J/A+A/671/A82 T CrA polarization image (Rigliaco+, 2023)
Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS):
Characterization of the young star T CrA and its circumstellar environment.
Rigliaco E., Gratton R., Ceppi S., C.Ginski., Hogerheijde M., Benisty M.,
Birnstie T., Dima M., Facchini S., Garufi A., Bae J., Langlois M.,
Lodato G., Mamajek E., Manara C.F., Menard F., Ribas A., Zurlo A.
<Astron. Astrophys. 671, A82 (2023)>
=2023A&A...671A..82R 2023A&A...671A..82R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Polarization ; Infrared
Keywords: circumstellar matter - stars: pre-main sequence -
protoplanetary disks - ISM: individual object: T CrA -
ISM: jets and outflows
Abstract:
In recent years, a new hot-topic has emerged in the star and planet
formation field, namely, the interaction between the circumstellar
disk and its birth cloud. The birth environments of young stars leave
strong imprints on the star itself and their surroundings. In this
context, we present a detailed analysis of the rich circumstellar
environment around the young Herbig Ae/Be star T CrA.
Our aim is to understand the nature of the stellar system and the
extended circumstellar structures, as seen in scattered light images.
We conducted our analysis on the basis of a set of combined archival
data and new adaptive optics images at a high contrast and high
resolution.
The scattered light images reveal the presence of a complex
environment around T CrA, composed of a bright, forwardscattering rim
of the disk's surface that is seen at very high inclinations, along
with a dark lane of the disk midplane, bipolar outflows, and streamer
features that are likely tracing infalling material from the
surrounding birth cloud onto the disk. The analysis of the light curve
suggests that the star is a binary with a period of 29.6 years,
confirming previous assertions based on spectro-astrometry. The
comparison of the scattered light images with the ALMA continuum and
12CO (2-1) line emission shows that the disk is in Keplerian
rotation and the northern side of the outflowing material is receding,
while the southern side is approaching the observer. The overall
system lies on dierent geometrical planes. The orbit of the binary
star is perpendicular to the outflows and is seen edge on. The disk is
itself seen edge-on, with a position angle of ∼7°. The direction
of the outflows seen in scattered light is in agreement with the
direction of the more distant molecular hydrogen emission-line objects
(MHOs) associated with the star. Modeling of the spectral energy
distribution (SED) using a radiative transfer scheme is in good
agreement with the proposed configuration, as well as the
hydrodynamical simulation performed using a smoothed particle
hydrodynamics (SPH) code.
We find evidence of streamers of accreting material around T CrA.
These streamers connect the filament, along which T CrA is forming
along with the outer parts of the disk, suggesting that the strong
misalignment between the inner and outer disk is due to a change in
the direction of the angular momentum of the material accreting on the
disk during the late phase of star formation. This impacts the
accretion taking place in the components of the binary, favoring the
growth of the primary with respect the secondary, in contrast to the
case of aligned disks.
Description:
CrA was observed on 2021 June 6 with SPHERE/InfraRed Dual-band Imager
and Spectrograph (IRDIS), in the dual-beam polarimetric imaging mode
(DPI) in the broadband H filter with pupil tracking setting, as part
of the Disk Evolution Study Through Imaging of Nearby Young Stars
(DESTINYS, Ginski et al. (2020A&A...642A.119G 2020A&A...642A.119G, 2021ApJ...908L..25G 2021ApJ...908L..25G))
program.
Additional SPHERE observations of T CrA were acquired
in 2016 and 2018 with the ESO programs 097.C-0591(A) and
0101.C-0686(A) (P.I. Schmidt) in classical imaging mode, using a
classical Lyot coronagraph and the broadband H filter (BB_H).
Objects:
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RA (2000) DE Designation(s)
------------------------------------------------------------
19 01 58.79 -36 57 50.3 T CrA = 2MASS J19015878-3657498
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 115 1 Information of fits image
fits/* . 1 fits image
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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- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 11 F5.2 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 23 F4.1 arcsec DEs Declination (J2000)
25- 28 I4 Kibyte size Size of FITS file
30- 60 A31 --- FileName Name of FITS file, in subdirectory fits
62-115 A54 --- Title Title of the FITS file
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Acknowledgements:
Elisabetta Rigliaco, elisabetta.rigliaco(at)inaf.it
(End) Patricia Vannier [CDS] 17-Feb-2023