J/AJ/160/221 Predicted planetary yields of gap transitional disks (Close, 2020)
The Separation and Hα contrasts of massive accreting planets in the gaps
of transitional disks: predicted Hα protoplanet yields for adaptive optics
surveys.
Close L.M.
<Astron. J., 160, 221 (2020)>
=2020AJ....160..221C 2020AJ....160..221C
ADC_Keywords: Exoplanets; Photometry, H-alpha; Stars, masses
Keywords: Planetary system formation ; Planet formation ; Protoplanetary disks ;
Stellar accretion disks ; Exoplanet detection methods ;
Direct imaging ; Circumstellar disks ; Stellar accretion ; Accretion ;
Adaptive interferometry ; Laser guide stars ; Coronagraphic imaging
Abstract:
We present a massive accreting gap planet model that ensures large
gaps in transitional disks are kept dust free by the scattering action
of three coplanar quasi-circular planets in a 1:2:4 mean motion
resonance (MMR). This model uses the constraint of the observed gap
size, and the dust-free nature of the gap, to determine within ∼10%
the possible orbits for three massive planets in an MMR. Calculated
orbits are consistent with the observed orbits and Hα emission
(the brightest line to observe these planets) for LkCa15b, PDS70b, and
PDS70c within observational errors. Moreover, the model suggests that
the scarcity of detected Hα planets is likely a selection effect
of the current limitations of non-coronagraphic, low (<10%) Strehl,
Hα imaging with adaptive optics (AO) systems used in past
Hα surveys. We predict that as higher Strehl AO systems (with
high- performance custom coronagraphs; like the 6.5m Magellan
Telescope MagAO-X system) are utilized at Hα, the number of
detected gap planets will substantially increase by more than tenfold.
For example, we show that >25±5 new Hα "gap planets" are
potentially discoverable by a survey of the best 19 transitional disks
with MagAO-X. Detections of these accreting protoplanets will
significantly improve our understanding of planet formation, planet
growth and accretion, solar system architectures, and planet-disk
interactions.
Description:
We made deep images with spatial resolutions of 20-25mas from the
ground at Hα. Previously, with the first large ≥6.5m visible
Adaptative Optic (AO) system (MagAO), we achieved contrasts of 10-3 at
0.2" from a bright star as we detected the in-fall of hydrogen gas as
it accreted onto low-mass companions in the cleared gaps of
transitional disks. All of these detections were made possible by the
spectral differential imaging (SDI) technique where an Hα image
has a scaled continuum image subtracted from it to remove some of the
PSF speckles and reveal any Hα planets.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 56 23 A list of the observed parameters of the large gap
transitional disks
table3.dat 83 23 The predicted planetary parameters from the MAG
model of gap planets
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See also:
J/ApJS/179/451 : Predicted IR excesses for protoplanetary disks (Kenyon+, 2008)
J/A+A/548/A56 : X-shooter spectra of 12 young stellar objects (Rigliaco+,2012)
J/ApJ/869/L41 : DSHARP I. Sample, ALMA obs. log and overview (Andrews+, 2018)
J/A+A/622/A156 : A search for accreting young companions (Cugno+, 2019)
J/A+A/632/A25 : PDS70 VLT/SPHERE images (Mesa+, 2019)
J/ApJ/880/49 : Predictions of giant exoplanet host star's (Hinkel+, 2019)
J/A+A/639/A121 : LkCa 15 & 2MASS J16100501-2132318 ALMa images (Facchini+,2020)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Transitional disk system name
12 A1 --- f_logMdot Approximate flag on logMdot
14- 19 F6.2 [Msun/yr] logMdot [-10.5/-6.8] log stellar accretion rate
21- 23 F3.1 Rjup Radp [1.3/1.8] Planet radius from COND models
25- 28 F4.2 mag AR [0/2.9] R band extinction towards the star
30- 34 F5.2 mag Rmag [6.5/13.1] SIMBAD apparent R band magnitude
36- 38 I3 pc Dist [104/400] Distance
40- 42 I3 AU Rcav [25/156] Cavity edge
44- 47 F4.2 solMass Mass [0.39/2.56] Stellar mass
49- 52 F4.1 solLum Lum [0.2/65.1] Stellar luminosity
54 A1 --- f_i Approximate flag on i
55- 56 I2 --- i [0/80] Approximate inclination from FVDM
images
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Transitional disk system name
11 A1 --- f_Name Flag on Name (1)
13- 17 F5.2 AU a1 [7.47/46.7] First gap orbital semi-major axis
19- 23 F5.2 AU a2 [11.8/74] Second gap orbital semi-major axis
25- 30 F6.2 AU a3 [18.8/117.5] Third gap orbital semi-major axis
32- 35 F4.2 arcsec Sep1 [0.03/0.26] First gap average projected on-sky
separation (2)
37- 40 F4.2 arcsec Sep2 [0.05/0.41] Second gap average projected on-sky
separation (2)
42- 45 F4.2 arcsec Sep3 [0.07/0.66] Third gap average projected on-sky
separation (2)
47- 51 F5.2 mag DelHa1 [4.88/12.3] First gap planet/star contrast
at ΔHα (3)
53- 57 F5.2 mag DelHa2 [5.39/13.5] Second gap planet/star contrast
at ΔHα (3)
59 A1 --- f_DelHa2 Flag on DelHa2 (4)
61- 65 F5.2 mag DelHa3 [5.89/14] Third gap planet/star contrast
at ΔHα (3)
67 A1 --- f_DelHa3 Flag on DelHa3 (4)
69- 73 F5.2 Mjup Mass1 [1.56/10.2] First gap planet predicted mass (3)
75- 78 F4.2 Mjup Mass2 [0.78/5.12] Second gap planet predicted mass (3)
80- 83 F4.2 Mjup Mass3 [0.39/2.56] Third gap planet predicted mass (3)
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Note (1): Flag as follows:
+ = faint Rmag>12mag AO targets have had their contrasts increased by +2mag
so they can be compared to the AO (5 occurrences)
Note (2): We note that this is simply an average position, the true position on
the sky depens on the unknown orbital phase and so these sep values
can underestimate the true sep by
(a/πD)(π-2)(1-cos(inclination)) and overestimate by
(a/D)[cos(inclination)-(1+((2-π)/π)(1-cos(inclination))]arcsec.
Note (3): Assuming Mp1=2Mp2 and Mp2=2Mp3. The ΔHα contrasts could
have errors of up to 1.0mag to -0.6mag and ΔHα
contrasts could have errors of +0.5mag to -0.3mag if the mass
ratios vary from 1.4x to 3x instead of 2x.
Note (4): Flag as follows:
b = Values have been calculated with equation 9. All others were
calculated with equation 8. (4 occurrences for DelHa2, 5
occurrences for DelHa3
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 22-Jan-2021