2004A&A...414L..53T


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.23CEST05:49:59

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

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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Number of rows : 18

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 LDN 1333 DNe 02 26 04 +75 28.5           ~ 49 0
2 LDN 1400K DNe 04 10 48.6 +54 53 14           ~ 30 0
3 NAME [BM89] L1498 PoC 04 10 51.4 +25 09 58           ~ 187 0
4 LDN 1498 DNe 04 11.0 +24 58           ~ 241 0
5 NAME [BM89] L1495 PoC 04 14 08.2 +28 09 31           ~ 170 0
6 LDN 1495 DNe 04 18.1 +27 37           ~ 274 1
7 NAME [BM89] L1521E DNe 04 29 21.0 +26 14 19           ~ 82 1
8 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1326 0
9 NAME [BM89] L1517B cor 04 55 18.8 +30 38 04           ~ 127 0
10 LDN 1512 MoC 05 04 09.7 +32 43 09           ~ 159 0
11 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 653 0
12 NAME [BM89] L1544 cor 05 04 22.5 +25 11 36           ~ 434 1
13 NAME [LM99] L234E-S cor 16 48 08.6 -10 57 25           ~ 13 0
14 LDN 663 DNe 19 36 55 +07 34.4           ~ 536 0
15 [LM99] L694-2 cor 19 41 04.6 +10 57 02           ~ 58 0
16 [LM99] L1155C1 cor 20 43 29.9 +67 52 42           ~ 9 0
17 [LM99] L981-1 cor 21 00 13.2 +50 20 06           ~ 10 0
18 LDN 1197 DNe 22 37 20 +58 56.1           ~ 29 0

    Equat.    Gal    SGal    Ecl

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2019.10.23-05:49:59

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