J/A+A/623/A140 HD169142 SPHERE images (Gratton+, 2019)
Blobs, spiral arms, and a possible planet around HD169142.
Gratton R., Ligi R., Sissa E., Desidera S., Mesa D., Bonnefoy M.,
Chauvin G., Cheetham A., Feldt M., Lagrange A.M., Langlois M., Meyer M.,
Vigan A., Boccaletti A., Janson M., Lazzoni C., Zurlo A., De Boer J.,
Henning T., D'Orazi V., Gluck L., Madec F., Jaquet M., Baudoz P.,
Fantinel D., Pavlov A., Wildi F.
<Astron. Astrophys. 623, A140 (2019)>
=2019A&A...623A.140G 2019A&A...623A.140G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple - Exoplanets
Keywords: star: individual: HD 169142 - techniques: high angular resolution -
planets and satellites: detection - protoplanetary disks
Abstract:
Young planets are expected to cause cavities, spirals, and kinematic
perturbations in protostellar disks that may be used to infer their
presence. However, a clear detection of still-forming planets embedded
within gas-rich disks is still rare.
HD169142 is a very young Herbig Ae-Be star surrounded by a
pre-transitional disk, composed of at least three rings. While claims
of sub-stellar objects around this star have been made previously,
follow-up studies remain inconclusive. The complex structure of this
disk is not yet well understood.
We used the high contrast imager SPHERE at ESO Very large Telescope to
obtain a sequence of high-resolution, high-contrast images of the
immediate surroundings of this star over about three years in the
wavelength range 0.95-2.25um. This enables a photometric and
astrometric analysis of the structures in the disk.
While we were unable to definitively confirm the previous claims of a
massive sub-stellar object at 0.1-0.15arcsec from the star, we found
both spirals and blobs within the disk. The spiral pattern may be
explained as due to the presence of a primary, a secondary, and a
tertiary arm excited by a planet of a few Jupiter masses lying along
the primary arm, likely in the cavities between the rings. The blobs
orbit the star consistently with Keplerian motion, allowing a
dynamical determination of the mass of the star. While most of these
blobs are located within the rings, we found that one of them lies in
the cavity between the rings, along the primary arm of the spiral
design.
This blob might be due to a planet that might also be responsible for
the spiral pattern observed within the rings and for the cavity
between the two rings. The planet itself is not detected at short
wavelengths, where we only see a dust cloud illuminated by stellar
light, but the planetary photosphere might be responsible for the
emission observed in the K1 and K2 bands. The mass of this putative
planet may be constrained using photometric and dynamical arguments.
While uncertainties are large, the mass should be between 1 and 4
Jupiter masses. The brightest blobs are found at the 1:2 resonance
with this putative planet.
Description:
Data were acquired with the SPHERE high-contrast imager (Beuzit et al.
2008, in Proc. SPIE, Vol. 7015, Adaptive Optics Systems, 70151B) at
the ESO VLT Unit Telescope 3 within the guaranteed time observations
used for the SHINE (SpHere INfrared survey for Exoplanets) survey
(Chauvin et al. 2017, in SF2A-2017: Proceedings of the Annual meeting
of the French Society of Astronomy and Astrophysics, ed. C. Reyle, P.
Di Matteo, F. Herpin, E. Lagadec, A. Lancon, Z. Meliani, & F. Royer,
331-335). Data acquired up to 2017 have been described in Ligi et
al. (2018MNRAS.473.1774L 2018MNRAS.473.1774L). Here we add new data acquired in 2018 and
study the system anew using different ways to combine different
images. In these observations, we used SPHERE with both the Integral
Field Spectrograph (IFS : Claudi et al., 2008, in Proc. SPIE, Vol.
7014, Ground-based and Airborne Instrumentation for Astronomy II,
70143E) and the Infra-Red Dual Imaging and Spectrograph (IRDIS: Dohlen
et al., 2008, in Proc. SPIE, Vol. 7014, Ground-based and Airborne
Instrumentation for Astronomy II, 70143L; Vigan et al.,
2010MNRAS.407...71V 2010MNRAS.407...71V) simultaneously.
Objects:
------------------------------------------------------
RA (2000) DE Designation(s)
------------------------------------------------------
18 24 29.78 -29 46 49.3 HD169142 = EM* MWC 925
------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 125 6 Basic data for the FITS files
fits/* . 6 Individual fits files
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Star designation
10- 19 F10.6 deg RAdeg Right ascension (J2000.0)
21- 30 F10.6 deg DEdeg Declination (J2000.0)
32- 35 F4.2 mas/pix Scale Scale of the image
37- 39 I3 pix RApix Pixel along RA direction
41- 43 I3 pix DEpix Pixel along Dec direction
45- 51 F7.5 um blambda Minimum wavelength
53- 59 F7.5 um Blambda Maximum wavelength
61- 87 A27 --- Filename Name of FITS file, in subdirectory fits
89-116 A28 --- Title Title of the FITS file
118-125 F8.2 d JD Julian date (JD-2400000)
--------------------------------------------------------------------------------
Acknowledgements:
Raffaele Gratton, raffaele.gratton(at)inaf.it
(End) Patricia Vannier [CDS] 18-Mar-2019