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See detailWASP-24 b: A New Transiting Close-in Hot Jupiter Orbiting a Late F-star
Street, R. A.; Simpson, E.; Barros, S. C. C. et al

in Astrophysical Journal (2010), 720

We report the discovery of a new transiting close-in giant planet, WASP-24 b, in a 2.341 day orbit, 0.037 AU from its F8-9 type host star. By matching the star's spectrum with theoretical models, we infer ... [more ▼]

We report the discovery of a new transiting close-in giant planet, WASP-24 b, in a 2.341 day orbit, 0.037 AU from its F8-9 type host star. By matching the star's spectrum with theoretical models, we infer an effective temperature T [SUB]eff[/SUB] = 6075 ± 100 K and a surface gravity of log g = 4.15 ± 0.10. A comparison of these parameters with theoretical isochrones and evolutionary mass tracks places only weak constraints on the age of the host star, which we estimate to be 3.8[SUP]+1.3[/SUP] [SUB]-1.2[/SUB] Gyr. The planetary nature of the companion was confirmed by radial velocity measurements and additional photometric observations. These data were fit simultaneously in order to determine the most probable parameter set for the system, from which we infer a planetary mass of 1.071[SUP]+0.036[/SUP] [SUB]-0.038[/SUB] M [SUB]Jup[/SUB] and radius 1.3[SUP]+0.039[/SUP] [SUB]-0.037[/SUB] R [SUB]Jup[/SUB]. [less ▲]

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See detailWASP-8b: a retrograde transiting planet in a multiple system
Queloz, D.; Anderson, D.; Collier Cameron, A. et al

in Astronomy and Astrophysics (2010), 517

We report the discovery of WASP-8b, a transiting planet of 2.25 ± 0.08 M[SUB]Jup[/SUB] on a strongly inclined eccentric 8.15-day orbit, moving in a retrograde direction to the rotation of its late-G host ... [more ▼]

We report the discovery of WASP-8b, a transiting planet of 2.25 ± 0.08 M[SUB]Jup[/SUB] on a strongly inclined eccentric 8.15-day orbit, moving in a retrograde direction to the rotation of its late-G host star. Evidence is found that the star is in a multiple stellar system with two other companions. The dynamical complexity of the system indicates that it may have experienced secular interactions such as the Kozai mechanism or a formation that differs from the “classical” disc-migration theory. Based on observations made with HARPS spectrograph on the 3.6-m ESO telescope and the EULER Swiss telescope at La Silla Observatory, Chile.Radial velocity data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/517/L1">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/517/L1</A> [less ▲]

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See detailH-band thermal emission from the 19-h period planet WASP-19b
Anderson, D. R.; Gillon, Michaël ULg; Maxted, P. F. L. et al

in Astronomy and Astrophysics (2010), 513

We present the first ground-based detection of thermal emission from an exoplanet in the H-band. Using HAWK-I on the VLT, we observed an occultation of WASP-19b by its G8V-type host star. WASP-19b is a ... [more ▼]

We present the first ground-based detection of thermal emission from an exoplanet in the H-band. Using HAWK-I on the VLT, we observed an occultation of WASP-19b by its G8V-type host star. WASP-19b is a Jupiter-mass planet with an orbital period of only 19 h, and thus, being highly irradiated, is expected to be hot. We measure an H-band occultation depth of 0.259[SUP]+0.046[/SUP][SUB]-0.044[/SUB]%, which corresponds to an H-band brightness temperature of T[SUB]H[/SUB] = 2580 ± 125 K. A cloud-free model of the planet's atmosphere, with no redistribution of energy from day-side to night-side, under predicts the planet/star flux density ratio by a factor of two. As the stellar parameters, and thus the level of planetary irradiation, are well-constrained by measurement, it is likely that our model of the planet's atmosphere is too simple. Based on data collected with the VLT/HAWKI instrument at ESO Paranal Observatory, Chile (programs 083.C-0377(A)).The photometric time-series used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/513/L3">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/513/L3</A> [less ▲]

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See detailWASP-26b: A 1-Jupiter-mass planet around an early-G-type star
Smalley, B.; Anderson, D. R.; Collier Cameron, A. et al

in Astronomy and Astrophysics (2010)

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-magnitude early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A ... [more ▼]

