| 1. |
- Korth, J., et al.
(författare)
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TOI-1130: A photodynamical analysis of a hot Jupiter in resonance with an inner low-mass planet
- 2023
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Ingår i: Astronomy & Astrophysics. - 1432-0746 .- 0004-6361. ; 675
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Tidskriftsartikel (refereegranskat)abstract
- The TOI-1130 is a known planetary system around a K-dwarf consisting of a gas giant planet, TOI-1130 c on an 8.4-day orbit that is accompanied by an inner Neptune-sized planet, TOI-1130 b, with an orbital period of 4.1 days. We collected precise radial velocity (RV) measurements of TOI-1130 with the HARPS and PFS spectrographs as part of our ongoing RV follow-up program. We performed a photodynamical modeling of the HARPS and PFS RVs, along with transit photometry from the Transiting Exoplanet Survey Satellite (TESS) and the TESS Follow-up Observing Program (TFOP). We determined the planet masses and radii of TOI-1130 b and TOI-1130 c to be Mb = 19.28 ± 0.97M⊕ and Rb = 3.56 ± 0.13 R⊕, and Mc = 325.59 ± 5.59M⊕ and Rc = 13.32−1.41+1.55 R⊕, respectively. We have spectroscopically confirmed the existence of TOI-1130 b, which had previously only been validated. We find that the two planets have orbits with small eccentricities in a 2:1 resonant configuration. This is the first known system with a hot Jupiter and an inner lower mass planet locked in a mean-motion resonance. TOI-1130 belongs to the small, yet growing population of hot Jupiters with an inner low-mass planet that poses a challenge to the pathway scenario for hot Jupiter formation. We also detected a linear RV trend that is possibly due to the presence of an outer massive companion.
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| 2. |
- Psaridi, A., et al.
(författare)
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Discovery of two warm mini-Neptunes with contrasting densities orbiting the young K3V star TOI-815
- 2024
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
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Tidskriftsartikel (refereegranskat)abstract
- We present the discovery and characterization of two warm mini-Neptunes transiting the K3V star TOI-815 in a K–M binary system. Analysis of its spectra and rotation period reveal the star to be young, with an age of 200+−400200 Myr. TOI-815b has a 11.2-day period and a radius of 2.94 ± 0.05 R+ with transits observed by TESS, CHEOPS, ASTEP, and LCOGT. The outer planet, TOI-815c, has a radius of 2.62 ± 0.10 R+, based on observations of three nonconsecutive transits with TESS; targeted CHEOPS photometry and radial velocity follow-up with ESPRESSO were required to confirm the 35-day period. ESPRESSO confirmed the planetary nature of both planets and measured masses of 7.6 ± 1.5 M+ (ρP = 1.64+−003331 g cm−3) and 23.5 ± 2.4 M+ (ρP = 7.2+−1110 g cm−3), respectively. Thus, the planets have very different masses, which is unusual for compact multi-planet systems. Moreover, our statistical analysis of mini-Neptunes orbiting FGK stars suggests that weakly irradiated planets tend to have higher bulk densities compared to those undergoing strong irradiation. This could be ascribed to their cooler atmospheres, which are more compressed and denser. Internal structure modeling of TOI-815b suggests it likely has a H-He atmosphere that constitutes a few percent of the total planet mass, or higher if the planet is assumed to have no water. In contrast, the measured mass and radius of TOI-815c can be explained without invoking any atmosphere, challenging planetary formation theories. Finally, we infer from our measurements that the star is viewed close to pole-on, which implies a spin-orbit misalignment at the 3σ level. This emphasizes the peculiarity of the system’s orbital architecture, and probably hints at an eventful dynamical history.
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| 3. |
- Bordé, P., et al.
(författare)
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Transiting exoplanets from the CoRoT space mission: XXIX. The hot Jupiters CoRoT-30 b and CoRoT-31 b
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope. Methods. We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To derive the absolute masses and radii of the planets, we modeled the stars from available magnitudes and spectra. Results. We find that CoRoT-30 b is a warm Jupiter on a close-to-circular 9.06-day orbit around a G3V star with a semi-major axis of about 0.08 AU. It has a radius of 1.01 ± 0.08 RJ, a mass of 2.90 ± 0.22 MJ, and therefore a mean density of 3.45 ± 0.65 g cm-3. The hot Jupiter CoRoT-31 b is on a close-to-circular 4.63-day orbit around a G2 IV star with a semi-major axis of about 0.05 AU. It has a radius of 1.46 ± 0.30 RJ, a mass of 0.84 ± 0.34 MJ, and therefore a mean density of 0.33 ± 0.18 g cm-3. Conclusions. Neither system seems to support the claim that stars hosting planets are more depleted in lithium. The radii of both planets are close to that of Jupiter, but they differ in mass; CoRoT-30 b is ten times denser than CoRoT-31 b. The core of CoRoT-30 b would weigh between 15 and 75 Earth masses, whereas relatively weak constraints favor no core for CoRoT-31 b. In terms of evolution, the characteristics of CoRoT-31 b appear to be compatible with the high-eccentricity migration scenario, which is not the case for CoRoT-30 b. The angular momentum of CoRoT-31 b is currently too low for the planet to evolve toward synchronization of its orbital revolution with stellar rotation, and the planet will slowly spiral-in while its host star becomes a red giant. CoRoT-30 b is not synchronized either: it looses angular momentum owing to stellar winds and is expected reach steady state in about 2 Gyr. CoRoT-30 and 31, as a pair, are a truly remarkable example of diversity in systems with hot Jupiters.
