EPoS Contribution
EPoS Contribution
Outflow and Envelope Properties of the Archetype First Hydrostatic Core Candidate L1451-mm

Maria Maureira
Yale, New Haven, US
For nearly 50 years the first hydrostatic core (FHSC) stage has been produced in simulations of low-mass star formation, however, it has not been observationally identified. Observational identification of the FHSC is of prime importance in our understanding of the early evolution of dense cores and the formation of low-mass stars, as it will test the predictions of (and set strong constraints on) numerical simulations of core collapse, protostar and outflow formation as well as the initial conditions for circumstellar disk growth and fragmentation. Simulations show that there are subtle differences in observational properties between first cores and young protostars (e.g., SED; outflow properties such as morphology, velocity, and temperature; chemical properties; presence/absence of a large disk) that can, in principle, allow us to discriminate between these two early stages of evolution. In this contribution, I will present interferometric observations of molecular emission lines towards the first core candidate L1451-mm. This candidate shows a poorly collimated, low velocity outflow with a lobe-size of ~500 AU in CO and CH3OH observations. H13CO+(1-0) emission shows no prominent peak at the continuum location, implying that the CO remains depleted towards this source. The NH2D and N2H+ kinematics are consistent with an envelope that is infalling and rotating with conservation of angular momentum around a compact object with mass <0.06 Msun, which suggests an age of just 10,000 years. Based on these observed physical and chemical properties, we propose L1451-mm as an archetype FHSC candidate. I will also show similar observations towards other first core candidates, to explore similarities and differences that can be attributed to different initial conditions.
Caption: Molecular emission line observations towards the first core candidate L1451-mm. (a) Central velocity maps. The blue and red arrow shows the red and blue outflow lobes direction and approximate extent. (b) NH2D position-velocity diagram, at a cut perpendicular to the outflow direction. (c) CH3OH ALMA observations. (d) ALMA H13CO+ and CH3OH integrated intensity.
Collaborators:
H. Arce, Yale, US
M. Dunham, SUNY, US
J. Pineda, MPE, DE
X. Chen, CAS, CN
T. Bourke, JBO, UK
Suggested Session: Cores