2009A&A...495..837G


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.28CET09:34:11

2009A&A...495..837G - Astronomy and Astrophysics, volume 495, 837-846 (2009/3-1)

Lack of PAH emission toward low-mass embedded young stellar objects.

GEERS V.C., VAN DISHOECK E.F., PONTOPPIDAN K.M., LAHUIS F., CRAPSI A., DULLEMOND C.P. and BLAKE G.A.

Abstract (from CDS):

Polycyclic aromatic hydrocarbons (PAHs) have been detected toward molecular clouds and some young stars with disks, but have not yet been associated with embedded young stars. We present a sensitive mid-infrared spectroscopic survey of PAH features toward a sample of low-mass embedded young stellar objects (YSOs). The aim is to put constraints on the PAH abundance in the embedded phase of star formation using radiative transfer modeling. VLT-ISAAC L-band spectra for 39 sources and Spitzer IRS spectra for 53 sources are presented. Line intensities are compared to recent surveys of Herbig Ae/Be and T Tauri stars. The radiative transfer codes RADMC and RADICAL are used to model the PAH emission from embedded YSOs consisting of a pre-main-sequence star with a circumstellar disk embedded in an envelope. The dependence of the PAH feature on PAH abundance, stellar radiation field, inclination and the extinction by the surrounding envelope is studied. The 3.3µm PAH feature is undetected for the majority of the sample (97%), with typical upper limits of 5x10–16W/m2. One source originally classified as class I, IRS 48, shows a strong 3.3µm feature from a disk. Compact 11.2µm PAH emission is seen directly towards 1 out of the 53 Spitzer Short-High spectra, for a source that is borderline embedded. For all 12 sources with both VLT and Spitzer spectra, no PAH features are detected in either. In total, PAH features are detected toward at most 1 out of 63 (candidate) embedded protostars (≲2%), even lower than observed for class II T Tauri stars with disks (11-14%). Models predict the 7.7µm feature as the best tracer of PAH emission, while the 3.3µm feature is relatively weak. Assuming typical class I stellar and envelope parameters, the absence of PAH emission is most likely explained by the absence of emitting carriers through a PAH abundance at least an order of magnitude lower than in molecular clouds but similar to that found in disks. Thus, most PAHs likely enter the protoplanetary disks frozen out in icy layers on dust grains and/or in coagulated form.

Abstract Copyright:

Journal keyword(s): stars: pre-main sequence - stars: planetary systems: protoplanetary disks - stars: circumstellar matter - astrochemistry

