J/A+A/671/L2 Flybys in debris disk systems with Gaia eDR3 (Bertini+, 2023)
Flybys in debris disk systems with Gaia eDR3.
Bertini L., Roccatagliata V., Kim M.
<Astron. Astrophys. 671, L2 (2023)>
=2023A&A...671L...2B 2023A&A...671L...2B (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, distances ; Stars, masses
Keywords: protoplanetary disks - astrometry
Abstract:
Debris disks represent the last phase of the evolution of
protoplanetary disks around young stellar objects where planetary
systems had most likely already been formed. Resolved systems show
peculiar structures, such as asymmetries or spirals, which may be
associated with either the presence of a low-mass companion or
dynamical interactions with a perturber during a flyby event.
We aim to observationally and statistically constrain the influence of
flybys in the formation and evolution of debris disks. Methods. We
compiled a sample of 254 debris disks with ages between 2Myr and 8Gyr
that are either part of an association or isolated, drawing the binary
and planetary companions of the systems mainly from the literature.
Using the Gaia eDR3 astrometric data and radial velocities of our
sample, as well as all the sources in a specific region of the sky, we
reconstructed the relative linear motions in the last 5Myr and made
predictions for the next 2Myr. Relating the Hill radius of each
debris disk system and the closest distances reached by the two
sources, we defined the flyby events in terms of position and time.
We find that in the period between the last 5Myrs and the next 2Myrs,
90% of the analyzed systems have experienced at least a close flyby,
while 7% of them have experienced flybys at distances greater than
0.5RHill. In particular, 75% of them have experienced at least one
past close encounter and 36% multiple past close encounters. From the
sub-sample of resolved debris disk (41 out of 94), 80% of the analyzed
systems experience at least an encounter within 0.8pc. From the
subsample of 10 debris disks with planets, half of these systems do
show misalignment between disk and planet, stirring, or asymmetries.
Systems with a misalignment between the planetary orbit and the disk
do indeed experience at least one flyby event. In particular, when the
planet orbits have a difference with the disk inclination higher than
about 20°, as in the case of HD 38529, we find that multiple close
encounters have taken place in the last 5Myr, as theoretically
predicted.
The high incidence of encounters, particularly close encounters,
experienced by the systems in the last 5Myr suggests the fundamental
impact of flybys on the evolution of debris disks. Moreover, despite
the low statistics, it is interesting to highlight that flybys that
have been theoretically predicted so far in peculiar resolved systems
have also been observationally constrained.
Description:
The catalogue of flybys in 118 debris disk systems is based on the
Gaia eDR3 astrometric data and radial velocities. It includes the
masses compiled from literature (Stassun et al., 2019AJ....158..138S 2019AJ....158..138S,
Cat. IV/38) and the computed Hill radius. Using the Gaia eDR3
astrometric data and radial velocities of the sample, as well as all
the sources in a specific region of the sky, we reconstructed the
relative linear motions in the last 5Myr and made predictions for the
next 2Myr. Relating the Hill radius of each debris disk system and the
closest distances reached by the two sources, we defined the flyby
events in terms of position and time with uncertainties.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 32 117 Masses and computed Hill radii of the 118 stars
in the sample with Gaia DR2 radial velocity
tablea1.dat 126 1153 Flyby distances and flyby times of the stars
which show at least one flyby
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See also:
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Simbad name of the star
14- 18 F5.3 Msun Mass Mass of the star (taken from Stassun et al.,
2019AJ....158..138S 2019AJ....158..138S, Cat. IV/38)
21- 26 F6.4 pc HillRad Hill radius
28- 32 F5.3 pc e_HillRad Error on the Hill radius
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Assoc Name of the association (1)
24- 52 A29 --- Name Simbad name of the main star
54- 82 A29 --- Flyby Name of the perturber
84 A1 --- Close [Y/N] Flyby is a close encounter? (Y or N) (2)
86 A1 --- IRexcess [Y/N] Perturber with far infrared excess
(Y or N) (2)
88- 91 F4.2 pc Rmin Flyby distance
94-100 F7.3 pc E_Rmin Upper error on the flyby distance
103-107 F5.3 pc e_Rmin Lower error on the flyby distance
109-113 F5.2 Myr tflyby Flyby time (+ past flybys, - future flybys)
116-119 F4.2 Myr E_tflyby Upper error on the flyby time
122-126 F5.3 Myr e_tflyby Lower error on the flyby time
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Note (1): For the Not associated main stars, we highlight the 5 different fields
which cover defined ranges in galactic latitude, galactic longitude and
parallax, as follow.
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Name Latitude [deg] Longitude [deg] Parallax [mas]
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Field 0 -70/20 90/170 3.0/ 10
Field 1 -90/ 0 0/180 7.4/100
Field 2 0/90 0/180 7.4/100
Field 3 -90/ 0 180/360 7.4/300
Field 4 0/90 180/360 7.4/100
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Note (2): Close encounters are highlighted as well as if the perturber shows a
FIR excess in its spectral energy distribution.
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Acknowledgements:
From Veronica Roccatagliata, veronica.roccatagliata(at)unipi.it
(End) Patricia Vannier [CDS] 23-Feb-2023