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-magnitude early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02 +/- 0.03 M_Jup and radius of 1.32 +/- 0.08 R_Jup. The host star, WASP-26, has a mass of 1.12 +/- 0.03 M_sun and a radius of 1.34 +/- 0.06 R_sun and is in a visual double with a fainter K-type star. The two stars are at least a common-proper motion pair with a common distance of around 250 +/- 15 pc and an age of 6 +/- 2 Gy. [less ▲]

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See detailWASP-17b: an ultra-low density planet in a probable retrograde orbit
Anderson, D. R.; Hellier, C.; Gillon, Michaël ULg et al

in Astrophysical Journal (2010), 709(1), 159-167

We report the discovery of the transiting giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses but 1.5-2 Jupiter radii, giving a density of 6-14 per cent that of Jupiter ... [more ▼]

We report the discovery of the transiting giant planet WASP-17b, the least-dense planet currently known. It is 1.6 Saturn masses but 1.5-2 Jupiter radii, giving a density of 6-14 per cent that of Jupiter. WASP-17b is in a 3.7-day orbit around a sub-solar metallicity, V = 11.6, F6 star. Preliminary detection of the Rossiter-McLaughlin effect suggests that WASP-17b is in a retrograde orbit (lambda ~ -150 deg), indicative of a violent history involving planet-planet or planet-star scattering. WASP-17b's bloated radius could be due to tidal heating resulting from recent or ongoing tidal circularisation of an eccentric orbit, such as the highly eccentric orbits that typically result from scattering interactions. It will thus be important to determine more precisely the current orbital eccentricity by further high-precision radial velocity measurements or by timing the secondary eclipse, both to reduce the uncertainty on the planet's radius and to test tidal-heating models. Owing to its low surface gravity, WASP-17b's atmosphere has the largest scale height of any known planet, making it a good target for transmission spectroscopy. [less ▲]

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See detailWASP-19b: The Shortest Period Transiting Exoplanet Yet Discovered
Hebb, L.; Collier-Cameron, A.; Triaud, A H M J et al

in Astrophysical Journal (2010), 708

We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass M [SUB]pl[/SUB] = 1.15 ± 0.08 M[SUB]J[/SUB] , radius R [SUB]pl[/SUB] = 1.31 ± 0.06 ... [more ▼]

We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass M [SUB]pl[/SUB] = 1.15 ± 0.08 M[SUB]J[/SUB] , radius R [SUB]pl[/SUB] = 1.31 ± 0.06 R[SUB]J[/SUB] , and orbital period P = 0.7888399 ± 0.0000008 days. Through spectroscopic analysis, we determine the host star to be a slightly super-solar metallicity ([M/H] = 0.1 ± 0.1 dex) G-dwarf with T [SUB]eff[/SUB] = 5500 ± 100 K. In addition, we detect periodic, sinusoidal flux variations in the light curve which are used to derive a rotation period for the star of P [SUB]rot[/SUB] = 10.5 ± 0.2 days. The relatively short stellar rotation period suggests that either WASP-19 is somewhat young (~ 600 Myr old) or tidal interactions between the two bodies have caused the planet to spiral inward over its lifetime resulting in the spin-up of the star. Due to the detection of the rotation period, this system has the potential to place strong constraints on the stellar tidal quality factor, Q'[SUB] s [/SUB], if a more precise age is determined. [less ▲]

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See detailWASP-16b: A New Jupiter-Like Planet Transiting a Southern Solar Analog
Lister, T. A.; Anderson, D. R.; Gillon, Michaël ULg et al

in Astrophysical Journal (2009), 703

We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity ... [more ▼]

We report the discovery from WASP-South of a new Jupiter-like extrasolar planet, WASP-16b, which transits its solar analog host star every 3.12 days. Analysis of the transit photometry and radial velocity spectroscopic data leads to a planet with R [SUB]p[/SUB] = 1.008 ± 0.071 R [SUB]Jup[/SUB] and M [SUB]p[/SUB] = 0.855 ± 0.059 M [SUB]Jup[/SUB], orbiting a host star with R [SUB]*[/SUB] = 0.946 ± 0.054 R [SUB]sun[/SUB] and M [SUB]*[/SUB] = 1.022 ± 0.101 M [SUB]sun[/SUB]. Comparison of the high resolution stellar spectrum with synthetic spectra and stellar evolution models indicates the host star is a near-solar metallicity ([Fe/H] =0.01 ± 0.10) solar analog (T [SUB]eff[/SUB] = 5700 ± 150 K and log g = 4.5 ± 0.2) of intermediate age (tau = 2.3[SUP]+5.8[/SUP] [SUB]--2.2[/SUB] Gyr). [less ▲]

