ORCID Profile
0000-0001-9823-1445
Current Organisation
The University of Edinburgh
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Publisher: American Astronomical Society
Date: 03-2021
Abstract: The light curve of KIC 8462852, aka Boyajian’s Star, undergoes deep dips the origin of which remains unclear. A faint star ≈2″ to the east was discovered in Keck/NIRC2 imaging in Boyajian et al., but its status as a binary, and possible contribution to the observed variability, was unclear. Here, we use three epochs of Keck/NIRC2 imaging, spanning 5 yr, in JHK near-infrared bands to obtain 1 mas precision astrometry. We show that the two objects exhibit common proper motion, measure a relative velocity of μ = 0.14 ± 0.44 mas yr −1 ( μ = 0.30 ± 0.93 km s −1 ) and conclude that they are a binary pair at 880 ± 10 au projected separation. There is marginal detection of possible orbital motion, but our astrometry is insufficient to characterize the orbit. We show that two other point sources are not associated with KIC 8462852. We recommend that attempts to model KIC 8462852 A’s light curve should revisit the possibility that the bound stellar companion may play a role in causing the irregular brightness variations, for ex le, through disruption of the orbits of bodies around the primary due to long-term orbital evolution of the binary orbit.
Publisher: American Astronomical Society
Date: 22-01-2019
Publisher: Oxford University Press (OUP)
Date: 03-2008
Publisher: American Astronomical Society
Date: 03-2023
Abstract: We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is a M Jup widely separated (∼8″, a = 150 au), young, planetary-mass companion that shares photometric colors and spectroscopic features with the directly imaged exoplanets HR 8799c, d, and e. As an L-to-T transition object, VHS 1256 b exists along the region of the color–magnitude diagram where substellar atmospheres transition from cloudy to clear. We observed VHS 1256 b with JWST's NIRSpec IFU and MIRI MRS modes for coverage from 1 to 20 μ m at resolutions of ∼1000–3700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium are observed in several portions of the JWST spectrum based on comparisons from template brown dwarf spectra, molecular opacities, and atmospheric models. The spectral shape of VHS 1256 b is influenced by disequilibrium chemistry and clouds. We directly detect silicate clouds, the first such detection reported for a planetary-mass companion.
Publisher: American Astronomical Society
Date: 15-07-2014
Publisher: American Astronomical Society
Date: 10-02-2009
Publisher: American Astronomical Society
Date: 09-11-2020
Publisher: American Astronomical Society
Date: 10-12-2008
DOI: 10.1086/591837
Publisher: Oxford University Press (OUP)
Date: 04-02-2022
Abstract: Planet formation is often considered in the context of one circumstellar disc around one star. Yet, stellar binary systems are ubiquitous, and thus a substantial fraction of all potential planets must form and evolve in more complex, dynamical environments. We present the results of a 5 yr astrometric monitoring c aign studying 45 binary star systems that host Kepler planet candidates. The planet-forming environments in these systems would have literally been shaped by the binary orbits that persist to the present day. Crucially, the mutual inclinations of star–planet orbits can only be addressed by a statistical s le. We describe in detail our s le selection and Keck/NIRC2 laser guide star adaptive optics observations collected from 2012 to 2017. We measure orbital arcs, with a typical accuracy of ∼0.1 mas yr−1, that test whether the binary orbits tend to be aligned with the edge-on transiting planet orbits. We rule out randomly distributed binary orbits at 4.7σ, and we show that low mutual inclinations are required to explain the observed orbital arcs. If the stellar orbits have a field binary-like eccentricity distribution, then the best match to our observed orbital arcs is a distribution of mutual inclinations ranging from 0° to 30°. We discuss the implications of such widespread planet–binary alignment in the theoretical context of planet formation and circumstellar disc evolution.
Publisher: American Astronomical Society
Date: 04-02-2020
Publisher: American Astronomical Society
Date: 07-2023
Abstract: We present JWST Early Release Science coronagraphic observations of the super-Jupiter exoplanet, HIP 65426b, with the Near-Infrared Camera (NIRCam) from 2 to 5 μ m, and with the Mid-Infrared Instrument (MIRI) from 11 to 16 μ m. At a separation of ∼0.″82 (87 − 31 + 108 au), HIP 65426b is clearly detected in all seven of our observational filters, representing the first images of an exoplanet to be obtained by JWST, and the first-ever direct detection of an exoplanet beyond 5 μ m. These observations demonstrate that JWST is exceeding its nominal predicted performance by up to a factor of 10, depending on separation and subtraction method, with measured 5 σ contrast limits of ∼1 × 10 −5 and ∼2 × 10 −4 at 1″ for NIRCam at 4.4 μ m and MIRI at 11.3 μ m, respectively. These contrast limits provide sensitivity to sub-Jupiter companions with masses as low as 0.3 M Jup beyond separations of ∼100 au. Together with existing ground-based near-infrared data, the JWST photometry are fit well by a BT-SETTL atmospheric model from 1 to 16 μ m, and they span ∼97% of HIP 65426b's luminous range. Independent of the choice of model atmosphere, we measure an empirical bolometric luminosity that is tightly constrained between log L bol / L ⊙ = −4.31 and −4.14, which in turn provides a robust mass constraint of 7.1 ± 1.2 M Jup . In totality, these observations confirm that JWST presents a powerful and exciting opportunity to characterize the population of exoplanets amenable to high-contrast imaging in greater detail.
