Photoionized Herbig–Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy – I. HH 529 II and III

6 A photoionized Herbig - Haro object in the Orion nebula

The spectra of Herbig Haro objects are usually characteristic of ionization and excitation in shock-heated gas, whether an internal shock in an unsteady outflow or a bow shock interface with the interstellar medium. We examine the eastern-most shock – the leading optically visible shock – of a Herbig Haro outflow (HH 529) seen projected on the face of the Orion Nebula, using deep optical echell...

Externally Illuminated Young Stellar Objects in the Orion Nebula

The circumstellar material surrounding most low-mass young stars in the Orion Nebula Cluster is rendered visible by the ionizing radiation of the hot Trapezium stars and the background light of M42. I discuss Hubble Space Telescope observations of these lower mass young stellar objects and their environments. Photoionization of circumstellar material by 1Ori C produces a bright cusp-shaped ioni...

Herbig Haro Objects in the Orion Nebula 1

Infrared Spectroscopy of Substellar Objects in Orion

We present broad band spectra of a sample of 21 low luminosity sources in the Trapezium Cluster, with masses in the range 0.008-0.10 M ⊙ (assuming an age of 1 Myr). These were selected for low extinction in most cases and are located west of the brighter nebulosity. The spectra are in the H bandpass (1.4-1.95 µm) and K bandpass (1.9-2.5 µm) also for most of the brighter sources, with a resoluti...

Star Formation in the Orion Nebula I : Stellar Content

The Orion Nebula is one of the most frequently observed nearby (< 1 kiloparsec) star forming regions and, consequently, the subject of a large bibliography of observations and interpretation. The summary in this chapter is bounded spatially by the blister HII region, with sources beyond the central nebula that are part of the same dynamical clustering covered in other chapters in this book. Her...