Detailed spectroscopic analysis of the Trapezium cluster stars inside the Orion nebula

Abstract

We present the results of a spectroscopic analysis of the Trapezium cluster stars inside the Orion Nebula. The rotational velocities have been obtained using Fourier analysis method, finding agreement with values derived from the usual method, based on linewidth measurements. The rotational velocity derived for theta 1 Ori C through this method is consistent with the variability of some of its spectral features that have a period of 15.42 days. By means of the fit of H, HeI and HeII observed profiles with FASTWIND synthetic profiles, stellar parameters and wind characteristics have been derived. This methodology let us estimate the errors associated with these parameters. It is found that macroturbulence effects have to be included for a good fit to the HeI-II lines in the spectrum of theta 1 Ori C. By means of a very accurate study, oxygen abundances have been derived for the three B0.5V stars theta 1 Ori A, D and theta 2 Ori B. Final abundances are consistent with the nebular gas-phase results presented in Esteban et al. (2004) and are lower than those given by Cunha and Lambert (1994). Our results suggest a lower dust depletion factor of oxygen than previous estimations for the Orion nebula.

arXiv comment21 pages, 17 figures, 13 tables. To be published in Astronomy & Astrophysics

Cited by in corpus (15)

• The death of massive stars - I. Observational constraints on the progenitors of type II-P supernovae
• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• The VLT-FLAMES survey of massive stars: Evolution of surface N abundances and effective temperature scales in the Galaxy and Magellanic Clouds
• The VLT-FLAMES survey of massive stars: Mass loss and rotation of early-type stars in the SMC
• Tracing the young massive high-eccentricity binary system Theta 1 Orionis C through periastron passage
• Properties of the ionized gas in HH202. II: Results from echelle spectrophotometry with UVES
• Visual/infrared interferometry of Orion Trapezium stars: Preliminary dynamical orbit and aperture synthesis imaging of the Theta 1 Orionis C system
• Detection of a magnetic field on HD108: clues to extreme magnetic braking and the Of?p phenomenon
• On the maximum value of the cosmic abundance of oxygen and the oxygen yield
• B-type supergiants in the SMC: Rotational velocities and implications for evolutionary models
• Long-term monitoring of theta1 OriC: the spectroscopic orbit and an improved rotational period
• The ionizing radiation from massive stars and its impact on HII regions: results from modern model atmospheres
• New insights into the nature of the peculiar star theta Carinae
• Are oxygen and neon enriched in PNe and is the current solar Ne/O abundance ratio underestimated?
• Mid-Infrared diagnostics of metal-rich HII regions from VLT and Spitzer Spectroscopy of Young Massive Stars in W31