J/A+A/609/A96 TROY project. I. (Lillo-Box+, 2018)
The TROY project: Searching for co-orbital bodies to known planets.
I. Project goals and first results from archival radial velocity.
Lillo-Box J., Barrado D., Figueira P., Leleu A., Santos N.C.,
Correia A.C.M., Robutel P., Faria J.P.
<Astron. Astrophys. 609, A96 (2018)>
=2018A&A...609A..96L 2018A&A...609A..96L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Planets ; Radial velocities ; Models
Keywords: planets and satellites: gaseous planets -
planets and satellites: formation -
minor planets, asteroids: general - techniques: radial velocities
Abstract:
The detection of Earth-like planets, exocomets or Kuiper belts show
that the different components found in the solar system should also be
present in other planetary systems. Trojans are one of these
components and can be considered fossils of the first stages in the
life of planetary systems. Their detection in extrasolar systems would
open a new scientific window to investigate formation and migration
processes. In this context, the main goal of the TROY project is to
detect exotrojans for the first time and to measure their occurrence
rate (eta-Trojan). In this first paper, we describe the goals and
methodology of the project. Additionally, we used archival radial
velocity data of 46 planetary systems to place upper limits on the
mass of possible trojans and investigate the presence of co-orbital
planets down to several tens of Earth masses. We used archival radial
velocity data of 46 close-in (P<5-days) transiting planets (without
detected companions) with information from high-precision radial
velocity instruments. We took advantage of the time of mid-transit and
secondary eclipses (when available) to constrain the possible presence
of additional objects co-orbiting the star along with the planet.
This, together with a good phase coverage, breaks the degeneracy
between a trojan planet signature and signals coming from additional
planets or underestimated eccentricity. We identify nine systems for
which the archival data provide >1-sigma evidence for a mass imbalance
between L4 and L5. Two of these systems provide >2σ detection,
but no significant detection is found among our sample. We also report
upper limits to the masses at L4/L5 in all studied systems and discuss
the results in the context of previous findings.
Description:
tablea4.dat: Posterior confidence intervals of the parameters
explored to fit the radial velocity data according to equation 9 in
the paper.
tablea6.dat: Maximum mass of possible trojan bodies for the six
tested models assuming their presence. We present the 95% confidence
intervals of the mass computed from random samplings of the radial
velocity semi-amplitude K2, the inclination i, the eccentricity e
(when applicable), and the stellar mass obtained from the literature.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea4.dat 192 46 *Derived parameters for the 46 planetary systems
analyzed and the nine models tested.
tablea6.dat 76 46 *Maximum mass of possible trojan bodies for the
six tested models assuming their presence.
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Note on tablea4.dat: Hyperparameters of the Gaussian process kernel, radial
velocity offsets, and jitter are not included here.
Note on tablea6.dat: We present the 99.7% confidence intervals of the mass
computed from random samplings of the radial velocity semi-amplitude K2,
the inclination i, the eccentricity e (when applicable), and the stellar
mass obtained from the literature.
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Object Planetary system
16- 23 F8.4 km/s Vsys Systemic velocity γ
24 A1 --- --- [+]
25- 30 F6.4 km/s E_Vsys Error on Vsys (upper value)
31 A1 --- --- [-]
32- 37 F6.4 km/s e_Vsys Error on Vsys (lower value)
39- 49 F11.9 d Per Orbital period of the planet
50 A1 --- --- [+]
51- 61 F11.9 d E_Per Error on Per (upper value)
62 A1 --- --- [-]
63- 73 F11.9 d e_Per Error on Per (lower value)
74- 85 F12.6 d T0 Time of planet transit (BJD-2400000)
86 A1 --- --- [+]
87- 94 F8.6 d E_T0 Error on T0 (upper value)
96 A1 --- --- [-]
97-104 F8.6 d e_T0 Error on T0 (lower value)
106-112 F7.2 m/s K Radial velocity semi-amplitude
113 A1 --- --- [+]
114-119 F6.2 m/s E_K Error on K (upper value)
120 A1 --- --- [-]
121-126 F6.2 m/s e_K Error on K (lower value)
128-134 F7.4 --- alpha New parameter defined in paper (Eq. 10) (G1)
135 A1 --- --- [+]
136-141 F6.4 --- E_alpha Error on alpha (upper value)
142 A1 --- --- [-]
143-148 F6.4 --- e_alpha Error on alpha (lower value)
150-156 F7.4 --- c Parameter defined in paper (see Eq. 19
in Leleu et al., 2017A&A...599L...7L 2017A&A...599L...7L) (2)
157 A1 --- --- [+]
158-163 F6.4 --- E_c Error on c (upper value)
164 A1 --- --- [-]
165-170 F6.4 --- e_c Error on c (lower value)
172-178 F7.4 --- d Parameter defined in paper (see Eq. 19
in Leleu et al., 2017A&A...599L...7L 2017A&A...599L...7L) (2)
179 A1 --- --- [+]
180-185 F6.4 --- E_d Error on d (upper value)
186 A1 --- --- [-]
187-192 F6.4 --- e_d Error on d (lower value)
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Note (2): Parameters definitions:
c = k1 + O{ ε2, ek2, ε*ek }
d = h1 + O{ ε2, ek2, ε*ek }
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Byte-by-byte Description of file: tablea6.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Object Planetary system
16- 22 F7.4 --- alpha New parameter defined in paper (Eq. 10) (G1)
23 A1 --- --- [+]
24- 29 F6.4 --- E_alpha Error on alpha (upper value)
30 A1 --- --- [-]
31- 36 F6.4 --- e_alpha Error on alpha (lower value)
38- 43 F6.2 Mgeo mt Derived trojan mass (1)
44 A1 --- --- [+]
45- 49 F5.1 Mgeo E_mt Error om mt (upper value)
50 A1 --- --- [-]
51- 55 F5.1 Mgeo e_mt Error on mt (lower value)
57 A1 --- l_mL4 Limit flag on mL4
58- 64 F7.1 Mgeo mL4 Upper mass limit in L4
66 A1 --- l_mL5 Limit flag on mL5
67- 72 F6.1 Mgeo mL5 Upper mass limit in L5
74- 76 F3.1 --- alphasnr Significance of alpha detection
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Note (1): Estimation of the trojan mass based on α and assuming small
eccentricity, mt≪mp, and trojan location around one the two stable
Lagrangian points.
Negative values correspond to L4 and positive values correspond to L5.
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Global notes:
Note (G1):
alpha = -(m2/m1)sinζ + O{(m2/m1)2, ek2, (m2/m1)*ek}
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Acknowledgements:
Jorge Lillo-Box, jlillobo(at)eso.org
(End) Patricia Vannier [CDS] 09-Nov-2017