Astronomia UDP

James Jenkins

I am a full professor working on the search and characterization of planets orbiting stars other than the Sun, so-called exoplanets, with a focus on using the radial-velocity method of planet detection to uncover new planets orbiting nearby stars. I also use this method to confirm planet candidates detected by transiting surveys like TESS and NGTS. I use ground-based and space-based facilities to study the atmospheres of low-mass planets, aiming to uncover their chemical constituents and physical process, which will allow us to shed light on their formation and evolutionary processes. Finally, I develop new statistical tools to aid in the discovery of these new planets and to better understand the nature of their host stars.

Current Position: Full professor (Titular)

Projects

Within my group, we use the radial-velocity (RV) method to detect small rocky planets orbiting the nearest stars to the Sun, those with the best opportunities for future follow-up to better understand their nature. We also use this method to confirm and measure the masses of planet candidates that have first been uncovered by transiting programs like the Transiting Exoplanet Survey Satellite (TESS) or the Next Generation Transit Survey (NGTS). With the combined sizes from the transits and the masses from the RVs, we can measure precise densities for the planets and therefore estimate their bulk compositions, for example, whether they are just large rocks or rocks with atmospheres surrounding them. As part of my work to better characterize the exoplanet population, we use ground-based high-resolution spectroscopy to search for specific atomic and molecular species that exist in planetary atmospheres. Here we pay special attention to extreme planets in the Neptune Desert region of parameter space, a region very close to stars devoid of planets like Neptune. We try to discover and study new Desert candidates, particularly looking for LTT9779b-analogues, which is a planet we discovered in the Desert, and for reasons we are trying to understand, hosts a large atmosphere around its rocky core. We also study these planets with space-based facilities like CHEOPS and JWST to further uncover their physical nature, their cloud properties, and heat distributions, with the goal of better understanding the physics that explains planet formation and evolution. Finally, we develop new tools using Bayesian Statistics that aids us in the search for small signals buried within the stellar and instrumental noise sources. We have developed codes like ARIADNE that implement Bayesian Model Averaging to precisely and accurately measure the radii of stars, which then filters down into the measurement of planetary radii. In addition, we are in the development of a program called EMPEROR that detects and characterizes small signals in combined RV, transit, and astrometric data, employing Bayesian and Markov chain Monte Carlo methods, whilst simultaneously modeling the uncorrelated and correlated noise sources in the combined data sets.

Highlights

  • Universidad de Chile, Recognition of High Impact Research 2017
  • P.I. The Chile-Hertfordshire Extrasolar Planet Search (CHEPS) Chilean
  • P.I. the Next Generation Planet Search (NGTS)
  • Anglada-Escude et al. 2016, Nature, 536, 437, ‘A terrestrial planet candidate in a temperate orbit around Proxima Centauri’
  • Jenkins et al. 2020, Nature Astronomy, 4, 1148, ‘An ultrahot Neptune in the Neptune desert’

Publications

https://ui.adsabs.harvard.edu/user/libraries/E2BumGTVSqm5g0LIU_Gc9A

Extracurricular activities

I enjoy watching and playing football, and I am an active Crossfitter. Traveling is also a passion of mine, and I particularly enjoy visiting areas of historical interest around the world.