Mass ejection and time variability in protostellar outflows: Cep E. SOLIS XVI
Creators: name: Schutzer, A. de A.
name: Rivera-Ortiz, P. R.
name: Lefloch, B.
name: Gusdorf, A.
name: Favre, C.
name: Segura-Cox, D.
name: Lopez-Sepulcre, A.
name: Neri, R.
name: Ospina-Zamudio, J.
name: De Simone, M.
name: Codella, C.
name: Viti, S.
name: Podio, L.
name: Pineda, J.
name: O'Donoghue, R.
name: Ceccarelli, C.
name: Caselli, P.
name: Alves, F.
name: Bachiller, R.
name: Balucani, N.
name: Bianchi, E.
name: Bizzocchi, L.
name: Bottinelli, S.
name: Caux, E.
name: Chacón-Tanarro, A.
name: Dulieu, F.
name: Enrique-Romero, J.
name: Fontani, F.
name: Feng, S.
name: Holdship, J.
name: Jiménez-Serra, I.
name: Al-Edhari, A. Jaber
name: Kahane, C.
name: Lattanzi, V.
name: Oya, Y.
name: Punanova, A.
name: Rimola, A.
name: Sakai, N.
name: Spezzano, S.
name: Sims, I. R.
name: Taquet, V.
name: Testi, L.
name: Theulé, P.
name: Ugliengo, P.
name: Vastel, C.
name: Vasyunin, A. I.
name: Vazart, F.
name: Yamamoto, S.
name: Witzel, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Protostellar jets are an important agent of star formation feedback, tightly connected with the mass-accretion process. The history of jet formation and mass-ejection provides constraints on the mass accretion history and the nature of the driving source. We want to characterize the time-variability of the mass-ejection phenomena at work in the Class 0 protostellar phase, in order to better understand the dynamics of the outflowing gas and bring more constraints on the origin of the jet chemical composition and the mass-accretion history. We have observed the emission of the CO 2-1 and SO N_J=5_4-4_3 rotational transitions with NOEMA, towards the intermediate-mass Class 0 protostellar system Cep E. The CO high-velocity jet emission reveals a central component associated with high-velocity molecular knots, also detected in SO, surrounded by a collimated layer of entrained gas. The gas layer appears to accelerate along the main axis over a length scale delta_0 ~700 au, while its diameter gradually increases up to several 1000au at 2000au from the protostar. The jet is fragmented into 18 knots of mass ~10^-3 Msun, unevenly distributed between the northern and southern lobes, with velocity variations up to 15 km/s close to the protostar, well below the jet terminal velocities. The knot interval distribution is approximately bimodal with a scale of ~50-80yr close to the protostar and ~150-200yr at larger distances &gt;12". The mass-loss rates derived from knot masses are overall steady, with values of 2.7x10^-5 Msun/yr (8.9x10^-6 Msun/yr) in the northern (southern) lobe. The interaction of the ambient protostellar material with high-velocity knots drives the formation of a molecular layer around the jet, which accounts for the higher mass-loss rate in the north. The jet dynamics are well accounted for by a simple precession model with a period of 2000yr and a mass-ejection period of 55yr.
description: 13 pages, 9 figures, 3 table. Accepted in A&amp;A