(July 2024) Members of the TRAPPIST-1 Community Initiative, including Adam Burgasser, have published a Nature Astronomy Perspective presenting a roadmap for study of the multi-planet systems around mid- and late-M dwarf stars like TRAPPIST-1 with JWST. Multi-planet systems are particularly useful for correcting for flare and spot modulations from the star, which can overwhelm any atmosphere detection. The specific plan advocated is to first conduct MIRI emission observations to first assess the presence of an atmosphere among inner planets, which can be inferred from phase variation. When there are inner planets lacking atmospheres, these can be used to calibrate for stellar variations in the atmospheric exploration of other planets in the system. In cases where the inner planets have atmospheres, monitoring of the full stellar rotation curve is required. This plan realizes the unique benefits of observing multiple simultaneous transits and the coordination of joint space- and ground-based programs to maximize the science return for these unique systems. (read the Nature Astronomy perspective by the Trappist-1 Community Initiative)

(July 2024) The SPECULOOS team, including Adam Burgasser and Cool Star Lab aluma Aishwarya Iyer, have conducted a comprehensive reanalysis of the host star of the TRAPPIST-1 system, combining spectral data from the UV to the infrared, including data from JWST. The analysis provides the best constraints on the temperature, luminosity, and metallicity of this source, and investigated spectral model fits for a heterogenous atmosphere. One of the key conclusions is that even the most advanced spectral models are unable to accurately replicate the spectrum of this important star, motivating the need to improve spectral modeling of low-mass planet host stars. (read the ApJ Letter by Davoudi et al.)

(May 2024) Cool Star Lab members contributed to the discovery of three new Earth-sized planets orbiting M dwarfs. The new planets, TOI-5720 b, TOI-6008 b, and TOI-6086 b all have orbit periods of about 1 day, and so close to their stars that they are too hot to be habitable. CSL member helped characterize the host stars using optical spectroscopy obtained with the Kast spectrograph on Lick Observatory (read the article by Barkaoui et al. in Astronomy & Astrophysics)

(May 2024) Cool Star Lab members Adam Burgasser, Christian Aganze, and Christopher Theissen contributed to the discovery of a new Earth-sized planet orbiting a late-type M dwarf. The planet, named SPECULOOS-3, is on a mere 17-hour orbit around its cool host star, making it too hot to be a habitable world. However, it is one of the best targets to measure dayside emission, which may reveal the geological properties of this terrestrial exoplanet (read the Nature Astronomy paper by Gillon et al. and the UCSD press release).

(April 2024) Adam Burgasser contributed to analysis of the host star of the newly-discovered mini-Neptune exoplanet TOI-4336A b. The star is part of a hierarchical M dwarf triple system with nearly identical masses, mirroring the alien host star system in the Three Body Problem. The planet, which is about twice the size of Earth and receives 50% more light than Earth, is a promising target for transmission spectroscopy of a habitable zone world (read the article by Timmermans et al. in Astronomy & Astrophysics)

(Oct 2023) Adam Burgasser contributed to the analysis of another giant planet orbiting a metal-rich early-M dwarf TOI-4201. The exoplanet, weighing in at 2.5 Jupiter masses and with an orbit period of just 3.6 days, occupies a sparse region in planet mass and separation among M dwarf systems (read the AJ article by Gan et al.). 

(Sep 2023): Adam Burgasser analyzed the optical spectrum of the host star to the newly-discovered giant exoplanet TOI-4860b. The Magellan/MagE spectrum revealed this source to be an inactive, slightly metal-rich M4.5 dwarf, making it the lowest-mass star known to host a giant planet (read the MNRAS article by Triaud et al.).  

(Sep 2023): Cool Star Lab team members helped to characterize the low-mass stellar host to a new Super Earth planet. The star, TOI-1680, was found to be an inactive M4.5, right at the fully convective stellar mass boundary. The planet, TOI-1680b, has a radius about 50% larger than Earth, and is also warmer with a 400 K equilibrium temperature. The relatively bright primary and favorable radius ratio makes this an important new target for atmospheric characterization with JWST (read the A&A article by Ghachoui et al.). 

(Jun 2023): Adam Burgasser and Carl Melis obtained Lick/Kast optical spectra for one of two new low-mass planet host stars identified in TESS + SPECULOOS. The star, TOI-2084, has a previously unrecognized co-moving, low-mass stellar companion 1400 AU away, giving the 6.7 Earth-mass planet a second "dim red bulb" to illuminate it (read the preprint by Barkaoui et al.). 

(May 2023): Adam Burgasser and Christian Aganze helped characterize a new low-mass exoplanet host star TOI-715, an old M4 dwarf that hosts a super-Earth planet in its habitable zone. Adam analyzed optical spectra obtained with Magellen/LDSS-3C, while Christian used GALAH data to statistically constrain the star's age (read the prepint by Dransfield et al.)

(Mar 2023): Cool Star Lab researchers helped characterize the low-mass stellar host of the double-planet system TOI-2096. TESS and ground-based monitoring show that this system contains both a super-Earth and a mini-Neptune orbiting a star less than a quarter the mass of the Sun. The CSL team obtained optical spectroscopy with Kast on the Lick Shane Telescope that determined the host star's spectral type, temperature, and metallicity. (read the paper by Pozuelos et al. at Astronomy & Astrophysics).