J/ApJ/862/L2 First detection of HCOOH in TW Hya disk with ALMA (Favre+, 2018)
First detection of the simplest organic acid in a protoplanetary disk.
Favre C., Fedele D., Semenov D., Parfenov S., Codella C., Ceccarelli C.,
Bergin E.A., Chapillon E., Testi L., Hersant F., Lefloch B., Fontani F.,
Blake G.A., Cleeves L.I., Qi C., Schwarz K.R., Taquet V.
<Astrophys. J., 862, L2 (2018)>
=2018ApJ...862L...2F 2018ApJ...862L...2F
ADC_Keywords: Molecular data; Interstellar medium; YSOs; Radio continuum
Keywords: astrochemistry; ISM: molecules; protoplanetary disks;
radio lines: ISM; stars: individual (TW Hya)
Abstract:
The formation of asteroids, comets, and planets occurs in the interior
of protoplanetary disks during the early phase of star formation.
Consequently, the chemical composition of the disk might shape the
properties of the emerging planetary system. In this context, it is
crucial to understand whether and what organic molecules are
synthesized in the disk. In this Letter, we report the first detection
of formic acid (HCOOH) toward the TW Hydrae protoplanetary disk. The
observations of the trans-HCOOH 6(1,6)-5(1,5) transition were
carried out at 129GHz with Atacama Large Millimeter/Submillimeter
Array (ALMA). We measured a disk-averaged gas-phase t-HCOOH column
density of ~(2-4)x1012cm-2, namely as large as that of methanol.
HCOOH is the first organic molecule containing two oxygen atoms
detected in a protoplanetary disk, a proof that organic chemistry is
very active, albeit difficult to observe, in these objects.
Specifically, this simplest acid stands as the basis for synthesis of
more complex carboxylic acids used by life on Earth.
Description:
The observations were performed toward TW Hya on 2016 May 31 and on
2016 June 1 with 39 antennas and baselines from 15.1m (6.5kλ)
up to 713.1m (310.0kλ) with an on-source time of about 39 min
with ALMA during Cycle 3.
The spectral setup consisted of (i) six spectral windows, each with
960 channels and a channel width used during the observations of
244.141kHz (about 0.6km/s) that covered about 1.4GHz between 129.538
and 132.405GHz, and (ii) one spectral window, centered at 130.973GHz,
of 2GHz bandwidth (128 channels each of 15.625MHz) for continuum
imaging.
Objects:
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RA (ICRS) DE Designation(s)
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11 01 51.91 -34 42 17.0 TW Hya = V* TW Hya
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
map.dat 122 1 Summary of the t-HCOOH channel map
map/* . 1 The t-HCOOH channel map in FITS format
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Description of file:
The channel maps cube fits file has been generated through the CASA
software. Please, note that the data has been centered in this file.
For any questions/comments please contact C. Favre at
.
See also:
J/A+A/566/L5 : C/2012 F6 (Lemmon) & C/2013 R1 (Lovejoy) sp. (Biver+, 2014)
J/A+A/605/A21 : H2CO production in HD 163296 (Carney+, 2017)
J/A+A/606/A125 : HD163296 DCO+, DCN and N2D+ data cubes (Salinas+, 2017)
Byte-by-byte Description of file: map.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Target name
8- 16 F9.5 deg RAdeg Right ascension (J2000)
18- 26 F9.5 deg DEdeg Declination (J2000)
28- 37 A10 pix Dim Dimension (NxxNyxNz)
39- 64 A26 --- Date UT date of observation
66- 76 E11.6 Hz b_Freq [1.29663e+11] Minimum rest frequency
78- 87 E10.5 Hz B_Freq [1.2968e+11] Maximum rest frequency
89- 94 I6 Hz dFreq [259523] Frequency interval
96-100 I5 byte Size [35575] Size of the file
102-122 A21 --- FileName Name of the FITS file in subdirectory map
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 01-Aug-2019