2014A&A...572A..24W


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.13CEST06:45:52

2014A&A...572A..24W - Astronomy and Astrophysics, volume 572A, 24-24 (2014/12-1)

Observations of nitrogen isotope fractionation in deeply embedded protostars.

WAMPFLER S.F., JORGENSEN J.K., BIZZARRO M. and BISSCHOP S.E.

Abstract (from CDS):

The terrestrial planets, comets, and meteorites are significantly enriched in 15N compared to the Sun and Jupiter. While the solar and jovian nitrogen isotope ratio is believed to represent the composition of the protosolar nebula, a still unidentified process has caused 15N-enrichment in the solids. Several mechanisms have been proposed to explain the variations, including chemical fractionation. However, observational results that constrain the fractionation models are scarce. While there is evidence of 15N-enrichment in prestellar cores, it is unclear how the signature evolves into the protostellar phases. The aim of this study is to measure the 14N/15N ratio around three nearby, embedded low- to intermediate-mass protostars. Isotopologues of HCN and HNC were used to probe the 14N/15N ratio. A selection of J=3-2 and 4-3 transitions of H13CN, HC15N, HN13C, and H15NC was observed with the Atacama Pathfinder EXperiment telescope (APEX). The 14N/15N ratios were derived from the integrated intensities assuming a standard 12C/13C ratio. The assumption of optically thin emission was verified using radiative transfer modeling and hyperfine structure fitting. Two sources, IRAS 16293A and R CrA IRS7B, show 15N-enrichment by a factor of ∼1.5-2.5 in both HCN and HNC with respect to the solar composition. IRAS 16293A falls in the range of typical prestellar core values. Solar composition cannot be excluded for the third source, OMC-3 MMS6. Furthermore, there are indications of a trend toward increasing 14N/15N ratios with increasing outer envelope temperature. The enhanced 15N abundances in HCN and HNC found in two Class 0 sources (14N/15N∼160-290) and the tentative trend toward a temperature-dependent 14N/15N ratio are consistent with the chemical fractionation scenario, but 14N/15N ratios from additional tracers are indispensable for testing the models. Spatially resolved observations are needed to distinguish between chemical fractionation and isotope-selective photochemistry.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: abundances - ISM: molecules - stars: formation - stars: general

Simbad objects: 27

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Number of rows : 27

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 390 3
2 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 596 1
3 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 465 0
4 NGC 1333 OpC 03 29 11 +31 18.6           ~ 1219 1
5 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 553 0
6 Barnard 1 MoC 03 33 16.3 +31 07 51           ~ 257 0
7 [HKM99] B1-b cor 03 33 20.32 +31 07 21.5           ~ 158 0
8 LDN 1498 DNe 04 11.0 +24 58           ~ 247 0
9 LDN 1521F DNe 04 28 39.3 +26 51 43           ~ 183 1
10 NAME [BM89] L1521E DNe 04 29 21.0 +26 14 19           ~ 85 1
11 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 681 0
12 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2001 1
13 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 716 0
14 [TSO2008] 14 mm 05 35 23.420 -05 01 30.35           ~ 57 0
15 TKK 870 Y*O 05 35 28.19 -05 03 41.2           ~ 34 0
16 [PCW91] Ced 110 IRS 10 Y*O 11 06 33.38 -77 23 34.6           ~ 58 1
17 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 682 1
18 Elia 2-29 Y*O 16 27 09.43032 -24 37 18.7716           ~ 267 1
19 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3027 0
20 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1035 1
21 NAME IRAS 16293-2422A Y*O 16 32 22.869 -24 28 36.11           ~ 107 0
22 LDN 1689N DNe 16 32 31 -24 28.6           ~ 108 0
23 IRAS 17233-3606 HII 17 26 42.8 -36 09 17           ~ 67 0
24 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11542 0
25 V* R CrA Ae* 19 01 53.6850227874 -36 57 08.145519972 12.781 12.651 11.917 11.242 10.412 B5IIIpe 449 1
26 [NWA2005] SMM 1B Y*O 19 01 56.41 -36 57 28.0           ~ 78 1
27 GRS G081.70 +00.50 SFR 20 39 01.6 +42 19 38           O4.5 944 0

    Equat.    Gal    SGal    Ecl

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2020.07.13-06:45:52

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