NGTS-14Ab: a Neptune-sized transiting planet in the desert

Smith, A. M. S.; Acton, Jack S.; Anderson, D. R.; Bayliss, Daniel; Belardi, Claudia; Bouchy, F.; Brahm, R.; Briegal, Joshua T.; Bryant, Edward M.; Burleigh, M. R.; Cabrera, J.; Chaushev, Alexander; Cooke, Benjamin F.; Costes, Jean C.; Csizmadia, Sz.; Eigmüller, Ph.; Erikson, A.; Gill, Samuel; Gillen, Edward; Goad, M. R.; Günther, Maximilian N.; Henderson, Beth A.; Hogan, Aleisha; Jordán, Andrés; Lendl, M.; McCormac, J.; Moyano, Maximiliano; Nielsen, L. D.; Rauer, H.; Raynard, Liam; Tilbrook, Rosanna H.; Turner, O. D.; Udry, S.; Vines, José I.; Watson, Chris; West, R. G.; Wheatley, P. J.

doi:10.1051/0004-6361/202039712

Cited by 18 publications

(7 citation statements)

References 66 publications

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“…In particular, our simulations predict the transformation of the Jovian planet into hot Neptune via RLO. This scenario deserves attention in the context of the objects recently found in the Neptunian desert (West et al 2019;Smith et al 2021). A similar conclusion is made in Valsecchi et al (2015) and Jackson et al (2016).…”

Section: Discussionsupporting

confidence: 76%

Unraveling the evolution of hot Jupiter systems under the effect of tidal and magnetic interactions and mass loss

Lazovik¹

2023

Preprint

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Various interactions affect the population of close-in planets. Among them, the tidal and magnetic interactions drive orbital decay and star-planet angular momentum exchange, leading to stellar spin-up. As a result of the above processes, a planet may initiate the mass transfer to the host star once it encounters the Roche limit. Another mechanism providing substantial mass loss is associated with the atmospheric escape caused by photoevaporation followed by orbital expansion, which is thought to be important for hot Neptunes and super-Earths. Thus, the fraction of the initial number of hot Jupiters may transform into lowermass planets through the Roche-lobe overflow (RLO) phase and continue secular evolution under the effect of photoevaporation. In the present paper, we compile the latest prescriptions for tidal and magnetic migration and mass-loss rates to explore the dynamics of hot Jupiter systems. We study how the implemented interactions shape the orbital architecture of Jovian planets and whether their impact is enough to reproduce the observational sample. Our models suggest that the tidal interaction is able to generate the upper boundary of the hot Jupiter population in the mass-separation diagram. To recreate the sub-Jovian desert, we need to make additional assumptions regarding the RLO phase or the influence of the protoplanetary disc's inner edge on the initial planetary location. According to our estimates, 12-15 % of hot Jupiters around solar-mass stars have been engulfed or become lower-mass planets. 0.20-0.25 % of the present-day giant planet population undergoes decay intense enough to be detected with modern facilities.

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Section: Discussionsupporting

confidence: 76%

Unraveling the evolution of hot Jupiter systems under the effect of tidal and magnetic interactions and mass loss

Lazovik¹

2023

Preprint

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“…Each telescope is equipped with a 2K × 2K e2V deep-depleted Andor IKon-L CCD camera. It is optimized to detect and characterize transiting exoplanets around K-and early M-type stars and has achieved sufficient precision to disco v er e xoplanets as small as 3R ⊕ (Wheatley et al 2018 ;West et al 2019 ;Smith et al 2021 ).…”

Section: Ngtsmentioning

confidence: 99%

The discovery of three hot Jupiters, NGTS-23b, 24b, and 25b, and updated parameters for HATS-54b from the Next Generation Transit Survey

Jackson

Watson

Mooij

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We report the discovery of three new hot Jupiters with the Next Generation Transit Survey (NGTS) as well as updated parameters for HATS-54b, which was independently discovered by NGTS. NGTS-23b, NGTS-24b and NGTS-25b have orbital periods of 4.076, 3.468, and 2.823 days and orbit G-, F- and K-type stars, respectively. NGTS-24 and HATS-54 appear close to transitioning off the main-sequence (if they are not already doing so), and therefore are interesting targets given the observed lack of hot Jupiters around sub-giant stars. By considering the host star luminosities and the planets’ small orbital separations (0.037–0.050 au), we find that all four hot Jupiters are above the minimum irradiance threshold for inflation mechanisms to be effective. NGTS-23b has a mass of 0.61 MJ and radius of 1.27 RJ and is likely inflated. With a radius of 1.21 RJ and mass of 0.52 MJ, NGTS-24b has a radius larger than expected from non-inflated models but its radius is smaller than the predicted radius from current Bayesian inflationary models. Finally, NGTS-25b is intermediate between the inflated and non-inflated cases, having a mass of 0.64 MJ and a radius of 1.02 RJ. The physical processes driving radius inflation remain poorly understood, and by building the sample of hot Jupiters we can aim to identify the additional controlling parameters, such as metallicity and stellar age.

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“…The distributions for each model are averaged, weighted by the relative probability of each model, leading to smaller uncertainties than those obtained from any single model. ARIADNE has previously been used to characterize the primary star in several systems, both eclipsing binaries (Acton et al 2020), and exoplanetary systems (Smith et al 2021(Smith et al , 2022.…”

Section: Stellar Characterizationmentioning

confidence: 99%

A CHEOPS Search for Massive, Long-period Companions to the Warm Jupiter K2-139 b

Smith¹,

Csizmadia²

2022

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K2-139 b is a warm Jupiter with an orbital period of 28.4 days, but only three transits of this system have previously been observed–in the long-cadence mode of K2–limiting the precision with which the orbital period can be determined and future transits predicted. We report photometric observations of four transits of K2-139 b with ESA’s CHaracterising ExOPlanet Satellite (CHEOPS), conducted with the goal of measuring the orbital obliquity via spot-crossing events. We jointly fit these CHEOPS data alongside the three previously-published transits from the K2 mission, considerably increasing the precision of the ephemeris of K2-139 b. The transit times for this system can now be predicted for the next decade with a 1σ precision less than 10 minutes, compared to over one hour previously, allowing the efficient scheduling of observations with Ariel. We detect no significant deviation from a linear ephemeris, allowing us to exclude the presence of a massive outer planet orbiting with a period less than 150 days, or a brown dwarf with a period less than one year. We also determine the scaled semimajor axis, the impact parameter, and the stellar limb darkening with improved precision. This is driven by the shorter cadence of the CHEOPS observations compared to that of K2, and validates the subexposure technique used for analyzing long-cadence photometry. Finally, we note that the stellar spot configuration has changed from the epoch of the K2 observations; unlike the K2 transits, we detect no evidence of spot-crossing events in the CHEOPS data.

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NGTS-14Ab: a Neptune-sized transiting planet in the desert

Cited by 18 publications

References 66 publications

Unraveling the evolution of hot Jupiter systems under the effect of tidal and magnetic interactions and mass loss

Unraveling the evolution of hot Jupiter systems under the effect of tidal and magnetic interactions and mass loss

The discovery of three hot Jupiters, NGTS-23b, 24b, and 25b, and updated parameters for HATS-54b from the Next Generation Transit Survey

A CHEOPS Search for Massive, Long-period Companions to the Warm Jupiter K2-139 b

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