X-rays and protostars in the Trifid Nebula

The Trifid Nebula is a young H II region, recently rediscovered as a "pre-O rion" star-forming region, containing protostars undergoing violent mass ej ections visible in optical jets as seen in images from the Infrared Space O bservatory and the Hubble Space Telescope. We report the first X-ray observ ations of the Trifid Nebula using ROSAT and ASCA. The ROSAT image shows a d ozen X-ray sources, with the brightest X-ray source being the O7 star, HD 1 64492, which provides most of the ionization in the nebula. We also identif y 85 T Tauri star and young, massive star candidates from near-infrared col ors using the JHK(s) color-color diagram from the Two-Micron All-Sky Survey (2MASS). Ten X-ray sources have counterpart near-infrared sources. The 2MA SS stars and X-ray sources suggest there are potentially numerous protostar s in the young H II region of the Trifid. ASCA moderate-resolution spectros copy of the brightest source shows hard emission up to 10 keV with a clearl y detected Fe K line. The best model fit is a two-temperature (T = 1.2 x 10 (6) K and 39 x 10(6) K) thermal model with additional warm absorbing media. The hotter component has an unusually high temperature for either an O sta r or an H II region; a typical Galactic H II region could not be the primar y source for such hot temperature plasma and the Fe XXV line emission. We s uggest that the hotter component originates in either the interaction of th e wind with another object (a companion star or a dense region of the nebul a) or from flares from deeply embedded young stars.