20 research outputs found
Kiyang-yang, a West-African Postwar Idiom of Distress
In 1984, a healing cult for young barren women in southern Guinea Bissau developed into a movement, Kiyang-yang, that shook society to its foundations and had national repercussions. âIdiom of distressâ is used here as a heuristic tool to understand how Kiyang-yang was able to link war and post-war-related traumatic stress and suffering on both individual and group levels. An individual experience born from a traumatic origin may be generalized into an idiom that diverse sectors of society could embrace for a range of related reasons. We argue that, for an idiom to be understood and appropriated by others, there has to be resonance at the level of symbolic language and shared experiences as well as at the level of the culturally mediated contingent emotions it communicates. We also argue that through its symbolic references to structural causes of suffering, an idiom of distress entails a danger for those in power. It can continue to exist only if its etiology is not exposed or the social suffering it articulates is not eliminated. We finally argue that idioms of distress are not to be understood as discrete diagnostic categories or as monodimensional expressions of âtraumaâ that can be addressed
TOI-222: A single-transit TESS candidate revealed to be a 34-d eclipsing binary with CORALIE, EulerCam, and NGTS
We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based photometric detection of two subsequent transits. Our data show that the companion to TOI-222 is a low-mass star, with a radius of 0.18+â003910 Râ and a mass of 0.23 ± 0.01 Mâ. This discovery showcases the ability to efficiently discover long-period systems from TESS single-transit events using a combination of radial velocity monitoring coupled with high-precision ground-based photometry
An ultrahot Neptune in the Neptune desert
About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet1,2. All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (Râ), or apparently rocky planets smaller than 2 Râ. Such lack of planets of intermediate size (the âhot Neptune desertâ) has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 Râ and a mass of 29 Mâ, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite3 revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planetâs mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0â2.9+2.7% of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this âultrahot Neptuneâ managed to retain such an envelope. Follow-up observations of the planetâs atmosphere to better understand its origin and physical nature will be facilitated by the starâs brightness (Vmag = 9.8)
A remnant planetary core in the hot-Neptune desert
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune âdesertâ1,2 (a region in massâradius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptuneâs but an anomalously large mass of 39.1â2.6+2.7 Earth masses and a density of 5.2â0.8+0.7 grams per cubic centimetre, similar to Earthâs. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than 3.9â0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet
A remnant planetary core in the hot-Neptune desert
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune âdesertâ1,2 (a region in massâradius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptuneâs but an anomalously large mass of
Earth masses and a density of
grams per cubic centimetre, similar to Earthâs. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than
per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet
TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
Stars and planetary system
TOI-431/HIP 26013: A super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
We present the bright (Vmag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 ± 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Satellite (TESS) objects of Interest (TOI)-431 b is a super-Earth with a period of 0.49 d, a radius of 1.28 ± 0.04 R, a mass of 3.07 ± 0.35 M, and a density of 8.0 ± 1.0 g cm-3; TOI-431 d is a sub-Neptune with a period of 12.46 d, a radius of 3.29 ± 0.09 R, a mass of 9.90+1.53-1.49 M, and a density of 1.36 ± 0.25 g cm-3. We find a third planet, TOI-431 c, in the High Accuracy Radial velocity Planet Searcher RV data, but it is not seen to transit in the TESS light curves. It has an Msin i of 2.83+0.41-0.34 M, and a period of 4.85 d. TOI-431 d likely has an extended atmosphere and is one of the most well-suited TESS discoveries for atmospheric characterization, while the super-Earth TOI-431 b may be a stripped core. These planets straddle the radius gap, presenting an interesting case-study for atmospheric evolution, and TOI-431 b is a prime TESS discovery for the study of rocky planet phase curves