J/A+A/682/A55 Sz 65 and Sz 66 ALMA observations (Miley+, 2024)
High-resolution ALMA observations of compact discs in the wide-binary system
Sz 65 and Sz 66.
Miley J.M., Carpenter J., Booth R., Jennings J., Haworth T.J., Vioque M.,
Andrews S., Wilner D., Benisty M., Huang J., Perez L., Guzman V.,
Ricci L., Isella A.
<Astron. Astrophys. 682, A55 (2024)>
=2024A&A...682A..55M 2024A&A...682A..55M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Carbon monoxide ; Radio sources
Keywords: planet-disk interactions - stars: pre-main sequence -
protoplanetary discs
Abstract:
Substructures in disc density are ubiquitous in the bright extended
discs that are observed with high resolution. These substructures are
intimately linked to the physical mechanisms driving planet formation
and disc evolution. Surveys of star-forming regions find that most
discs are in fact compact, less luminous, and do not exhibit these
same substructures. It remains unclear whether compact discs also have
similar substructures or if they are featureless. This suggests that
different planet formation and disc evolution mechanisms operate in
these discs.
We investigated evidence of substructure within two compact discs
around the stars Sz 65 and Sz 66 using high angular resolution
observations with ALMA at 1.3mm. The two stars form a wide-binary
system with 6.36" separation. The continuum observations achieve a
synthesised beam size of 0.026"x0.018", equivalent to about
4.0x2.8au, enabling a search for substructure on these spatial scales
and a characterisation of the gas and dust disc sizes with high
precision.
We analysed the data in the image plane through an analysis of
reconstructed images, as well as in the uv plane by non-parametrically
modelling the visibilities and by an analysis of the 12CO (2-1)
emission line. Comparisons were made with high-resolution observations
of compact discs and radially extended discs.
We find evidence of substructure in the dust distribution of Sz 65,
namely a shallow gap centred at ∼20au, with an emission ring exterior
to it at the outer edge of the disc. Ninety percent of the measured
continuum flux is found within 27au, and the distance for 12CO is
161au. The observations show that Sz 66 is very compact: 90% of the
flux is contained within 16 au, and 90% of the molecular gas flux lies
within 64au.
While the overall prevalence and diversity of substructure in compact
discs relative to larger discs is yet to be determined, we find
evidence that substructures can exist in compact discs
Description:
Reduced ALMA images of the continuum and CO emission.
Objects:
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RA (2000) DE Designation(s)
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15 39 27.77 -34 46 17.2 Sz65 = V* IK Lup
15 39 28.28 -34 46 18.0 Sz66 = TIC 8159415
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 183 2 List of fits files
fits/* . 2 Individual fits files
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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 datacube
33- 55 A23 "datime" Obs.date Observation date
57- 67 E11.6 Hz bFREQ Observed frequency or lower interval of
observed frequency
69- 78 E10.5 Hz BFREQ ? Upper interval of observed frequency
80- 85 I6 Hz dFREQ ? Frequency resolution
87- 92 I6 Kibyte size Size of FITS file
94-154 A61 --- FileName Name of FITS file, in subdirectory fits
156-183 A28 --- Title Title of the FITS file
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Acknowledgements:
James Miley, jmiley73(at)gmail.com
(End) Patricia Vannier [CDS] 18-Dec-2023