The hot core that is not a “Hot Core”: Orion KL Luis Zapata (MPIfR) Johannes Schmid-Burgk (MPIfR) Karl Menten (MPIfR) Max Planck Institut für Radioastronomie

The BN/KL outflow An enigmatic flow associated with a star forming region Reported for the first time by Allen and Burton (1993) and Taylor (1994) Orion BN/KL Trapezium Orion `South Lbol~105 Lsun (Orion BN/KL) M ~ 10 Msun E ~ 1047 Erg High vel. >100 km s-1 Very poor collimated Bright in optical and infrared bands Subaru Infrared Telescope

No a common outflow: Explosive disintegration of a massive young stellar system BN n I Gaussian fitting A common center SMA CO(2-1) & H2 Red: 35 to 130 km s-1 Blue: -35 to -120 km s-1 Zapata et al. (2009) Rodriguez et al. (2005) Gomez et al. (2006)

An isotropic explosive flow? CO(2-1) – high velocity gas ~ 40 filaments

3D Movie Age = 500 yrs

Southeastern parts also fainter Subaru Infrared Telescope J, K’, H2

? Chernin & Wright (1996) CO(1-0) & HCN Outflow model Orion KL Hot core

The famous Orion-KL Hot Core A peculiar hot core “Heart-shaped” First discovered “hot core” (Ho et al. 1979) Orion South Compact Hot Cores Wilson et al. (2000) NH3 (4,4) N(H2) > 1023 cm2 Tdust ~ 200 K Zapata et al. (2004) CH3CN & 1.3 mm

Chemical and velocity diversity IRc 6 Hot core Friedel and Snyder (2007) CARMA Guélin et al. (2007) IRAM 30

What is putting the hot in the Orion KL Hot Core? See for a more complete debate: Blake et al. (1996), Liu et al. (2002), and de Vicente et al .(2002) Radio sources NH3 Mid-infrared SHUPING et al (2004) Menten & Reid (1995)

The Submillimeter Array Millimeter and submillimeter molecular and continuum observations Moderate angular resolution ~ 3-4” Hot molecular tracers: mainly vibrational excited emission.

CH3CN k=3 -- SMA 880 μm – SCUBA-JCMT CO(2-1) & H2 A close relation between the Hot Core and the explosive flow CH3CN k=3 -- SMA 880 μm – SCUBA-JCMT CO(2-1) & H2

SMA CO(3-2) filaments vs. Position Angle

Simple model of the Hot Core Orion KL Hot Core Simple model of the Hot Core Internally Cold molecular gas Hot molecular gas Obscured Protostar: Centimeter Submillimiter Infrared Externally (outflow, stars)

Where is the hot molecular gas within the Orion’s core? Torsionally and vibrationally excited lines

Where is the hot molecular gas within the core?

The Orion’s heart: CH3CN lines

Midinfrared, molecular, centimeter and submillimeter emission

Kinematics of the molecular gas in hot core: Filaments !

Summary A good correlation exists between the absence of CO filamentary flow structures or “fingers” and the area behind the position of the Orion KL Hot Core. The torsionally/vibrationally excited lines and CH3CN(12-11), all of which are supposed to trace hot and dense molecular gas, are located toward the northeast lobe of the “heart” structure. The HC3N(37-36)(v7=1) and CH3OH(74,3-63,3) A− (vt=1) lines appear to form a shell around the strongest submillimeter compact source. The CH3CN(123-113) and HC3N(37-36)(7=1) maps of the kinematics of the molecular gas within the Hot Core surprisingly reveal filament-like structures pointing toward the dynamical origin. The hottest molecular emission coincides well with a chain of mid-infrared (IRS2a-d) and OH maser emission, suggesting that part of the infrared emission of the Orion KL region maybe is generated by strong shocks. All of these observations suggest the southeast and southwest sectors of the explosive flow to have impinged on a pre-existing very dense part of the Extended Ridge, thus creating the bright Orion KL Hot Core.