J/A+A/642/L7 IRAS 04302+2247 CO, CS, CN, H2CO, CH3OH maps (Podio+, 2020)
ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT). II.
Vertical stratification of CO, CS, CN, H2CO, and CH3OH in a Class I disk.
Podio L., Garufi A., Codella C., Fedele D., Bianchi E., Bacciotti F.,
Ceccarelli C., Favre C., Mercimek S., Rygl K., Testi L.
<Astron. Astrophys. 642, L7 (2020)>
=2020A&A...642L...7P 2020A&A...642L...7P (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; YSOs ; Molecular data ; Radio lines
Keywords: protoplanetary disks - astrochemistry - ISM: molecules -
stars: individual: IRAS 04302+2247
Abstract:
The chemical composition of planets is inherited from that of the
natal protoplanetary disk at the time of planet formation. Increasing
observational evidence suggests that planet formation occurs in less
than 1-2Myr. This motivates the need for spatially resolved
spectral observations of young Class I disks, as carried out by the
ALMA chemical survey of Disk-Outflow sources in Taurus (ALMA-DOT). In
the context of ALMA-DOT, we observe the edge-on disk around the Class
I source IRAS 04302+2247 (the butterfly star) in the 1.3mm continuum
and five molecular lines. We report the first tentative detection of
methanol (CH3OH) in a Class I disk and resolve, for the first time,
the vertical structure of a disk with multiple molecular tracers. The
bulk of the emission in the CO 2-1, CS 5-4, and o-H2CO
31,2-21,1 lines originates from the warm molecular layer, with
the line intensity peaking at increasing disk heights, z, for
increasing radial distances, r. Molecular emission is vertically
stratified, with CO observed at larger disk heights (aperture
z/r∼0.41-0.45) compared to both CS and H2CO, which are nearly
cospatial (z/r∼0.21-0.28). In the outer midplane, the line emission
decreases due to molecular freeze-out onto dust grains (freeze-out
layer) by a factor of >100 (CO) and 15 (CS). The H2CO emission
decreases by a factor of only about 2, which is possibly due to H2CO
formation on icy grains, followed by a nonthermal release into the gas
phase. The inferred [CH3OH]/[H2CO] abundance ratio is 0.5-0.6,
which is 1-2 orders of magnitude lower than for Class 0 hot corinos,
and a factor ∼2.5 lower than the only other value inferred for a
protoplanetary disk (in TW Hya, 1.3-1.7). Additionally, it is at the
lower edge but still consistent with the values in comets. This may
indicate that some chemical reprocessing occurs in disks before the
formation of planets and comets.
Description:
The fits files contain the moment 0 maps shown in Figure 1 and 3 of
the letter.
The line intensity is in units of Jy/beam km/s.
Moment 0 maps were produced over the velocity range [+1.2, +10] km/s,
except for CO ([-3, +14.2] km/s)
The data are from the ALMA project 2018.1.01037.S (PI: L. Podio).
Objects:
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RA (2000) DE Designation(s)
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04 33 16.50 +22 53 20.4 IRAS 04302+2247 = NAME Butterfly Star
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 103 5 List of fits images
fits/* . 5 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 52 A23 "datime" Obs.date Observation date
54- 60 F7.3 GHz Freq Observed frequency
62- 66 I5 Kibyte size Size of FITS file
68- 82 A15 --- FileName Name of FITS file, in subdirectory fits
84-103 A20 --- Title Title of the FITS file
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Acknowledgements:
Linda Podio, lpodio(at)arcetri.inaf.it
(End) Patricia Vannier [CDS] 02-Sep-2020