Seeds of Life in Space (SOLIS)

Abstract

Aims. The Seeds Of Life In Space IRAM/NOEMA large program aims at studying a set of crucial complex organic molecules in a sample of sources with a well-known physical structure that covers the various phases of solar-type star formation. One representative object of the transition from the prestellar core to the protostar phases has been observed toward the very low luminosity object (VeLLO) L1521F. This type of source is important to study to link prestellar cores and Class 0 sources and also to constrain the chemical evolution during the process of star formation. Methods. Two frequency windows (81.6–82.6 GHz and 96.65–97.65 GHz) were used to observe the emission from several complex organics toward the L1521F VeLLO. These setups cover transitions of ketene (H2CCO), propyne (CH3CCH), formamide (NH2CHO), methoxy (CH3O), methanol (CH3OH), dimethyl ether (CH3OCH3), and methyl formate (HCOOCH3). Results. Only two transitions of methanol (A+, E2) have been detected in the narrow window centered at 96.7 GHz (with an upper limit on E1) in a very compact emission blob (~7′′ corresponding to ~1000 au) toward the northeast of the L1521F protostar. The CS 2–1 transition is also detected within the WideX bandwidth. Consistently with what has been found in prestellar cores, the methanol emission appears ~1000 au away from the dust peak. The location of the methanol blob coincides with one of the filaments that have previously been reported in the literature. The excitation temperature of the gas inferred from methanol is (10 ± 2) K, while the H2 gas density (estimated from the detected CS 2–1 emission and previous CS 5–4 ALMA observations) is a factor >25 higher than the density in the surrounding environment (n(H2) ≥ 107 cm−3). Conclusions. Based on its compactness, low excitation temperature, and high gas density, we suggest that the methanol emission detected with NOEMA is (i) either a cold and dense shock-induced blob that formed recently (≤ a few hundred years) by infalling gas or (ii) a cold and dense fragment that may just have been formed as a result of the intense gas dynamics within the L1521F VeLLO system.

Discovery of Asymmetric Spike-like Structures of the 10 au Disk around the Very Low-luminosity Protostar Embedded in the Taurus Dense Core MC 27/L1521F with ALMA

“…If the rings and arcs were formed due to interchange instability, the interior would be a cavity with low gas density but a strong magnetic field. The leaked gas collides with the circumstellar material, and shocks should occur at the (inner) edge of the rings and arcs, consistent with the observed characteristics of higher temperatures inside the arcs (Figures 2 and 3) and the partial detection of shock-related tracers such as SO and methanol (Favre et al 2020). Meanwhile, the arcs themselves expand outward on the order of the sound speed, c s (Zhao et al 2011;Matsumoto et al 2017).…”

FAUST. II. Discovery of a Secondary Outflow in IRAS 15398−3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?

“…For instance, protostellar accretion bursts resulting in a large instantaneous increase in the protostellar luminosity and subsequent heating of the protostellar envelope have been suggested for Class 0 sources based on the observed spatial distribution of molecular species (Jørgensen et al 2013;Hsieh et al 2018Hsieh et al , 2019. Furthermore, complex structure, consisting of arc-like features and dense clumps, has been reported around the very young protostellar core, L1521F (Tokuda et al 2014;Favre et al 2020), and for the first hydrostatic core candidate, Chamaeleon-MMS1 (Busch et al 2020). Because the protostars are deeply embedded in their parent cores, interactions between a protostellar outflow and surrounding gas may contribute to such complicated morphologies.…”

Experimental Simulation of Fast Electron Bombardment of Methanol Ice and Its Implications in Astrochemistry

“…Subsequent detections were achieved in dense molecular clouds (Irvine et al, 1987;Tielens & Allamandola, 1987). More recently, significant milestones in methanol detection include its observation in the circumstellar gas of a proto-star, TW Hya, measured using the Atacama Large Millimeter Array (ALMA) (Walsh et al, 2016), and the identification of a methanol concentration in a prestellar core during the protostellar phases within a Very Low Luminosity Object (VeLLO) known as L1521F (Favre et al, 2020).…”