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An Improved HR Diagram for the Orion Trapezium Cluster by Fang, Min; Kim, Jinyoung Serena; Pascucci, Ilaria; Apai, Dániel is a scholarly article available to read on EtoBox.

What is An Improved HR Diagram for the Orion Trapezium Cluster about?

In this paper, we present a study of the Trapezium cluster in Orion. We analyze flux-calibrated VLT/MUSE spectra of 361 stars to simultaneously measure the spectral types, reddening, and the optical veiling due to accretion. We find that the extinction law from Cardelli et al. (1989) with a total-to-selective extinction value of $R_{\rm V}=$5.5 is more suitable for this cluster. For 68% of the sample the new spectral types are consistent with literature spectral types within 2 subclasses, but as expected, we derive systematically later types than the literature by one to two subclasses for the sources with significant accretion levels. Here we present an improved Hertzsprung-Russell (H-R) diagram of the Trapezium cluster, in which the contamination by optical veiling on spectral types and stellar luminosities has been properly removed. A comparison of the locations of the stars in the H-R diagram with the non-magnetic and magnetic pre-main sequence evolutionary tracks indicates an age of 1--2~Myr. The magnetic pre-main sequence evolutionary tracks can better explain the luminosities of the low-mass stars. In the H-R diagram, the cluster exhibits a large luminosity spread ($\sigma$(

Author

Fang, Min; Kim, Jinyoung Serena; Pascucci, Ilaria; Apai, Dániel

Published

2020

Language

EN