Simbad objects: 89

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Number of rows : 89

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME LDN 1448 IRS 1 Em* 03 25 09.430 +30 46 21.58     19.5     ~ 88 0
2 LDN 1448NA smm 03 25 36.49 +30 45 22.2           ~ 173 1
3 SSTc2d J032536.4+304522 Y*O 03 25 36.49 +30 45 22.2           ~ 187 1
4 NAME LDN 1455 IRS 1 cor 03 27 39.08 +30 13 03.1           ~ 143 0
5 NAME LDN 1455 IRS 4 cor 03 27 43.23 +30 12 28.9           ~ 63 0
6 2MASS J03280041+3008012 Y*O 03 28 00.411 +30 08 01.28           ~ 45 0
7 2MASS J03283450+3100510 Y*O 03 28 34.501 +31 00 51.01           ~ 69 0
8 IRAS 03271+3013 cor 03 30 15.159 +30 23 49.38           ~ 60 0
9 IRAS 03301+3111 cor 03 33 12.8441374518 +31 21 24.130538910           K0-M3 53 0
10 2MASS J03331667+3107548 Y*O 03 33 16.68 +31 07 54.9           ~ 103 2
11 JCMTSE J033317.8+310932 cor 03 33 17.85 +31 09 31.9           ~ 79 0
12 SSTc2d J033327.2+310710 cor 03 33 27.29 +31 07 10.2           ~ 45 0
13 NAME HH 211-mm Y*O 03 43 56.816 +32 00 50.06           ~ 57 1
14 2MASS J03470544+3243084 Y*O 03 47 05.447 +32 43 08.43           ~ 51 0
15 IRAS 03445+3242 Y*O 03 47 41.603 +32 51 43.79           ~ 175 0
16 IRAS 04016+2610 Y*O 04 04 43.07064 +26 18 56.3904           ~ 239 0
17 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3618 0
18 ISOY J053513.81-052340.1 Y*O 05 35 13.7814 -05 23 39.990           ~ 29 0
19 MLLA 293 Y*O 05 35 14.3976 -05 23 50.914           ~ 27 0
20 RAFGL 5163 Y*O 05 40 27.45024 -07 27 30.0564           ~ 126 1
21 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 299 1
22 IRAS 08261-5100 MoC 08 27 38.9 -51 10 38           ~ 29 0
23 IRAS 08476-4306 cor 08 49 25.9 -43 17 10           ~ 27 0
24 [MHL2007] G264.9032+01.6584 1 Y*? 08 59 26.41 -43 26 13.4           ~ 10 0
25 HH 75 HH 09 11 38.5 -45 42 28           ~ 19 0
26 IRAS 11051-7706 Y*O 11 06 46.025 -77 22 29.67           ~ 71 0
27 [PMG2001] NIR 76 Y*? 11 06 46.580 -77 22 32.56           ~ 55 0
28 V* HP Cha Or* 11 08 15.216432 -77 33 53.17020   14.33 12.77 12.11   K3+G5e 101 0
29 V* HP Cha A * 11 08 15.4942983813 -77 33 53.454218639           K6e 81 0
30 NAME Cha IR Nebula TT* 11 08 38.702 -77 43 51.54           M5.5 72 0
31 OTS 18 IR 11 09 36.6 -76 33 39           ~ 8 0
32 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 704 0
33 2MASS J12590656-7707401 Y*O 12 59 06.56 -77 07 40.1           K4.5 47 0
34 CG 12 CGb 13 57 42.2 -39 56 21           ~ 48 1
35 Barnard 228 cor 15 43 00.9 -34 08 48           ~ 64 0
36 IRAS 15398-3359 Y*? 15 43 02.21016 -34 09 07.7112       18.38 21.72 ~ 131 0
37 Elia 2-20 TT* 16 26 18.8782824640 -24 28 19.698059817           ~ 97 1
38 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 200 1
39 GSS 32 TT* 16 26 24.0521249616 -24 24 48.105099750       17.81 15.58 K5-K6 98 1
40 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 377 0
41 [SSG2006] MMS002 smm 16 26 26.50 -24 24 30.9           ~ 241 0
42 YLW 35 Y*O 16 26 31.03680 -24 31 05.2248           ~ 21 1
43 VSSG 30 Y*O 16 26 44.19504 -24 34 48.3492           ~ 129 0
44 JCMTSF J162706.3-243702 PoC 16 27 06.5 -24 37 12           ~ 17 0
45 WLY 1-43 Y*O 16 27 11.17992 -24 40 46.6680           ~ 56 0
46 WL 19 Y*O 16 27 11.71416 -24 38 32.0604           ~ 68 0
47 NAME WL 20S BD? 16 27 15.69 -24 38 45.7           ~ 13 0
48 WL 20 Y*O 16 27 15.69840 -24 38 43.4364           ~ 78 0
49 NAME WL 20E Y*O 16 27 15.87648 -24 38 43.3896           ~ 71 0
50 YLW 12A Y*O 16 27 17.57160 -24 28 56.2944           ~ 66 0
51 YLW 13B Y*O 16 27 21.46872 -24 41 43.0692           ~ 88 0
52 WL 6 Y*O 16 27 21.80448 -24 29 53.3616           ~ 113 0
53 CRBR 2422.8-3423 Y*O 16 27 24.61320 -24 41 03.4080           ~ 83 1
54 YLW 15 Y*O 16 27 26.93640 -24 40 50.8224           ~ 242 1
55 YLW 16A Y*O 16 27 28.02744 -24 39 33.5052           K8 185 0
56 Elia 2-32 Y*O 16 27 28.44576 -24 27 21.0348           K6.5 106 1
57 YLW 16B Y*O 16 27 29.43528 -24 39 16.1892           ~ 103 0
58 Elia 2-33 Y*O 16 27 30.18024 -24 27 43.3656           M2 111 1
59 IRAS 16245-2423 TT* 16 27 37.1911764648 -24 30 35.031583716       16.66 14.67 B5-F2 243 0
60 YLW 45 Y*O 16 27 39.82824 -24 43 15.0672           ~ 110 0
61 YLW 52 Y*O 16 27 51.80472 -24 31 45.5304           ~ 64 0
62 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3115 1
63 IRAS 16285-2355 Y*O 16 31 35.65752 -24 01 29.4708           ~ 106 0
64 ISO-Oph 204 TT* 16 31 52.1212410606 -24 56 15.712413458           ~ 38 0
65 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1072 1
66 NAME IRAS 16293-2422B Y*O 16 32 22.63 -24 28 31.8           ~ 195 0
67 HBC 650 TT* 16 34 29.32 -15 47 01.4           K3.0 165 2
68 HBC 671 Em* 18 29 01.8367751476 +00 29 54.753564712   18.4       K0: 25 0
69 IRAS 18267+0016 Y*O 18 29 16.1808329339 +00 18 21.995909986       21.0   K7: 15 0
70 SH 2-68 N Y*O 18 29 48.09 +01 16 45.0           ~ 109 1
71 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 945 2
72 2MASS J18295433+0115017 Y*O 18 29 54.34 +01 15 01.8           ~ 10 0
73 2MASS J18295655+0112596 Y*O 18 29 56.553 +01 12 59.65           ~ 22 0
74 2MASS J18295667+0112393 Y*O 18 29 56.674 +01 12 39.32           ~ 19 0
75 HBC 672 Em* 18 29 56.8828626544 +01 14 46.339137067   17.6       K8.0 100 0
76 NAME Serpens SMM 4 cor 18 29 57.1 +01 13 15           ~ 125 0
77 [EC89] SVS 4-5 Y*O 18 29 57.59 +01 13 00.6           ~ 32 1
78 2MASS J18295760+0113004 Y*O 18 29 57.602 +01 13 00.42           ~ 35 3
79 IRAS 18274+0112 Y*O 18 29 57.73680 +01 14 05.6940           M4: 137 2
80 2MASS J18295785+0112514 Y*O 18 29 57.858 +01 12 51.40           ~ 59 3
81 [CED93] 4E smm 18 29 58.1 +01 13 15           ~ 2 0
82 NAME SERPENS SMM 3 smm 18 29 59.7 +01 14 00           ~ 86 1
83 CHLT 3 * 19 01 48.10 -36 57 22.7           K6V 30 0
84 CHLT 4 * 19 01 48.15 -36 57 22.3           ~ 14 0
85 V* V710 CrA Or* 19 01 50.67792 -36 58 09.6132           K7: 118 0
86 2MASS J19015545-3657231 Y*O 19 01 55.460 -36 57 23.13           ~ 91 2
87 [NWA2005] SMM 1B Y*O 19 01 56.41 -36 57 28.0           ~ 82 1
88 IRAS 18595-3712 Y*O 19 02 58.706 -37 07 34.67           ~ 43 0
89 PSCz Q23238+7401 Y*O 23 25 46.65 +74 17 37.2           ~ 54 1

    Equat.    Gal    SGal    Ecl

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2021.01.28-09:34:11

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