| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Alqasim, A., et al.
(författare)
-
TOI−757 b: an eccentric transiting mini−Neptune on a 17.5−d orbit
- 2024
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - 0035-8711 .- 1365-2966. ; 533:1, s. 1-26
-
Tidskriftsartikel (refereegranskat)abstract
- We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp = 10.5+−2212M, implying a bulk density of ρp = 3.6 ± 0.8 g cm−3. Our internal composition modelling was unable to constrain the composition of TOI−757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39+−000708, making it one of the very few highly eccentric planets among precisely characterized mini−Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI−757 b’s formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star−star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI−757.
|
|
| 7. |
|
|
| 8. |
- Luque, R., et al.
(författare)
-
A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067
- 2023
-
Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 623:7989, s. 932-937
-
Tidskriftsartikel (refereegranskat)abstract
- 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 1,2. However, their composition, formation and evolution remain poorly understood 3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R ⊕ to 2.85R ⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.
|
|
| 9. |
- Alcorn, J, et al.
(författare)
-
Basic instrumentation for Hall A at Jefferson Lab
- 2004
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
-
Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
|
|
| 10. |
- Bluhm, P., et al.
(författare)
-
Precise mass and radius of a transiting super-Earth planet orbiting the M dwarf TOI-1235: a planet in the radius gap?
- 2020
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 639
-
Tidskriftsartikel (refereegranskat)abstract
- We report the confirmation of a transiting planet around the bright weakly active M0.5 V star TOI-1235 (TYC 4384-1735-1, V ≈ 11.5 mag), whose transit signal was detected in the photometric time series of sectors 14, 20, and 21 of the TESS space mission. We confirm the planetary nature of the transit signal, which has a period of 3.44 d, by using precise RV measurements with the CARMENES, HARPS-N, and iSHELL spectrographs, supplemented by high-resolution imaging and ground-based photometry. A comparison of the properties derived for TOI-1235 b with theoretical models reveals that the planet has a rocky composition, with a bulk density slightly higher than that of Earth. In particular, we measure a mass of Mp = 5.9 ± 0.6 M⊕ and a radius of Rp = 1.69 ± 0.08 R⊕, which together result in a density of ρp = 6.7- 1.1+ 1.3 g cm-3. When compared with other well-characterized exoplanetary systems, the particular combination of planetary radius and mass places our discovery in the radius gap, which is a transition region between rocky planets and planets with significant atmospheric envelopes. A few examples of planets occupying the radius gap are known to date. While the exact location of the radius gap for M dwarfs is still a matter of debate, our results constrain it to be located at around 1.7 R⊕ or larger at the insolation levels received by TOI-1235 b (~60 S⊕). This makes it an extremely interesting object for further studies of planet formation and atmospheric evolution.
|
|
