Precision SED Modeling of Massive Protostars

Principal Investigator

Yao-Lun Yang

Proposal ID

75_0116

Category

STAR_FORMATION

Keywords

• DUST
• H II REGIONS
• MASSIVE STARS
• SPECTROSCOPY
• STAR FORMATION

Abstract

Formation of massive stars is a prime driver of the evolution of galaxies. However, our understanding of massive star formation remains relatively poor compared to that of lower-mass counterparts. Modeling of spectral energy distributions (SEDs) is a powerful tool for constraining the properties of massive protostellar sources. However, coarse sampling of the SED results in significant degeneracies, limiting the accuracy of observational tests of theoretical models. Using FORCAST GRISM spectroscopy, we aim to obtain the highest precision and most comprehensive SEDs of a sample of massive protostars, which are already well-studied photometrically from the near- to far-IR. We propose to obtain spectra at 5-28 um, where critical features in synthetic SEDs are currently poorly sampled with only photometric data. This survey focuses on the brightest sources whose SEDs have been modeled with photometric data. The silicate absorption feature at 9.7 um and water ice feature ~6 um will provide critical constraints on the SEDs and astrochemical models of massive protostars. This program fills the gaps in the SEDs constructed from archival images taken by FORCAST, Spitzer, Herschel, as well as other facilities, enabling us to carry out the most precise modeling of massive protostars. These observations will measure the depth and shape of the silicate feature, which is a powerful constraint on SED models, as well as features of ice and PAH. The overall result will be a sample of the most massive protostars with precision SED measurements that will provide a benchmark for future theoretical model development.