J/A+A/643/A99 DoAr 44 ugri light curves (Bouvier+, 2020)
Investigating the magnetospheric accretion process in the young pre-transitional
disk system DoAr 44 (V2062 Oph). A multiwavelength interferometric,
spectropolarimetric, and photometric observing campaign
Bouvier J., Alecian E., Alencar S., Sousa A., Donati J.-F., Perraut K.,
Bayo A., Rebull L.M., Dougados C., Duvert G., Berger J.-P., Benisty M.,
Pouilly K., Folsom C., Moutou C.
<Astron. Astrophys. 643, A99 (2020)>
=2020A&A...643A..99B 2020A&A...643A..99B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, pre-main sequence ; Photometry, SDSS
Keywords: stars: pre-main sequence - stars: variables: T Tauri, Herbig Ae/Be -
stars: magnetic field - stars: formation - accretion, accretion disks
Abstract:
Young stars interact with their accretion disk through their strong
magnetosphere.
We aim to investigate the magnetospheric accretion/ejection process in
the young stellar system DoAr 44 (V2062 Oph).
We monitored the system over several rotational cycles, combining
high-resolution spectropolarimetry at both optical and near-IR
wavelengths with long-baseline near-IR inteferometry and multicolor
photometry.
We derive a rotational period of 2.96d from the system's light curve,
which is dominated by stellar spots. We fully characterize the central
star's properties from the high signal-to-noise, high-resolution
optical spectra we obtained during the campaign. DoAr 44 is a young
1.2M☉ star, moderately accreting from its disk
(Macc=6.510-9M☉/yr), and seen at a low inclination
(i~=30°). Several optical and near-IR line profiles probing the
accretion funnel flows (Hα, Hβ, HeI 1083nm, Paβ) and
the accretion shock (HeI 587.6nm) are modulated at the stellar
rotation period. The most variable line profile is HeI 1083nm, which
exhibits modulated redshifted wings that are a signature of accretion
funnel flows, as well as deep blueshifted absorptions indicative of
transient outflows. The Zeeman-Doppler analysis suggests the star
hosts a mainly dipolar magnetic field, inclined by about 20° onto
the spin axis, with an intensity reaching about 800G at the
photosphere, and up to 2±0.8kG close to the accretion shock. The
magnetic field appears strong enough to disrupt the inner disk close
to the corotation radius, at a distance of about 4.6R* (0.043au),
which is consistent with the 5R* (0.047au) upper limit we derived for
the size of the magnetosphere in our Paper I from long baseline
interferometry.
DoAr 44 is a pre-transitional disk system, exhibiting a 25-30au gap
in its circumstellar disk, with the inner and outer disks being
misaligned. On a scale of 0.1au or less, our results indicate that
the system is steadily accreting from its inner disk through its
tilted dipolar magnetosphere. We conclude that in spite of a highly
structured disk on the large scale, perhaps the signature of ongoing
planetary formation, the magnetospheric accretion process proceeds
unimpeded at the star-disk interaction level.
Description:
Photometric observations were obtained at the Las Cumbres Observatory
Global Network (LCOGT) with the1m Sinistro telescopes from June 4 to
June 24, 2019. We usedSDSS/PanSTARRS u'g'r'i' filters with
exposure times of 60,30, 10, and 5s, respectively. A total of 219
images centered on DoAr 44 were obtained over 20 days with a cadence of
nearly three photometric sequences per 24 hours.
The table presents photometry of the DoAr 44 system.
Objects:
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RA (2000) DE Designation(s)
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16 31 33.46 -24 27 37.2 DoAr 44 = Haro 1-16
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 37 219 LCOGT u'g'r'i' differential photometry
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.8 d JD Julian date (JD-2450000)
15- 19 F5.2 mag dmag Differential magnitude between DoAr 44 and
the comparison star
21- 25 F5.2 mag dmagc Differential magnitude between the comparison
star and the check star
27- 28 A2 --- Filt [up gp rp ip] Filter
30- 33 F4.2 --- Airmass Airmass
35- 37 I3 deg DistM Moon distance from the target
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Acknowledgements:
Jerome Bouvier, jerome.bouvier(at)univ-grenoble-alpes.fr
(End) Patricia Vannier [CDS] 29-Sep-2020