J/A+A/641/A33 EX Lup SPHERE and SINFONI images (Rigliaco+, 2020)
The circumstellar environment of EX Lup: the SPHERE and SINFONI views.
Rigliaco E., Gratton R., Kospal A., Mesa D., D'Orazi V., Abraham P.,
Desidera S., Ginski C., van Holstein R.G., Dominik C., Garufi A.,
Henning T., Menard F., Zurlo A., Baruolo A., Maurel D., Blanchard P.,
Weber L.
<Astron. Astrophys. 641, A33 (2020)>
=2020A&A...641A..33R 2020A&A...641A..33R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Polarization ; Spectra, infrared
Keywords: stars: individual: EX Lup - stars: formation - protoplanetary disks -
circumstellar matter - techniques: polarimetric -
stars: pre-main sequence
Abstract:
EX Lup is a well-studied T Tauri star that represents the prototype of
young eruptive stars EXors. These are characterized by repetitive
outbursts due to enhanced accretion from the circumstellar disk onto
the star. In this paper we analyze new adaptive optics imaging and
spectroscopic observations to study EX Lup and its circumstellar
environment in near-infrared in its quiescent phase.
We aim at providing a comprehensive understanding of the circumstellar
environment around EX Lup in quiescence that builds upon the vast
literature data.
We observed EX Lup in quiescence with the high contrast imager
SPHERE/IRDIS in the dual-beam polarimetric imaging mode to resolve the
circumstellar environment in near-infrared scattered light. We
complemented these data with earlier SINFONI spectroscopy, also taken
in quiescence.
Results.We resolve for the first time in scattered light a compact
feature around EX Lup azimuthally extending from ∼280° to
∼360°, and radially extending from 0.3" to 0.55" in the plane of
the disk. We explore two different scenarios for the detected emission.
The first one accounts for the emission as coming from the brightened
walls of the cavity excavated by the outflow whose presence was
suggested by ALMA observations in the J=3-2 line of 12CO. The second
one accounts for the emission as coming from an inclined disk. In this
latter case we detect for the first time a more extended circumstellar
disk in scattered light, which shows that a region between 10 and 30au
is depleted of um-size grains. We compare the J-, H- and K- band
spectra obtained with SINFONI in quiescence with the spectra taken
during the outburst, showing that all the emission lines were due to
the episodic accretion event.
Based on the morphology analysis we favour the scenario in which the
scattered light is coming from a circumstellar disk rather than the
outflow around EX Lup. We analyze the origin of the observed feature
either as coming from a continuous circumstellar disk with a cavity,
or from the illuminated wall of the outer disk or from a shadowed
disk. Moreover, we discuss what is the origin of the m-size grains
depleted region, exploring the possibility that a sub-stellar
companion may be the cause of it.
Description:
EX Lup was observed with SPHERE (Spectro-Polarimetric
High-contrast Exoplanet REsearch) as part of the ongoing SPHERE
guaranteed time program to search for and characterize circumstellar
disks. Observations were carried out with the InfraRed Dual-band
Imager and Spectrograph (IRDIS) subsystem in dual-beam polarimetric
imaging mode (DPI) on May 16, 2017.
SPHERE/IRDIS H-band Qphi and Uphi images of EX Lup, as from the Fig. 1
of the paper. IRDIS was used in DPI mode in H-band, together with
NALCYJH_S coronagraph with Inner Working Angle (IWA) of 0.15".
SINFONI J-band continuum and Pabeta line images of EX Lup, as for Fig.
7 of the paper.
Objects:
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RA (2000) DE Designation(s)
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16 03 05.49 -40 18 25.4 EX Lup = HD 325367
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 122 4 List of fits files
fits/* . 4 Individual fits files
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See also:
J/A+A/507/881 : Emission lines in EX Lup optical spectrum (Sipos+, 2009)
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)
12 A1 --- DE- Declination sign (J2000)
13- 14 I2 deg DEd Declination (J2000)
16- 17 I2 arcmin DEm Declination (J2000)
19- 22 F4.1 arcsec DEs Declination (J2000)
24- 27 I4 --- Nx Number of pixels along X-axis
29- 32 I4 --- Ny Number of pixels along Y-axis
34- 37 I4 Kibyte size Size of FITS file
39- 81 A43 --- FileName Name of FITS file, in subdirectory fits
83-122 A40 --- Title Title of the FITS file
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Acknowledgements:
Elisabetta Rigliaco, elisabetta.rigliaco(at)inaf.it
(End) Patricia Vannier [CDS] 29-Jun-2020