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We have made mapping observations of L1551 IRS 5, L1551NE, L723, and L43 and single-point observations of IRAS 16293-2422 in the submillimeter CS (J = 7-6) and HCN (J = 4-3) lines with ASTE. Including our previous ASTE observations of L483 and B335, we found a clear linear correlation between the source bolometric luminosities and the total integrated intensities of the submillimeter lines (I_CS ~L_bol^0.92). The combined ASTE + SMA CS (7-6) image of L1551 IRS 5 exhibits an extended (~2000 AU) component tracing the associated reflection nebula at the west and southwest, as well as a compact (< 500 AU) component centered on the protostellar position. The emission peaks of the CS and HCN emissions in L1551 NE are not located at the protostellar position but offset (~1400 AU) toward the associated reflection nebula at the west. With the statistical analyses, we confirmed the opposite velocity gradients of the CS (7-6) emission to those of the millimeter lines along the outflow direction, which we reported in our early paper. The magnitudes of the submillimeter velocity gradients are estimated to be (9.7pm1.7) times 10-3 km s-1 arcsec-1 in L1551 IRS 5 and (7.6pm2.4) times 10-3 km s-1 arcsec-1 in L483. We suggest that the skewed submillimeter molecular emissions toward the associated reflection nebulae at a few thousands AU scale trace the warm (> 40 K) walls of the envelope cavities, excavated by the associated outflows and irradiated by the central protostars directly. The opposite velocity gradients along the outflow direction likely reflect the dispersing gas motion at the wall of the cavity in the envelopes perpendicular to the outflow.
Recent water line observations toward several low-mass protostars suggest low water gas fractional abundances in the inner warm envelopes. Water destruction by X-rays has been proposed to influence the water abundances in these regions, but the detai
Molecular jets are seen coming from the youngest protostars in the early phase of low-mass star formation. They are detected in CO, SiO, and SO at (sub)millimeter wavelengths down to the innermost regions, where their associated protostars and accret
Within low-mass star formation, water vapor plays a key role in the chemistry and energy balance of the circumstellar material. The Herschel Space Observatory will open up the possibility to observe water lines originating from a wide range of excita
We present theoretical predictions of the rotational line emission of deuterated water in low-mass protostar collapsing envelopes. The model accounts for the density and temperature structure of the envelope, according the inside-out collapse framewo
We derive the dense core structure and the water abundance in four massive star-forming regions which may help understand the earliest stages of massive star formation. We present Herschel-HIFI observations of the para-H2O 1_11-0_00 and 2_02-1_11 and