| 1. |
- Carmichael, Theron W., et al.
(författare)
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Two Intermediate-mass Transiting Brown Dwarfs from the TESS Mission
- 2020
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Ingår i: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 160:1
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery of two intermediate-mass transiting brown dwarfs (BDs), TOI-569b and TOI-1406b, from NASA's Transiting Exoplanet Survey Satellite mission. TOI-569b has an orbital period of P=.55604±0.00016 days, a mass of Mb = 64.1±1.9 MJ, and a radius of Rb = 0.75±0.02 RJ. Its host star, TOI-569, has a mass of Må = 1.21±0.05 M, a radius of Rå = 1.47±0.03 R, [Fe H 0.29 0.09] = + dex, and an effective temperature of Teff = 5768±10K. TOI-1406b has an orbital period of P=10.57415±0.00063 days, a mass of Mb = 46.0± 2.7 MJ, and a radius of Rb = 0.86±0.03 RJ. The host star for this BD has a mass of Må = 1.18±0.09 M, a radius of Rå = 1.35±0.03 R, [Fe/H] =-0.08± 0.09 dex, and an effective temperature of Teff = 6290±100 K. Both BDs are in circular orbits around their host stars and are older than 3 Gyr based on stellar isochrone models of the stars. TOI-569 is one of two slightly evolved stars known to host a transiting BD (the other being KOI-415). TOI-1406b is one of three known transiting BDs to occupy the mass range of 40-50 MJ and one of two to have a circular orbit at a period near 10 days (with the first being KOI-205b). Both BDs have reliable ages from stellar isochrones, in addition to their well-constrained masses and radii, making them particularly valuable as tests for substellar isochrones in the BD mass-radius diagram.
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| 2. |
- Prinoth, Bibiana, et al.
(författare)
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Titanium oxide and chemical inhomogeneity in the atmosphere of the exoplanet WASP-189 b
- 2022
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Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; 6:4, s. 449-457
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Tidskriftsartikel (refereegranskat)abstract
- The temperature of an atmosphere decreases with increasing altitude, unless a shortwave absorber that causes a temperature inversion exists. Ozone plays this role in the Earth’s atmosphere. In the atmospheres of highly irradiated exoplanets, the shortwave absorbers are predicted to be titanium oxide (TiO) and vanadium oxide (VO). Detections of TiO and VO have been claimed using both low-, and high- spectral-resolution observations, but subsequent observations have failed to confirm these claims or overturned them. Here we report the unambiguous detection of TiO in the ultra-hot Jupiter WASP-189 b using high-resolution transmission spectroscopy. This detection is based on applying the cross-correlation technique to many spectral lines of TiO from 460 to 690 nm. Moreover, we report detections of metals, including neutral and singly ionized iron and titanium, as well as chromium, magnesium, vanadium and manganese (Fe, Fe+, Ti, Ti+, Cr, Mg, V, Mn). The line positions of the detected species differ, which we interpret as a consequence of spatial gradients in their chemical abundances, such that they exist in different regions or dynamical regimes. This is direct observational evidence for the three-dimensional thermochemical stratification of an exoplanet atmosphere derived from high-resolution ground-based spectroscopy.
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| 3. |
- Seidel, Julia V., et al.
(författare)
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Detection of atmospheric species and dynamics in the bloated hot Jupiter WASP-172 b with ESPRESSO
- 2023
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 678
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Tidskriftsartikel (refereegranskat)abstract
- Context. The population of strongly irradiated Jupiter-sized planets has no equivalent in the Solar System. It is characterised by strongly bloated atmospheres and large atmospheric scale heights. Recent space-based observations of SO2 photochemistry have demonstrated the knowledge that can be gained about Earth's uniqueness from detailed atmospheric studies of these unusual planets. Aims. Here we explore the atmosphere of WASP-172 b, a planet similar in terms of temperature and bloating to the recently studied HD 149026 b. We characterise the atmospheric composition and subsequently the atmospheric dynamics of this prime target. Methods. We observed a particular transit of WASP-172 b in front of its host star with ESO's ESPRESSO spectrograph and analysed the spectra obtained before, during, and after transit. Results. We detect the absorption of starlight by WASP-172 b's atmosphere by sodium (5.6 ) and hydrogen (19.5 ) and obtained a tentative detection of iron (4.1 ). We detect strong yet varying blueshifts, relative to the planetary rest frame, of all of these absorption features. This allows for a preliminary study of the atmospheric dynamics of WASP-172 b. Conclusions. With only one transit, we were able to detect a wide variety of species that clearly track different atmospheric layers with possible jets. WASP-172 b is a prime follow-up target for a more in-depth characterisation with both ground- and space-based observatories. If the detection of Fe is confirmed, this may suggest that radius inflation is an important determinant for the detectability of Fe in hot Jupiters, as several non-detections of Fe have been published for planets that are hotter but less inflated than WASP-172 b.
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