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Pierre Maxted's Outputs (231)

The EBLM project – XIII. The absolute dynamical masses of the circumbinary planet host TOI-1338/BEBOP-1, and applications to the study of exoplanet atmospheres. (2024)
Journal Article
Sebastian, D., Triaud, A. H. M. J., Brogi, M., Baycroft, T. A., Standing, M. R., Maxted, P. F. L., …Nielsen, M. B. (2024). The EBLM project – XIII. The absolute dynamical masses of the circumbinary planet host TOI-1338/BEBOP-1, and applications to the study of exoplanet atmospheres. Monthly Notices of the Royal Astronomical Society, 530(3), 2572–2589. https://doi.org/10.1093/mnras/stae459

High-contrast eclipsing binaries with low mass M-dwarf secondaries are precise benchmark stars to build empirical mass-radius relationships for fully convective low-mass ($\rm M_{\star } < 0.35\, M_{\odot }$) dwarf stars. The contributed light... Read More about The EBLM project – XIII. The absolute dynamical masses of the circumbinary planet host TOI-1338/BEBOP-1, and applications to the study of exoplanet atmospheres..

Magnetic origin of the discrepancy between stellar limb-darkening models and observations (2024)
Journal Article
Kostogryz, N. M., Shapiro, A. I., Witzke, V., Cameron, R. H., Gizon, L., Krivova, N. A., …Valenti, J. (2024). Magnetic origin of the discrepancy between stellar limb-darkening models and observations. Nature Astronomy, 8(7), 929-937. https://doi.org/10.1038/s41550-024-02252-5

Stars appear darker at their limbs than at their disk centres because at the limb we are viewing the higher and cooler layers of stellar photospheres. Yet, limb darkening derived from state-of-the-art stellar atmosphere models systematically fails to... Read More about Magnetic origin of the discrepancy between stellar limb-darkening models and observations.

Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b (2024)
Journal Article
Demangeon, O. D. S., Cubillos, P. E., Singh, V., Wilson, T. G., Carone, L., Bekkelien, A., …Walton, N. A. (2024). Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b. Astronomy & Astrophysics, 684, Article A27. https://doi.org/10.1051/0004-6361/202348270

Context. WASP-76 b has been a recurrent subject of study since the detection of a signature in high-resolution transit spectroscopy data indicating an asymmetry between the two limbs of the planet. The existence of this asymmetric signature has been... Read More about Asymmetry in the atmosphere of the ultra-hot Jupiter WASP-76 b.

Planets observed with CHEOPS: Two super-Earths orbiting the red dwarf star TOI-776 (2024)
Journal Article
Fridlund, M., Georgieva, I. Y., Bonfanti, A., Alibert, Y., Persson, C. M., Gandolfi, D., …Walton, N. A. (2024). Planets observed with CHEOPS: Two super-Earths orbiting the red dwarf star TOI-776. Astronomy & Astrophysics, 684, Article A12. https://doi.org/10.1051/0004-6361/202243838

Context. M-dwarf stars are the most common of potential exoplanet host stars in the Galaxy. It is therefore very important to understand planetary systems orbiting such stars and to determine the physical parameters of such planets with high precisio... Read More about Planets observed with CHEOPS: Two super-Earths orbiting the red dwarf star TOI-776.

CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side (2024)
Journal Article
Singh, V., Scandariato, G., Smith, A. M. S., Cubillos, P. E., Lendl, M., Billot, N., …Zingales, T. (2024). CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side. Astronomy & Astrophysics, 683, Article A1. https://doi.org/10.1051/0004-6361/202347533

Context. Occultations are windows of opportunity to indirectly peek into the dayside atmosphere of exoplanets. High-precision transit events provide information on the spin-orbit alignment of exoplanets around fast-rotating hosts.

Aims. We aim to... Read More about CHEOPS observations of KELT-20 b/MASCARA-2 b: An aligned orbit and signs of variability from a reflective day side.