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See detailDiscovery and characterization of WASP-6b, an inflated sub-Jupiter mass planet transiting a solar-type star
Gillon, Michaël ULg; Anderson, D. R.; Triaud, A H M J et al

in Astronomy and Astrophysics (2009), 501

We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060[SUP]+ 0.0000022 [/SUP][SUB]- 0.0000035 [/SUB] days a mildly metal-poor solar-type star of magnitude V ... [more ▼]

We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060[SUP]+ 0.0000022 [/SUP][SUB]- 0.0000035 [/SUB] days a mildly metal-poor solar-type star of magnitude V = 11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M[SUB]p[/SUB] = 0.503[SUP]+0.019[/SUP][SUB]-0.038[/SUB] M[SUB]J[/SUB] and radius R[SUB]p[/SUB] = 1.224[SUP]+0.051[/SUP][SUB]-0.052[/SUB] R_J, resulting in a density rho[SUB]p[/SUB] = 0.27 ± 0.05 rho_J. The mass and radius for the host star are M_ast = 0.88[SUP]+0.05[/SUP][SUB]-0.08[/SUB] M_o and R_ast = 0.870[SUP]+0.025[/SUP][SUB]-0.036[/SUB] R_o. The non-zero orbital eccentricity e = 0.054^+0.018[SUB]-0.015[/SUB] that we measure suggests that the planet underwent a massive tidal heating 1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis beta = 11[SUP]+14[/SUP][SUB]-18[/SUB] deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk. Based on data collected with the HARPS spectrograph at ESO La Silla Observatory in the programs 082.C-0040(E) and 082.C-0608. The photometric time-series and radial velocities (Tables 4, 5) used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/785 [less ▲]

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See detailThe Low Density Transiting Exoplanet WASP-15b
West, R. G.; Anderson, D. R.; Gillon, Michaël ULg et al

in Astronomical Journal (The) (2009), 137

We report the discovery of a low-density exoplanet transiting an 11th magnitude star in the Southern hemisphere. WASP-15b, which orbits its host star with a period P = 3.7520656 ± 0.0000028 d, has a mass ... [more ▼]

We report the discovery of a low-density exoplanet transiting an 11th magnitude star in the Southern hemisphere. WASP-15b, which orbits its host star with a period P = 3.7520656 ± 0.0000028 d, has a mass M [SUB]p[/SUB] = 0.542 ± 0.050 M [SUB]J[/SUB] and radius R [SUB]p[/SUB] = 1.428 ± 0.077 R [SUB]J[/SUB], and is therefore one of the least dense transiting exoplanets so far discovered (rho[SUB]p[/SUB] = 0.247 ± 0.035 g cm[SUP]--3[/SUP]). An analysis of the spectrum of the host star shows it to be of spectral type around F5, with an effective temperature T [SUB]eff[/SUB] = 6300 ± 100 K and [Fe/H] = --0.17 ± 0.11. [less ▲]

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See detailImproved parameters for the transiting hot Jupiters WASP-4b and WASP-5b
Gillon, Michaël ULg; Smalley, B.; Hebb, L. et al

in Astronomy and Astrophysics (2009), 496

The gaseous giant planets WASP-4b and WASP-5b are transiting 12-magnitude solar-type stars in the Southern hemisphere. The aim of the present work is to refine the parameters of these systems using high ... [more ▼]