Publisher: American Astronomical Society
Date: 03-08-2016
Publisher: American Astronomical Society
Date: 19-09-2019
Abstract: Planets occur most frequently around cool dwarfs, but only a handful of specific ex les are known to orbit the latest-type M stars. Using TESS photometry, we report the discovery of two planets transiting the low-mass star called LP 791-18 (identified by TESS as TOI 736). This star has spectral type M6V, effective temperature 2960 K, and radius 0.17 R ⊙ , making it the third-coolest star known to host planets. The two planets straddle the radius gap seen for smaller exoplanets they include a 1.1 R ⊕ planet on a 0.95 day orbit and a 2.3 R ⊕ planet on a 5 day orbit. Because the host star is small the decrease in light during these planets’ transits is fairly large (0.4% and 1.7%). This has allowed us to detect both planets’ transits from ground-based photometry, refining their radii and orbital ephemerides. In the future, radial velocity observations and transmission spectroscopy can both probe these planets’ bulk interior and atmospheric compositions, and additional photometric monitoring would be sensitive to even smaller transiting planets.
Publisher: American Astronomical Society
Date: 03-08-2016
Publisher: American Astronomical Society
Date: 25-01-2019
Publisher: American Astronomical Society
Date: 27-03-2023
Abstract: Binary stars are ubiquitous the majority of solar-type stars exist in binaries. Exoplanet occurrence rate is suppressed in binaries, but some multiples do still host planets. Binaries cause observational biases in planet parameters, with undetected multiplicity causing transiting planets to appear smaller than they truly are. We have analyzed the properties of a s le of 119 planet-host binary stars from the Kepler mission to study the underlying population of planets in binaries that fall in and around the radius valley, which is a demographic feature in period–radius space that marks the transition from predominantly rocky to predominantly gaseous planets. We found no statistically significant evidence for a radius gap for our s le of 122 planets in binaries when assuming that the primary stars are the planet hosts, with a low probability ( p 0.05) of the binary planet s le radius distribution being consistent with the single-star population of small planets via an Anderson–Darling test. These results reveal demographic differences in the planet size distribution between planets in binary and single stars for the first time, showing that stellar multiplicity may fundamentally alter the planet formation process. A larger s le and further assessment of circumprimary versus circumsecondary transits is needed to either validate this nondetection or explore other scenarios, such as a radius gap with a location that is dependent on binary separation.
Publisher: American Astronomical Society
Date: 08-06-2023
Abstract: We report the confirmation of three exoplanets transiting TOI-4010 (TIC-352682207), a metal-rich K dwarf observed by the Transiting Exoplanet Survey Satellite in Sectors 24, 25, 52, and 58. We confirm these planets with the High Accuracy Radial velocity Planet Searcher for the Northern Hemisphere radial velocity observations and measure their masses with 8−12% precision. TOI-4010 b is a sub-Neptune ( P = 1.3 days, R p = 3.02 − 0.08 + 0.08 R ⊕ , M p = 11.00 − 1.27 + 1.29 M ⊕ ) in the hot-Neptune desert, and is one of the few such planets with known companions. Meanwhile, TOI-4010 c ( P = 5.4 days, R p = 5.93 − 0.12 + 0.11 R ⊕ , M p = 20.31 − 2.11 + 2.13 M ⊕ ) and TOI-4010 d ( P = 14.7 days, R p = 6.18 − 0.14 + 0.15 R ⊕ , M p = 38.15 − 3.22 + 3.27 M ⊕ ) are similarly sized sub-Saturns on short-period orbits. Radial velocity observations also reveal a super-Jupiter-mass companion called TOI-4010 e in a long-period, eccentric orbit ( P ∼ 762 days and e ∼ 0.26 based on available observations). TOI-4010 is one of the few systems with multiple short-period sub-Saturns to be discovered so far.
Publisher: American Astronomical Society
Date: 12-10-2022
Abstract: Gliese 86 is a nearby K dwarf hosting a giant planet on a ≈16 day orbit and an outer white dwarf companion on a ≈century-long orbit. In this study we combine radial velocity data (including new measurements spanning more than a decade) with high angular resolution imaging and absolute astrometry from Hipparcos and Gaia to measure the current orbits and masses of both companions. We then simulate the evolution of the Gl 86 system to constrain its primordial orbit when both stars were on the main sequence the closest approach between the two stars was then about 9 au. Such a close separation limited the size of the protoplanetary disk of Gl 86 A and dynamically hindered the formation of the giant planet around it. Our measurements of Gl 86 B and Gl 86 Ab’s orbits reveal Gl 86 as a system in which giant planet formation took place in a disk truncated at ≈2 au. Such a disk would be just big enough to harbor the dust mass and total mass needed to assemble Gl 86 Ab’s core and envelope, assuming a high disk accretion rate and a low viscosity. Inefficient accretion of the disk onto Gl 86 Ab, however, would require a disk massive enough to approach the Toomre stability limit at its outer truncation radius. The orbital architecture of the Gl 86 system shows that giant planets can form even in severely truncated disks and provides an important benchmark for planet formation theory.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
No related grants have been discovered for Trent Dupuy.