The EBLM Project– XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS (2024)
Journal Article
Swayne, M. I., Maxted, P. F. L., Triaud, A. H. M. J., Sousa, S. G., Deline, A., Ehrenreich, D., …Wilson, T. G. (2024). The EBLM Project– XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS. Monthly Notices of the Royal Astronomical Society, 528(4), 5703-5722. https://doi.org/10.1093/mnras/stad3866

Observations of low-mass stars have frequently shown a disagreement between observed stellar radii and radii predicted by theoretical stellar structure models. This ‘radius inflation’ problem could have an impact on both stellar and exoplanetary scie... Read More about The EBLM Project– XI. Mass, radius, and effective temperature measurements for 23 M-dwarf companions to solar-type stars observed with CHEOPS.

Constraining the reflective properties of WASP-178 b using CHEOPS photometry (2024)
Journal Article
Pagano, I., Scandariato, G., Singh, V., Lendl, M., Queloz, D., Simon, A. E., …Walton, N. A. (2024). Constraining the reflective properties of WASP-178 b using CHEOPS photometry. Astronomy & Astrophysics, 682, Article A102. https://doi.org/10.1051/0004-6361/202346705

Context. Multiwavelength photometry of the secondary eclipses of extrasolar planets is able to disentangle the reflected and thermally emitted light radiated from the planetary dayside. Based on this, we can measure the planetary geometric albedo Ag,... Read More about Constraining the reflective properties of WASP-178 b using CHEOPS photometry.

Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley (2024)
Journal Article
Bonfanti, A., Brady, M., Wilson, T. G., Venturini, J., Egger, J. A., Brandeker, A., …Zingales, T. (2024). Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley. Astronomy & Astrophysics, 682, Article A66. https://doi.org/10.1051/0004-6361/202348180

Context. TOI-732 is an M dwarf hosting two transiting planets that are located on the two opposite sides of the radius valley. Inferring a reliable demographics for this type of systems is key to understanding their formation and evolution mechanisms... Read More about Characterising TOI-732 b and c: New insights into the M-dwarf radius and density valley.

The EBLM Project—From False Positives to Benchmark Stars and Circumbinary Exoplanets (2023)
Journal Article
Maxted, P. F. L., Triaud, A. H. M. J., & Martin, D. V. (in press). The EBLM Project—From False Positives to Benchmark Stars and Circumbinary Exoplanets. Universe, 9(12), Article 498. https://doi.org/10.3390/universe9120498

The EBLM project aims to characterise very-low-mass stars that are companions to solar-type stars in eclipsing binaries. We describe the history and motivation for this project, the methodology we use to obtain the precise mass, radius, and effective... Read More about The EBLM Project—From False Positives to Benchmark Stars and Circumbinary Exoplanets.

A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067. (2023)
Journal Article
Luque, R., Osborn, H. P., Leleu, A., Pallé, E., Bonfanti, A., Barragán, O., …Zingales, T. (in press). A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067. Nature, 623(7989), 932-937. https://doi.org/10.1038/s41586-023-06692-3

Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars . However, their composition, formation and evolution remain poorly understood... Read More about A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067..

CHEOPS and TESS view of the ultra-short-period super-Earth TOI-561 b (2023)
Journal Article
Patel, J. A., Egger, J. A., Wilson, T. G., Bourrier, V., Carone, L., Beck, M., …Walton, N. A. (2023). CHEOPS and TESS view of the ultra-short-period super-Earth TOI-561 b. Astronomy & Astrophysics, 679, Article A92. https://doi.org/10.1051/0004-6361/202244946

Context. Ultra-short-period planets (USPs) are a unique class of super-Earths with an orbital period of less than a day, and hence they are subject to intense radiation from their host star. These planets cannot retain a primordial H/He atmosphere, a... Read More about CHEOPS and TESS view of the ultra-short-period super-Earth TOI-561 b.

Refining the properties of the TOI-178 system with CHEOPS and TESS (2023)
Journal Article
Delrez, L., Leleu, A., Brandeker, A., Gillon, M., Hooton, M. J., Collier Cameron, A., …Winn, J. N. (2023). Refining the properties of the TOI-178 system with CHEOPS and TESS. Astronomy & Astrophysics, 678, Article A200. https://doi.org/10.1051/0004-6361/202245479

Context. The TOI-178 system consists of a nearby late K-dwarf transited by six planets in the super-Earth to mini-Neptune regime, with radii ranging from ~1.1 to 2.9 R⊕ and orbital periods between 1.9 and 20.7 days. All planets but the innermost one... Read More about Refining the properties of the TOI-178 system with CHEOPS and TESS.

