EPoS Contribution
EPoS Contribution
Methanol in the inner 100 AU of the pristine jet/disk HH212 protostellar system

Silvia Leurini
MPIfR, Bonn, DE
The birth of a Sun-like star is a complex game played by several participants (hot corino, circumstellar disk, ejected material) whose respective roles are not yet entirely clear. In particular, the nature of the warm (~100 K) gas surrounding low-mass protostars and enriched by complex molecules is still not properly understood. Indeed, we still do not know whether hot corinos trace only the thermal evaporation of icy grain mantles or whether non-thermal ice desorption processes also contribute (sputtering in shocks, photodesorption along cavity walls..).
In this contribution, I will present ALMA observations of HH212, a Sun-like class 0 protostar driving a spectacular bipolar H2/SiO collimated jet. The data trace with unprecedented detail all crucial ingredients involved in the star-disk formation recipe, namely: (i) the dusty flattened envelope/disk (possibly in Keplerian rotation with radius 0.2"); (ii) the axial jet launched by it; (iii) the biconical outflow cavities; (iv) the parent infalling envelope; (v) the hot corino, the first ever detected in Orion on such spatial scales. In particular, I will focus on the properties of methanol, a key ingredient for the formation of complex molecules, here observed at scales of less than 100 AU. At least seven lines are detected with upper energies up to ~300 K implying a rotational temperature of ~100 K. The CH3OH kinematics and abundance will be compared with that of HDO as well as of another complex molecule such as CH3CHO.
Caption: Upper panel: The HH212 protostellar system as observed by ALMA-Band 7 (Codella et al. 2014). Blue/red contours plot the blue-/redshifted SiO(8-7) jet at ± 8 km s-1 from Vsys, overlaid on the 0.9 mm continuum (black contours). Bottom panel: Zoom-in of the central region: the CH3OH (16_(1,15) - 15_(2,14)) integrated emission (Leurini et al. in prep.) in the range ± 2 km s-1 from the rest velocity (black contours from 5 σ in steps of 2 sigma) overlaid on the SiO jet.
C. Codella, INAF-Arcetri, IT
S. Cabrit, LERMA-Paris, FR
F. Gueth, IRAM, FR
R. Bachiller, IGN Madrid, ES
C. Ceccarelli, IPAG, FR
F. Fontani, INAF-Arcetri, IT
A. Gusdorf, LERMA-Paris, FR
B. Lefloch, IPAG, FR
B. Nisini, INAF-Roma, IT
L. Podio, INAF-Arcetri, IT
M. Tafalla, IGN Madrid, ES
Suggested Session: Chemistry