TY - JOUR
T1 - First spectroscopic observations of the substellar companion of the young debris disk star PZ Telescopii
AU - Schmidt, T.O.B.
AU - Mugrauer, M.
AU - Neuhäuser, R.
AU - Vogt, N.
AU - Witte, S.
AU - Hauschildt, P.H.
AU - Helling, Christiane
AU - Seifahrt, A.
N1 - T.O.B.S. and R.N. acknowledge support from the German National Science Foundation (Deutsche Forschungsgemeinschaft, DFG) in grant NE 515/30-1. N.V. acknowledges support by Comité Mixto ESO-Gobierno de Chile, as well as by the Gemini-CONICYT fund 32090027. Ch.H. highlights financial support of the European Community under the FP7 by an ERC starting grant.
PY - 2014/6/20
Y1 - 2014/6/20
N2 - Context. In 2010 a substellar companion to the solar analog pre-main sequence star PZ Tel and member of the approximately 12 Myr old beta Pic moving group was found by high-contrast direct imaging independently by two teams. Aims. In order to determine the basic parameters of this companion more precisely and independent of evolutionary models, hence age-independent, we obtained follow-up spectroscopic observations of the primary and companion. Methods. We used the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) at the Very Large Telescope Unit 4/Yepun of ESO's Paranal Observatory in the H + K band and processed the data using the spectral deconvolution technique. The resulting spectrum of the companion was then compared to a grid of DRIFT-PHOENIX synthetic model spectra, a combination of a general-purpose model atmosphere code with a non-equilibrium, stationary cloud and dust model, using a chi(2) minimization analysis. Results. We find a best fitting spectral type of G6.5 for PZ Tel A. The extracted spectrum of the substellar companion, at a spatial position compatible with earlier orbit estimates, yields a temperature T-eff = 2500(-115)(+138) K, a visual extinction A(V) = 0.53(-0.53)(+0.84) mag, a surface gravity of log g = 3.50(-0.30)(+0.51) dex, and a metallicity at the edge of the grid of [M/H] = 0.30(-0.30) dex. Conclusions. We derive a luminosity of log(L-bol/L-circle dot) = -2.66(-0.08)(+0.06), a radius of R = 2.42(-0.34)(+0.28) R-Jup, and a mass of M = 7.5(-4.3)(+16.9) M-Jup for the PZ Tel companion, which is consistent with most earlier estimates using photometry alone. Combining our results with evolutionary models, we find a best-fitting mass of about 21 Jupiter masses at an age corresponding to the recently determined lithium depletion age of 7(-2)(+4) Myr. Hence, the PZ Tel companion is most likely a wide brown dwarf companion in the 12(-4)(+8) Myr old beta Pic moving group.
AB - Context. In 2010 a substellar companion to the solar analog pre-main sequence star PZ Tel and member of the approximately 12 Myr old beta Pic moving group was found by high-contrast direct imaging independently by two teams. Aims. In order to determine the basic parameters of this companion more precisely and independent of evolutionary models, hence age-independent, we obtained follow-up spectroscopic observations of the primary and companion. Methods. We used the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI) at the Very Large Telescope Unit 4/Yepun of ESO's Paranal Observatory in the H + K band and processed the data using the spectral deconvolution technique. The resulting spectrum of the companion was then compared to a grid of DRIFT-PHOENIX synthetic model spectra, a combination of a general-purpose model atmosphere code with a non-equilibrium, stationary cloud and dust model, using a chi(2) minimization analysis. Results. We find a best fitting spectral type of G6.5 for PZ Tel A. The extracted spectrum of the substellar companion, at a spatial position compatible with earlier orbit estimates, yields a temperature T-eff = 2500(-115)(+138) K, a visual extinction A(V) = 0.53(-0.53)(+0.84) mag, a surface gravity of log g = 3.50(-0.30)(+0.51) dex, and a metallicity at the edge of the grid of [M/H] = 0.30(-0.30) dex. Conclusions. We derive a luminosity of log(L-bol/L-circle dot) = -2.66(-0.08)(+0.06), a radius of R = 2.42(-0.34)(+0.28) R-Jup, and a mass of M = 7.5(-4.3)(+16.9) M-Jup for the PZ Tel companion, which is consistent with most earlier estimates using photometry alone. Combining our results with evolutionary models, we find a best-fitting mass of about 21 Jupiter masses at an age corresponding to the recently determined lithium depletion age of 7(-2)(+4) Myr. Hence, the PZ Tel companion is most likely a wide brown dwarf companion in the 12(-4)(+8) Myr old beta Pic moving group.
KW - Brown dwarfs
KW - Stars: pre-main sequence
KW - Stars: atmospheres
KW - Planetary systems
KW - Planets and satellites: formation
KW - Stars: individual: PZ Tel
UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84902953073&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201321625
DO - 10.1051/0004-6361/201321625
M3 - Article
AN - SCOPUS:84902953073
SN - 0004-6361
VL - 566
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A85
ER -