SIMBAD references

2004A&A...414L..53T - Astronomy and Astrophysics, volume 414, L53-56 (2004/2-2)

L1521E: The first starless core with no molecular depletion.

TAFALLA M. and SANTIAGO J.

Abstract (from CDS):

L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we define to asses core evolution, and which compares the emission of the easily-depleted C18O molecule with that of the hard to deplete, late-time species N2H+. While all cores we have studied so far have R ratio lower than 1, L1521E has an R value of 3.4, which is 8 times the mean of the other cores. To understand this difference, we have modeled the C18O and N2H+ abundance profiles in L1521E using a density distribution derived from 1.2 mm continuum data. Our model shows that the C18O emission in this core is consistent with constant abundance, and this makes L1521E the first core with no C18O depletion. Our model also derives an unusually low N2H+ abundance. These two chemical peculiarities suggest that L1521E has contracted to its present density very recently, and it is therefore an extremely young starless core. Comparing our derived abundances with a chemical model, we estimate a tentative age of ≤1.5x105yr, which is too short for ambipolar diffusion models.

Abstract Copyright:

Journal keyword(s): ISM: abundances - ISM: clouds - ISM: molecules - stars: formation - ISM: individual: L1521E

Status at CDS:  

CDS comments: Fig.1 : L981-1 = NAME LDN 981 1, L234E-1 = NAME LDN 234E 1, L694-2 = NAME LDN 694 2.

Simbad objects: 18

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2020.04.06-13:58:59

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