The gaseous giant planets WASP-4b and WASP-5b are transiting 12-magnitude solar-type stars in the Southern hemisphere. The aim of the present work is to refine the parameters of these systems using high cadence VLT/FORS2 z-band transit photometry and high-resolution VLT/UVES spectroscopy. For WASP-4, the new estimates for the planet radius and mass from a combined analysis of our VLT data with previously published transit photometry and radial velocities are R[SUB]p[/SUB] = 1.30[SUP]+0.05[/SUP][SUB]-0.04[/SUB] R[SUB]J[/SUB] and M[SUB]p[/SUB] = 1.21[SUP]+0.13[/SUP][SUB]-0.08[/SUB] M_J, resulting in a density rho[SUB]p[/SUB] = 0.55[SUP]+0.04[/SUP][SUB]-0.02[/SUB] rho_J. The radius and mass for the host star are R_* = 0.87[SUP]+0.04[/SUP][SUB]-0.03[/SUB] R_o and M_* = 0.85[SUP]+0.11[/SUP][SUB]-0.07[/SUB] M_o. Our ground-based photometry reaches 550 ppm at time sampling of ~50 s. Nevertheless, we also report the presence of an instrumental effect on the VLT that degraded our photometry for the WASP-5 observations. This effect could be a major problem for similar programs. Our new estimates for the parameters of the WASP-5 system are R[SUB]p[/SUB] = 1.09 ± 0.07 R_J, M[SUB]p[/SUB] = 1.58[SUP]+0.13[/SUP][SUB]-0.10[/SUB] M_J, rho[SUB]p[/SUB] = 1.23 [SUP]+0.26[/SUP][SUB]-0.16[/SUB] rho_J, R_* = 1.03[SUP]+0.06[/SUP][SUB]-0.07[/SUB] R_o, and M_* = 0.96[SUP]+0.13[/SUP][SUB]-0.09[/SUB] M_o. The measured size of WASP-5b agrees well with the basic models of irradiated planets, while WASP-4b is clearly an ``anomalously'' large planet. Based on data collected with the FORS2 imager at the VLT-UT4 telescope and with the UVES spectrograph at the VLT-UT2 telescope (Paranal Observatory, ESO, Chile) in the programme 280.C-5003. [less ▲]

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See detailThe Masses and Radii of HD186753B and TYC7096-222-1B: The First M-dwarfs known to Eclipse A-type Stars
Bentley, S. J.; Smalley, B.; Maxted, P. F. L. et al

in Astronomy and Astrophysics (2009)

We present observations of two new single-lined eclipsing binaries, both consisting of an Am star and an M-dwarf, discovered by the Wide Angle Search for Planets transit photometry survey. Using WASP ... [more ▼]

We present observations of two new single-lined eclipsing binaries, both consisting of an Am star and an M-dwarf, discovered by the Wide Angle Search for Planets transit photometry survey. Using WASP photometry and spectroscopic measurements we find that HD186753B has an orbital period of $P=1.9194$ days, a mass of $M=0.24\pm0.02 M_{\odot}$ and radius of $R=0.31^{+0.06}_{-0.06} R_{\odot}$; and that TCY7096-222-1B has an orbital period of $P=8.9582$ days, a mass of between 0.29 and 0.54 $M_{\odot}$ depending on eccentricity and radius of $R=0.263^{+0.02}_{-0.07} R_{\odot}$. We find that the Am stars have relatively low rotational velocities that closely match the orbital velocities of the M-dwarfs, suggesting that they have been "spun-down" by the M-dwarfs. [less ▲]

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See detailPushing the precision limit of ground-based eclipse photometry
Gillon, Michaël ULg; Anderson, D. R.; Demory, B *-O et al

Report (2008)

Until recently, it was considered by many that ground-based photometry could not reach the high cadence sub-mmag regime because of the presence of the atmosphere. Indeed, high frequency atmospheric noises ... [more ▼]

Until recently, it was considered by many that ground-based photometry could not reach the high cadence sub-mmag regime because of the presence of the atmosphere. Indeed, high frequency atmospheric noises (mainly scintillation) limit the precision that high SNR photometry can reach within small time bins. If one is ready to damage the sampling of his photometric time-series, binning the data (or using longer exposures) allows to get better errors, but the obtained precision will be finally limited by low frequency noises. To observe several times the same planetary eclipse and to fold the photometry with the orbital period is thus generally considered as the only option to get very well sampled and precise eclipse light curve from the ground. Nevertheless, we show here that reaching the sub-mmag sub-min regime for one eclipse is possible with a ground-based instrument. This has important implications for transiting planets characterization, secondary eclipses measurement and small planets detection from the ground. [less ▲]

