Chemical survey of Class I protostars with the IRAM-30 m

Context. Class I protostars are a bridge between 0 (≤10 5 yr old), and II (≥10 6 yr) protoplanetary disks. Recent studies show gaps rings in the dust distribution of disks younger than 1 Myr, suggesting that planet formation may start already at stage. To understand what chemistry planets will inherit, it is crucial to characterize sources investigate how chemical complexity evolves from Aims. There two goals: (i) perform census molecular sample four protostars, (ii) compare data with compositions earlier later phases Sun-like star process. Methods. We performed IRAM-30 m observations 1.3 mm towards objects (L1489-IRS, B5-IRS1, L1455-IRS1, L1551-IRS5). The column densities detected species were derived assuming local thermodynamic equilibrium (LTE) or large velocity gradients (LVGs). Results. 27 species: C-chains, N-bearing species, S-bearing Si-bearing deuterated molecules, interstellar complex organic molecules (iCOMs; CH 3 OH, CN, CHO, HCOOCH ). Among members observed sample, L1551-IRS5 most chemically rich source. Different spectral profiles observed: narrow lines (~1 km s −1 ) all sources, broader (~4 L1551-IRS5, (iii) line wings due outflows (in Narrow c-C H 2 emission originates envelope temperatures 5–25 K sizes ~2′′−10′′. iCOMs reveal occurrence hot corino chemistry, OH CN originating compact (~0.′′15) warm ( T > 50 K) region. Finally, OCS S seem probe circumbinary L1455-IRS1 binary systems. deuteration terms elemental D/H envelopes is: ~10−70% (D CO/H CO), ~5−15% (HDCS/H CS), ~1−23% (CH DOH/CH OH). For we derive ~2% Conclusions. Carbon chain extended revealed sources. In addition, low-excitation methanol centered systemic velocity, an origin structure, plausibly UV-illuminated. abundance ratios respect measured comparable estimated stages (prestellar cores, protostars), found comets. our also consistent values for stages. These findings support inheritance scenario prestellar cores phase when forming.