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| 4. |
- Hawthorn, F., et al.
(författare)
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TOI-836: A super-Earth and mini-Neptune transiting a nearby K-dwarf
- 2023
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 520:3, s. 3649-3668
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Tidskriftsartikel (refereegranskat)abstract
- We present the discovery of two exoplanets transiting TOI-836 (TIC 440887364) using data from TESS Sector 11 and Sector 38. TOI-836 is a bright (T = 8.5 mag), high proper motion (∼200 mas yr−1), low metallicity ([Fe/H]≈−0.28) K-dwarf with a mass of 0.68 ± 0.05 M and a radius of 0.67 ± 0.01 R. We obtain photometric follow-up observations with a variety of facilities, and we use these data sets to determine that the inner planet, TOI-836 b, is a 1.70 ± 0.07 R super-Earth in a 3.82-d orbit, placing it directly within the so-called ‘radius valley’. The outer planet, TOI-836 c, is a 2.59 ± 0.09 R mini-Neptune in an 8.60-d orbit. Radial velocity measurements reveal that TOI-836 b has a mass of 4.5 ± 0.9 M, while TOI-836 c has a mass of 9.6 ± 2.6 M. Photometric observations show Transit Timing Variations (TTVs) on the order of 20 min for TOI-836 c, although there are no detectable TTVs for TOI-836 b. The TTVs of planet TOI-836 c may be caused by an undetected exterior planet.
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| 5. |
- Pearson, A. D. J., et al.
(författare)
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Paediatric Strategy Forum for medicinal product development for acute myeloid leukaemia in children and adolescents ACCELERATE in collaboration with the European Medicines Agency with participation of the Food and Drug Administration
- 2020
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Ingår i: European Journal of Cancer. - : Elsevier BV. - 0959-8049. ; 136, s. 116-129
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The current standard-of-care for front-line therapy for acute myeloid leukaemia (AML) results in short-term and long-term toxicity, but still approximately 40% of children relapse. Therefore, there is a major need to accelerate the evaluation of innovative medicines, yet drug development continues to be adult-focused. Furthermore, the large number of competing agents in rare patient populations requires coordinated prioritisation, within the global regulatory framework and cooperative group initiatives. Methods: The fourth multi-stakeholder Paediatric Strategy Forum focused on AML in children and adolescents. Results: CD123 is a high priority target and the paediatric development should be accelerated as a proof-of-concept. Efforts must be coordinated, however, as there are a limited number of studies that can be delivered. Studies of FLT3 inhibitors in agreed paediatric investigation plans present challenges to be completed because they require enrolment of a larger number of patients than actually exist. A consensus was developed by industry and academia of optimised clinical trials. For AML with rare mutations that are more frequent in adolescents than in children, adult trials should enrol adolescents and when scientifically justified, efficacy data could be extrapolated. Methodologies and definitions of minimal residual disease need to be standardised internationally and validated as a new response criterion. Industry supported, academic sponsored platform trials could identify products to be further developed. The Leukaemia and Lymphoma Society PedAL/EUpAL initiative has the potential to be a major advance in the field. Conclusion: These initiatives continue to accelerate drug development for children with AML and ultimately improve clinical outcomes. (C) 2020 Elsevier Ltd. All rights reserved.
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| 6. |
- Hobson, Melissa J., et al.
(författare)
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TOI-199 b : A Well-characterized 100 day Transiting Warm Giant Planet with TTVs Seen from Antarctica
- 2023
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Ingår i: Astronomical Journal. - 0004-6256. ; 166:5
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Tidskriftsartikel (refereegranskat)abstract
- We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5 hr long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199 b has a 104.854 − 0.002 + 0.001 day period, a mass of 0.17 ± 0.02 M J, and a radius of 0.810 ± 0.005 R J. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations (TTVs), pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the nontransiting companion TOI-199 c, which has a period of 273.69 − 0.22 + 0.26 days and an estimated mass of 0.28 − 0.01 + 0.02 M J . This period places it within the conservative habitable zone.
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| 7. |
- Lefrancq, Noemie, et al.
(författare)
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Global spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis
- 2022
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 14:642
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Tidskriftsartikel (refereegranskat)abstract
- As with other pathogens, competitive interactions between Bordetella pertussis strains drive infection risk. Vaccines are thought to perturb strain diversity through shifts in immune pressures; however, this has rarely been measured because of inadequate data and analytical tools. We used 3344 sequences from 23 countries to show that, on average, there are 28.1 transmission chains circulating within a subnational region, with the number of chains strongly associated with host population size. It took 5 to 10 years for B. pertussis to be homogeneously distributed throughout Europe, with the same time frame required for the United States. Increased fitness of pertactin-deficient strains after implementation of acellular vaccines, but reduced fitness otherwise, can explain long-term genotype dynamics. These findings highlight the role of vaccine policy in shifting local diversity of a pathogen that is responsible for 160,000 deaths annually.
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| 8. |
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