2019A&A...623L...6P


Query : 2019A&A...623L...6P

2019A&A...623L...6P - Astronomy and Astrophysics, volume 623, L6-6 (2019/3-1)

Organic molecules in the protoplanetary disk of DG Tauri revealed by ALMA.

PODIO L., BACCIOTTI F., FEDELE D., FAVRE C., CODELLA C., RYGL K.L.J., KAMP I., GUIDI G., BIANCHI E., CECCARELLI C., COFFEY D., GARUFI A. and TESTI L.

Abstract (from CDS):


Context. Planets form in protoplanetary disks and inherit their chemical compositions.
Aims. It is thus crucial to map the distribution and investigate the formation of simple organics, such as formaldehyde and methanol, in protoplanetary disks.
Methods. We analyze ALMA observations of the nearby disk-jet system around the T Tauri star DG Tau in the o-H2CO 31,2-21,1 and CH3OH 3–2,2-4–1,4 E, 50,5-40,4 A transitions at an unprecedented resolution of ∼0.15", i.e., ∼18au at a distance of 121pc.
Results. The H2CO emission originates from a rotating ring extending from ∼40 au with a peak at ∼62au, i.e., at the edge of the 1.3mm dust continuum. CH3OH emission is not detected down to an rms of 3mJy/beam in the 0.162km/s channel. Assuming an ortho-to-para ratio of 1.8-2.8 the ring- and disk-height-averaged H2CO column density is ∼0.3-4x1014cm–2, while that of CH3OH is <0.04-0.7x1014cm–2. In the inner 40au no o-H2CO emission is detected with an upper limit on its beam-averaged column density of ∼0.5-6x1013cm–2.
Conclusions. The H2CO ring in the disk of DG Tau is located beyond the CO iceline (RCO∼30au). This suggests that the H2CO abundance is enhanced in the outer disk due to formation on grain surfaces by the hydrogenation of CO ice. The emission peak at the edge of the mm dust continuum may be due to enhanced desorption of H2CO in the gas phase caused by increased UV penetration and/or temperature inversion. The CH3OH/H2CO abundance ratio is <1, in agreement with disk chemistry models. The inner edge of the H2CO ring coincides with the radius where the polarization of the dust continuum changes orientation, hinting at a tight link between the H2CO chemistry and the dust properties in the outer disk and at the possible presence of substructures in the dust distribution.

Abstract Copyright: © ESO 2019

Journal keyword(s): protoplanetary disks - astrochemistry - ISM: molecules - stars: individual: DG Tau

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 QSO B0235+1624 BLL 02 38 38.93010450 +16 36 59.2745528   16.46 15.50 15.92   ~ 1531 2
2 V* DG Tau Or* 04 27 04.6921275888 +26 06 16.060169268 13.57 13.97 10.50 12.28   K6Ve 1020 1
3 V* DM Tau Or* 04 33 48.7336763736 +18 10 09.973460280 14.30 14.82 14.00     M2Ve 631 0
4 ICRF J043804.9+300445 QSO 04 38 04.94832264 +30 04 45.5179109       19.36   ~ 67 1
5 V* AB Aur Ae* 04 55 45.8458932216 +30 33 04.292077032 7.20 7.16 7.05 6.96 6.70 A0Ve 1060 2
6 QSO B0507+179 QSO 05 10 02.36912937 +18 00 41.5815635   20.0 19.0 19.09   ~ 423 1
7 V* V883 Ori Or* 05 38 18.1018261392 -07 02 26.017707120           F:I: 211 0
8 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 1878 1
9 IRAS 16245-2423 TT* 16 27 37.1906433768 -24 30 35.025246828       16.66 14.67 B5-F2 300 0
10 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A1Vep 1091 0

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