J/A+A/645/A139 ALMA mm observations of VLMS in Taurus (Kurtovic+, 2021)
Size and structures of disks around very low mass stars in the
Taurus star-forming region.
Kurtovic N.T., Pinilla P., Long F., Benisty M., Manara C.F., Natta A.,
Pascucci I., Ricci L., Scholz A., Testi L.
<Astron. Astrophys. 645, A139 (2021)>
=2021A&A...645A.139K 2021A&A...645A.139K (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Interferometry
Keywords: accretion, accretion disk - circumstellar matter -
stars: pre-main sequence - protoplanetary disks -
planets and satellites: formation
Abstract:
The discovery of giant planets orbiting very low mass stars (VLMS) and
the recent observed substructures in disks around VLMS is challenging
planet formation models. Specifically, radial drift of dust particles
is a catastrophic barrier in these disks, which prevents the formation
of planetesimals and therefore planets.
We aim to estimate if structures, such as cavities, rings, and gaps,
are common in disks around VLMS and to test models of structure
formation in these disks. We also aim to compare the radial extent of
the gas and dust emission in disks around VLMS, which can give us
insight about radial drift.
We studied six disks around VLMS in the Taurus star-forming region
using ALMA Band 7 (∼340GHz) at a resolution of ∼0.1". The targets were
selected because of their high disk dust content in their stellar mass
regime.
Our observations resolve the disk dust continuum in all disks. In
addition, we detect the 12CO (J=3-2) emission line in all targets
and 13CO (J=3-2) in five of the six sources. The angular resolution
allows the detection of dust substructures in three out of the six
disks, which we studied by using UV-modeling. Central cavities are
observed in the disks around stars MHO6 (M5.0) and CIDA1 (M4.5), while
we have a tentative detection of a multi-ringed disk around J0433. We
estimate that a planet mass of 0.1MJup or 0.4MSaturn is required
for a single planet to create the first gap in J0433. For the cavities
of MHO6 and CIDA1, a Saturn-mass planet (0.3MJup) is required. The
other three disks with no observed structures are the most compact and
faintest in our sample, with the radius enclosing 90% of the continuum
emission varying between 13-21au. The emission of 12CO and 13CO is
more extended than the dust continuum emission in all disks of our
sample. When using the 12CO emission to determine the gas disk
extension Rgas, the ratio of Rgas/Rdust in our sample varies from 2.3
to 6.0. One of the disks in our sample, CIDA7, has the largest
Rgas/Rdust ratio observed so far, which is consistent with models of
radial drift being very efficient around VLMS in the absence of
substructures.
Given our limited angular resolution, substructures were only directly
detected in the most extended disks, which represent 50% of our
sample, and there are hints of unresolved structured emission in one
of the bright smooth sources. Our observations do not exclude giant
planet formation on the substructures observed. A comparison of the
size and luminosity of VLMS disks with their counterparts around
higher mass stars shows that they follow a similar relation .
Description:
Interferometric millimeter observations of disks around very low mass
stars in the Taurus star-forming region. The six disks were observed
with ALMA Band 7, and different antenna configurations have been
combined to produce the datasets. Original observations contained dust
continuum emission, and the molecular lines 12CO J:3-2 and 13CO
J:3-2.
ADS/JAO.ALMA#2012.1.00743.S: ALMA Project containing MHO6, J0433, J0420
ADS/JAO.ALMA#2015.1.00934.S: ALMA Project containing CIDA1
ADS/JAO.ALMA#2016.1.01511.S: ALMA Project containing CIDA1, J0415
ADS/JAO.ALMA#2018.1.00310.S:
ALMA Project containing MHO6, J0433, CIDA7, J0420, J0415
Objects:
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RA (ICRS) DE Designation(s)
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04 14 17.620 +28 06 09.289 CIDA1 = 2MASS J04141760+2806096
04 42 21.022 +25 20 33.996 CIDA7 = 2MASS J04422101+2520343
04 15 58.016 +27 46 16.811 J0415 = 2MASS J04155799+2746175
04 20 25.581 +27 00 35.242 J0420 = 2MASS J04202555+2700355
04 33 44.670 +26 15 00.080 J0433 = 2MASS J04334465+2615005
04 32 22.128 +18 27 42.286 MHO6 = 2MASS J04322210+1827426
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 142 18 List of fits images and datacubes
fits/* . 18 Individual fits images and datacubes
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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- 31 I2 --- Nz ? Number of slices for the datacubes
33- 58 A26 "datime" Obs.date Observation date
60- 66 F7.3 GHz Freq Observed frequency or lower value of
frequency interval for the datacubes
68- 74 F7.3 GHz BFreq ? Upper value of frequency interval
for the datacubes
76- 86 E11.6 Hz dFreq ? Frequency resolution for the datacubes
88- 93 I6 Kibyte size Size of FITS file
95-106 A12 --- FileName Name of FITS file, in subdirectory fits
108-142 A35 --- Title Title of the FITS file
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Acknowledgements:
Nicolas Kurtovic, kurtovic(at)mpia.de
References:
Pinilla et al., 2018A&A...615A..95P 2018A&A...615A..95P,
Resolved millimeter-dust continuum cavity around the very low mass young
star CIDA 1
(End) Patricia Vannier [CDS] 18-Jan-2021