ORCID Profile
0000-0002-6174-4666
Current Organisation
University of St Andrews
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Publisher: EDP Sciences
Date: 02-2022
DOI: 10.1051/0004-6361/202141429
Abstract: We present the discovery and characterization of a transiting sub-Neptune that orbits the nearby (28 pc) and bright ( V = 8.37) K0V star HD 207897 (TOI-1611) with a 16.20-day period. This discovery is based on photometric measurements from the Transiting Exoplanet Survey Satellite mission and radial velocity (RV) observations from the SOPHIE, Automated Planet Finder, and HIRES high-precision spectrographs. We used EXOFASTv2 to model the parameters of the planet and its host star simultaneously, combining photometric and RV data to determine the planetary system parameters. We show that the planet has a radius of 2.50 ± 0.08 R E and a mass of either 14.4 ± 1.6 M E or 15.9 ± 1.6 M E with nearly equal probability. The two solutions correspond to two possibilities for the stellar activity period. The density accordingly is either 5.1 ± 0.7 g cm −3 or 5.5 −0.7 +0.8 g cm −3 , making it one of the relatively rare dense sub-Neptunes. The existence of this dense planet at only 0.12 AU from its host star is unusual in the currently observed sub-Neptune (2 R E 4) population. The most likely scenario is that this planet has migrated to its current position.
Publisher: Springer Science and Business Media LLC
Date: 14-09-2020
Publisher: EDP Sciences
Date: 28-10-2022
DOI: 10.1051/0004-6361/202243093
Abstract: We present the discovery of two small planets transiting HD 93963A (TOI-1797), a GOV star ( M * = 1.109 ± 0.043 M ⊙ , R * = 1.043 ± 0.009 R ⊙ ) in a visual binary system. We combined TESS and CHEOPS space-borne photometry with MuSCAT 2 ground-based photometry, ‘Alopeke and PHARO high-resolution imaging, TRES and FIES reconnaissance spectroscopy, and SOPHIE radial velocity measurements. We validated and spectroscopically confirmed the outer transiting planet HD 93963 A c, a sub-Neptune with an orbital period of P c ≈ 3.65 d that was reported to be a TESS object of interest (TOI) shortly after the release of Sector 22 data. HD 93963 A c has amass of M c = 19.2 ± 4.1 M ⊕ and a radius of R c = 3.228 ± 0.059 R ⊕ , implying a mean density of ρ c = 3.1 ± 0.7 g cm -3 . The inner object, HD 93963 A b, is a validated 1.04 d ultra-short period (USP) transiting super-Earth that we discovered in the TESS light curve and that was not listed as a TOI, owing to the low significance of its signal (TESS signal-to-noise ratio ≈6.7, TESS + CHEOPS combined transit depth D b = 141.5 −8.3 +8.5 ppm). We intensively monitored the star with CHEOPS by performing nine transit observations to confirm the presence of the inner planet and validate the system. HD 93963 A b is the first small ( R b = 1.35 ± 0.042 R ⊕ ) USP planet discovered and validated by TESS and CHEOPS. Unlike planet c, HD 93963 Ab is not significantly detected in our radial velocities ( M b = 7.8 ± 3.2 M ⊕ ). The two planets are on either side of the radius valley, implying that they could have undergone completely different evolution processes. We also discovered a linear trend in our Doppler measurements, suggesting the possible presence of a long-period outer planet. With a V -band magnitude of 9.2, HD 93963 A is among the brightest stars known to host a USP planet, making it one of the most favourable targets for precise mass measurement via Doppler spectroscopy and an important laboratory to test formation, evolution, and migration models of planetary systems hosting ultra-short period planets.
Publisher: Springer Science and Business Media LLC
Date: 13-10-2020
Publisher: American Astronomical Society
Date: 10-05-2023
Abstract: We report the discovery of TOI-4127 b, which is a transiting, Jupiter-sized exoplanet on a long-period ( P = 56.39879 − 0.00010 + 0.00010 days) and a high-eccentricity orbit around a late F-type dwarf star. This warm Jupiter was first detected and identified as a promising candidate from a search for single-transit signals in TESS Sector 20 data, and was later characterized as a planet following two subsequent transits (TESS Sectors 26 and 53) and follow-up ground-based RV observations with the NEID and SOPHIE spectrographs. We jointly fit the transit and RV data to constrain the physical ( R p = 1.096 − 0.032 + 0.039 R J , M p = 2.30 − 0.11 + 0.11 M J ) and orbital parameters of the exoplanet. Given its high orbital eccentricity ( e = 0.7471 − 0.0086 + 0.0078 ), TOI-4127 b is a compelling candidate for studies of warm Jupiter populations and of hot Jupiter formation pathways. We show that the present periastron separation of TOI-4127 b is too large for high-eccentricity tidal migration to circularize its orbit, and that TOI-4127 b is unlikely to be a hot Jupiter progenitor unless it is undergoing angular momentum exchange with an undetected outer companion. Although we find no evidence for an external companion, the available observational data are insufficient to rule out the presence of a perturber that can excite eccentricity oscillations and facilitate tidal migration.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Pía Cortés-Zuleta.