spectroscopicobservations of primary and companion. We use the Spectrograph for INtegralField Observations in the Near Infrared (SINFONI) at the Very Large TelescopeUnit 4/YEPUN of ESO's Paranal Observatory in H+K band and process the datausing the spectral deconvolution technique. The resulting spectrum of thecompanion is then compared to a grid of Drift-Phoenix synthetic model spectra,a combination of a general-purpose model atmosphere code with anon-equilibrium, stationary cloud and dust model, using a chi^2 minimizationanalysis. We find a best fitting spectral type of G6.5 for PZ Tel A. Theextracted spectrum of the sub-stellar companion, at a spatial positioncompatible with earlier orbit estimates, yields a temperature Teff= 2500+138-115 K, a visual extinction A_V= 0.53 +0.84-0.53 mag, a surface gravity oflog g= 3.50 +0.51-0.30 dex, and a metallicity at the edge of the grid of [M/H]=0.30 -0.30 dex. We derive a luminosity of log(Lbol/Lsun)= -2.66 +0.06-0.08, aradius of R= 2.42 +0.28-0.34 R_Jup and a mass of M= 7.5 +16.9-4.3 M_Jup for thePZ Tel companion, being consistent with most earlier estimates using photometryalone. Combining our results with evolutionary models, we find a best fittingmass of about 21 Jupiter masses at an age corresponding to the recentlydetermined lithium depletion age of 7 +4-2 Myr. Hence, the PZ Tel companion ismost likely a wide brown dwarf companion in the 12 +8-4 Myr old Beta Pic movinggroup.

First spectroscopic observations of the sub-stellar companion of the young debris disk star PZ Telescopii