Refined parameters of the HD 22946 planetary system and the true orbital period of planet d (2023)
Journal Article
Garai, Z., Osborn, H. P., Gandolfi, D., Brandeker, A., Sousa, S. G., Lendl, M., …Walton, N. (2023). Refined parameters of the HD 22946 planetary system and the true orbital period of planet d. Astronomy & Astrophysics, 674, Article A44. https://doi.org/10.1051/0004-6361/202345943

Context. Multi-planet systems are important sources of information regarding the evolution of planets. However, the long-period planets in these systems often escape detection. These objects in particular may retain more of their primordial character... Read More about Refined parameters of the HD 22946 planetary system and the true orbital period of planet d.

TOI-5678b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS (2023)
Journal Article
Ulmer-Moll, S., Osborn, H. P., Tuson, A., Egger, J. A., Lendl, M., Maxted, P., …Walton, N. A. (2023). TOI-5678b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS. Astronomy & Astrophysics, 674, Article A43. https://doi.org/10.1051/0004-6361/202245478

Context. A large sample of long-period giant planets has been discovered thanks to long-term radial velocity surveys, but only a few dozen of these planets have a precise radius measurement. Transiting gas giants are crucial targets for the study of... Read More about TOI-5678b: A 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS.

Fundamental effective temperature measurements for eclipsing binary stars – IV. Selection of new benchmark stars and first results for HD 22064 (2023)
Journal Article
Maxted. (2023). Fundamental effective temperature measurements for eclipsing binary stars – IV. Selection of new benchmark stars and first results for HD 22064. Monthly Notices of the Royal Astronomical Society, 522(2), 2683 - 2695. https://doi.org/10.1093/mnras/stad1112

I describe the selection and initial characterization of 20 eclipsing binary stars that are suitable for calibration and testing of stellar models and data analysis algorithms used by the PLATO mission and spectroscopic surveys. The binary stars sele... Read More about Fundamental effective temperature measurements for eclipsing binary stars – IV. Selection of new benchmark stars and first results for HD 22064.

TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf HD 15906 (2023)
Journal Article
Tuson, A., Queloz, D., Osborn, H. P., Wilson, T. G., Hooton, M. J., Beck, M., …Wohler, B. (2023). TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf HD 15906. Monthly Notices of the Royal Astronomical Society, 523(2), 3090-3118. https://doi.org/10.1093/mnras/stad1369

We report the discovery of two warm sub-Neptunes transiting the bright (G = 9.5 mag) K-dwarf HD 15906 (TOI 461, TIC 4646810). This star was observed by the Transiting Exoplanet Survey Satellite (TESS) in sectors 4 and 31, revealing two small transiti... Read More about TESS and CHEOPS discover two warm sub-Neptunes transiting the bright K-dwarf HD 15906.

Two warm Neptunes transiting HIP 9618 revealed by <i>TESS</i> and <i>Cheops</i> (2023)
Journal Article
Osborn, H. P., Nowak, G., Hébrard, G., Masseron, T., Lillo-Box, J., Pallé, E., …Winn, J. N. (2023). Two warm Neptunes transiting HIP 9618 revealed by TESS and Cheops. Monthly Notices of the Royal Astronomical Society, 523(2), 3069-3089. https://doi.org/10.1093/mnras/stad1319

HIP 9618 (HD 12572, TOI-1471, TIC 306263608) is a bright (G = 9.0 mag) solar analogue. TESS photometry revealed the star to have two candidate planets with radii of 3.9 ± 0.044 R⊕ (HIP 9618 b) and 3.343 ± 0.039 R⊕ (HIP 9618 c). While the 20.77291 d p... Read More about Two warm Neptunes transiting HIP 9618 revealed by <i>TESS</i> and <i>Cheops</i>.