2020A&A...637A..92G


Query : 2020A&A...637A..92G

2020A&A...637A..92G - Astronomy and Astrophysics, volume 637A, 92-92 (2020/5-1)

Angular momentum profiles of Class 0 protostellar envelopes.

GAUDEL M., MAURY A.J., BELLOCHE A., MARET S., ANDRE P., HENNEBELLE P., GALAMETZ M., TESTI L., CABRIT S., PALMEIRIM P., LADJELATE B., CODELLA C. and PODIO L.

Abstract (from CDS):


Context. Understanding the initial properties of star forming material and how they affect the star formation process is a key question. The infalling gas must redistribute most of its initial angular momentum inherited from prestellar cores before reaching the central stellar embryo. Disk formation has been naturally considered as a possible solution to this "angular momentum problem". However, how the initial angular momentum of protostellar cores is distributed and evolves during the main accretion phase and the beginning of disk formation has largely remained unconstrained up to now.
Aims. In the framework of the IRAM CALYPSO survey, we obtained observations of the dense gas kinematics that we used to quantify the amount and distribution of specific angular momentum at all scales in collapsing-rotating Class 0 protostellar envelopes.
Methods. We used the high dynamic range C18O (2-1) and N2H+ (1-0) datasets to produce centroid velocity maps and probe the rotational motions in the sample of 12 envelopes from scales ∼50 to ∼5000au.
Results. We identify differential rotation motions at scales ≤1600au in 11 out of the 12 protostellar envelopes of our sample by measuring the velocity gradient along the equatorial axis, which we fit with a power-law model v∝rα. This suggests that coherent motions dominate the kinematics in the inner protostellar envelopes. The radial distributions of specific angular momentum in the CALYPSO sample suggest the following two distinct regimes within protostellar envelopes: the specific angular momentum decreases as j∝r1.6±0.2 down to ∼1600au and then tends to become relatively constant around ∼6x10–4(km/s).pc down to ∼50au.
Conclusions. The values of specific angular momentum measured in the inner Class 0 envelopes suggest that material directly involved in the star formation process (<1600 au) has a specific angular momentum on the same order of magnitude as what is inferred in small T-Tauri disks. Thus, disk formation appears to be a direct consequence of angular momentum conservation during the collapse. Our analysis reveals a dispersion of the directions of velocity gradients at envelope scales >1600 au, suggesting that these gradients may not be directly related to rotational motions of the envelopes. We conclude that the specific angular momentum observed at these scales could find its origin in other mechanisms, such as core-forming motions (infall, turbulence), or trace an imprint of the initial conditions for the formation of protostellar cores.

Abstract Copyright: © M. Gaudel et al. 2020

Journal keyword(s): stars: formation - stars: protostars - ISM: kinematics and dynamics - radio lines: ISM

Status at CDS : Examining the need for a new acronym.

Simbad objects: 31

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Number of rows : 31
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 LDN 1448 DNe 03 22.5 +30 35           ~ 507 0
2 IRAS 03222+3034 Y*O 03 25 22.32 +30 45 13.9           ~ 141 0
3 SSTc2d J032536.4+304522 Y*O 03 25 36.49 +30 45 22.2           ~ 193 1
4 IRAS 03225+3034 IR 03 25 36.49 +30 45 22.2           ~ 158 1
5 IRAS F03226+3033 Y*O 03 25 38.83 +30 44 06.2           ~ 327 0
6 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 443 3
7 NAME HH 7-11 MMS 2 smm 03 29 03.056 +31 15 51.67           ~ 80 0
8 V* V512 Per Or* 03 29 03.7578170808 +31 16 03.947525688           M3.5 377 0
9 [JCC87] IRAS 4A2 Y*O 03 29 10.413 +31 13 32.20           ~ 115 1
10 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 696 1
11 [JCC87] IRAS 4A1 Y*O 03 29 10.510 +31 13 31.01           ~ 103 1
12 NGC 1333 OpC 03 29 11.3 +31 18 36           ~ 1409 1
13 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 592 0
14 [JCC87] IRAS 4B2 smm 03 29 12.8 +31 13 02           ~ 16 0
15 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1311 0
16 Barnard 211 DNe 04 17 35 +27 43.1           ~ 122 0
17 LDN 1495 DNe 04 18.1 +27 37           ~ 353 1
18 IRAS 04191+1523 Y*O 04 22 00.43944 +15 30 21.2148           ~ 196 0
19 [TOS2014] MMS-2 cor 04 28 38.89 +26 51 33.9           ~ 11 0
20 [TOS2014] MMS-1 cor 04 28 38.96 +26 51 35.0           ~ 10 0
21 LDN 1521F DNe 04 28 39.3 +26 51 43           ~ 198 1
22 LDN 1521 DNe 04 33.1 +26 06           ~ 59 0
23 LDN 1527 DNe 04 39 53 +25 45.0           ~ 608 0
24 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4261 0
25 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 832 0
26 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 1077 2
27 NAME Aql Region reg 18 31.1 -02 10           ~ 378 0
28 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 558 0
29 LDN 1082 DNe 20 51.1 +60 11           ~ 35 0
30 NAME [BM89] L1082C DNe 20 51 27.4 +60 19 00           ~ 33 0
31 NAME GF 9-2 * 20 51 30.1 +60 18 39           ~ 25 1

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2023.10.04-09:33:49

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