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See detailWASP-5b: a dense, very hot Jupiter transiting a 12th-mag Southern-hemisphere star
Anderson, D. R.; Gillon, Michaël ULg; Hellier, C. et al

in Monthly Notices of the Royal Astronomical Society (2008), 387

We report the discovery of WASP-5b, a Jupiter-mass planet orbiting a 12th-mag G-type star in the Southern hemisphere. The 1.6-d orbital period places WASP-5b in the class of very hot Jupiters and leads to ... [more ▼]

We report the discovery of WASP-5b, a Jupiter-mass planet orbiting a 12th-mag G-type star in the Southern hemisphere. The 1.6-d orbital period places WASP-5b in the class of very hot Jupiters and leads to a predicted equilibrium temperature of 1750K. WASP-5b is the densest of any known Jovian-mass planet, being a factor of 7 denser than TrES-4, which is subject to similar stellar insolation, and a factor of 3 denser than WASP-4b, which has a similar orbital period. We present transit photometry and radial velocity measurements of WASP-5 (= USNO-B10487-0799749), from which we derive the mass, radius and density of the planet: M[SUB]P[/SUB] = 1.58[SUP]+0.13[/SUP][SUB]-0.08[/SUB]M[SUB]J[/SUB],R[SUB]P[/SUB] = 1.090[SUP]+0.094[/SUP][SUB]-0.058[/SUB]R[SUB]J[/SUB] and rho[SUB]P[/SUB] = 1.22[SUP]+0.19[/SUP][SUB]-0.24[/SUB]rho[SUB]J[/SUB]. The orbital period is P = 1.6284296[SUP]+0.0000048[/SUP][SUB]-0.0000037[/SUB]d and the mid-transit epoch is T[SUB]C[/SUB](HJD) = 2454375.62466[SUP]+0.00026[/SUP][SUB]-0.00025[/SUB]. [less ▲]

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See detailWASP-4b: A 12th Magnitude Transiting Hot Jupiter in the Southern Hemisphere
Wilson, D. M.; Gillon, Michaël ULg; Hellier, C. et al

in Astrophysical Journal (2008), 675

We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period of 1.34 days. This is the first planet to be discovered by the SuperWASP-South observatory and CORALIE ... [more ▼]

We report the discovery of WASP-4b, a large transiting gas-giant planet with an orbital period of 1.34 days. This is the first planet to be discovered by the SuperWASP-South observatory and CORALIE collaboration and the first planet orbiting a star brighter than 16th magnitude to be discovered in the southern hemisphere. A simultaneous fit to high-quality light curves and precision radial velocity measurements leads to a planetary mass of 1.22[SUP]+0.09[/SUP][SUB]-0.08[/SUB] M[SUB]Jup[/SUB] and a planetary radius of 1.42[SUP]+0.07[/SUP][SUB]-0.04[/SUB] R[SUB]Jup[/SUB]. The host star is USNO-B1.0 0479-0948995, a G7 V star of visual magnitude 12.5. As a result of the short orbital period, the predicted surface temperature of the planet is 1761 K, making it an ideal candidate for detections of the secondary eclipse at infrared wavelengths. [less ▲]

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See detailWASP-1b and WASP-2b: two new transiting exoplanets detected with SuperWASP and SOPHIE
Cameron, A Collier; Bouchy, F.; Hébrard, G. et al

in Monthly Notices of the Royal Astronomical Society (2007), 375

We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219-0005465 (GSC 02265-00107 = WASP-1) and USNO-B1.0 0964-0543604 (GSC 00522-01199 = WASP-2). Both stars were identified ... [more ▼]

We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219-0005465 (GSC 02265-00107 = WASP-1) and USNO-B1.0 0964-0543604 (GSC 00522-01199 = WASP-2). Both stars were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radial-velocity variations and fits to the transit light curves yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 d, respectively. Given mass estimates for their F7V and K1V primaries, we derive planet masses 0.80-0.98 and 0.81-0.95 times that of Jupiter, respectively. WASP-1b appears to have an inflated radius of at least 1.33 R[SUB]Jup[/SUB], whereas WASP-2b has a radius in the range 0.65-1.26 R[SUB]Jup[/SUB]. [less ▲]

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