INVESTIGADORES
MILLER BERTOLAMI Marcelo Miguel
artículos
Título:
Asteroseismological coinstrains on the pulsating planetary nebula nucleus (PG1159-type) RX J2117+3412.
Autor/es:
A. H. CORSICO; L. G. ALTHAUS; M. M. MILLER BERTOLAMI; K. WERNER.
Revista:
ASTRONOMY AND ASTROPHYSICS
Editorial:
EDP Sciences
Referencias:
Lugar: Paris; Año: 2007 vol. 461 p. 1095 - 1102
ISSN:
0004-6361
Resumen:
Aims.We present asteroseismological inferences on RX J2117.1+3412, the hottest known pulsating PG 1159 star. Our results are based on full PG 1159 evolutionary models recently presented by Miller Bertolami & Althaus (2006). Methods: We performed extensive computations of adiabatic g-mode pulsation periods on PG 1159 evolutionary models with stellar masses ranging from 0.530 to 0.741~Mȯ. PG 1159 stellar models are extracted from the complete evolution of progenitor stars started from the ZAMS, through the thermally pulsing AGB and born-again phases to the domain of the PG 1159 stars. We constrained the stellar mass of RX J2117.1+3412 by comparing the observed period spacing with the asymptotic period spacing and with the average of the computed period spacings. We also employed the individual observed periods to find a representative seismological model for RX J2117.1+3412. Results: We derive a stellar mass M_* 0.56-0.57~Mȯ from the period spacing data alone. In addition, we found a best-fit model representative for RX J2117.1+3412 with an effective temperature T_eff= 163 400 K, a stellar mass M_*= 0.565~Mȯ, and a surface gravity log g= 6.61. The derived stellar luminosity and radius are log (L_*/Lȯ)= 3.36 and log (R_*/Rȯ)= -1.23, respectively, and the He-rich envelope thickness is Menv= 0.02~Mȯ. We derive a seismic distance d 452 pc and a linear size of the planetary nebula D_PN 1.72 pc. These inferences seem to solve the discrepancy between the RX J2117.1+3412 evolutionary timescale and the size of the nebula. All of the seismological tools we use concur to the conclusion that RX J2117.1+3412 must have a stellar mass M_* 0.565~Mȯ, much in agreement with recent asteroseismology studies and in clear conflict with the predictions of spectroscopy plus evolutionary tracks.
