Date: Monday 10-Feb-2025
Speaker: Rob Zellem (NASA GSFC)
Title: The Nancy Grace Roman Space Telescope: NASA’s Next Astrophysics Flagship Mission
Abstract: The Nancy Grace Roman Space Telescope is NASA’s next astrophysics flagship mission launching no earlier than October 2026 and no later than May 2027 to conduct transformative infrared astronomy, study cosmology by the structure and evolution of the universe, and to discover and observe exoplanets. Roman will perform visible to infrared photometry and spectroscopic observations with its primary instrument, the Wide Field Instrument. These observations are currently being defined by the larger astronomy community via its Core Community Surveys. Roman’s secondary instrument, the Coronagraph, will serve as a technology demonstration of ground-based direct imaging technology and techniques for the first time ever in space. The lessons learned from the Roman Coronagraph will directly inform the development of NASA’s Habitable Worlds Observatory, the next astrophysics flagship after Roman launching in ~15 years that is being designed to search for life on other words. Rob will give an overview of Roman, current mission status, and ways to get involved in this community-driven space observatory.
Date: Monday 24-Feb-2025
Speaker: William DeRocco (University of Maryland)
Title: Free-floating planets in the era of Roman
Abstract: The Roman Space Telescope's Galactic Bulge Time Domain Survey will provide a new window into the demographics of free-floating planets, planets unbound to any star. The mass and velocity distributions of this population hold key insights into their formation mechanisms and the growth of planetary systems in a short-lived period of early dynamical instability that is otherwise difficult to probe observationally. In this talk, I will show the results of the first simulation-based prediction for the Galactic free-floating planet mass function and connect these results to particular features in the mass function that Roman will be able to observe.
Date: Monday 10-Mar-2025
Speaker: Hannah Diamond-Lowe (STScI)
Title: TBD
Abstract: TBD
Date: Monday 24-Mar-2025
Speaker: Zafar Rustamkulov (Johns Hopkins University)
Title: The Transit Age: Planetary Atmospheres, Interiors, and Parent Stars in the Era of JWST
Abstract: JWST observations continue to shine inspiring new insights into the nature of planetary systems across a vast demographic landscape. In this talk, I'll show how these infrared time series data access planetary climates, interiors, orbits, and their coupled evolution. I will share a handful of spectroscopic results, from the largest/hottest planet occulting a blue subgiant, to the smallest/coldest planet transiting a red dwarf. I will demonstrate how these stellar exoplanet datasets can be assembled to characterize the parent star to an unprecedented degree, yielding state-of-the-art age constraints for nearly a dozen giant planet systems thus far. Lastly, I'll zoom out and synthesize how atmospheric spectra, ages, and refined stellar characteristics will help us understand the diverse and evolving inner lives of giant planets over the coming decade.
Date: Monday 31-Mar-2025
Speaker: Sierra Ferguson (Southwest Research Institute)
Title: TBD
Abstract: TBD
Date: Monday 07-Apr-2025
Speaker: Amy Tuson (NASA GSFC / UMBC)
Title: Long-Period Exoplanets and Solar System Asteroids with TESS
Abstract: In this seminar, I will present two projects that capitalise on the unique observing strategy of the Transiting Exoplanet Survey Satellite (TESS).
Firstly, due to its 27d observing baseline, TESS is biased towards the discovery of short-period exoplanets. To increase the yield of long-period exoplanets (≳ 20d), I use TESS "duotransits". These are planet candidates with two observed transits separated by a large gap, meaning follow-up observations are required to determine their orbital period. I created a specialised pipeline to discover TESS “duotransits”, which I then follow-up with the CHaracterising ExOPlanet Satellite (CHEOPS). I will present my pipeline, its new discoveries and the sample of 20 small, long-period planets uncovered by TESS and CHEOPS, including the Neptune-mass planet TOI-5678 b and the bright multi-planet system HD 15906.
Secondly, due to its all-sky nature, TESS is observing thousands of solar system asteroids. This offers the unique opportunity to homogeneously study a large sample of asteroids and improve our knowledge of their rotation period distribution and binary fraction. To facilitate this endeavor, I have developed “tess-asteroids” – a flexible, open-source Python package that creates Target Pixel Files (TPFs) and Light Curve Files (LCFs) for asteroids observed by TESS. I will present this package, some example TPFs and LCFs for bright asteroids (V < 19) observed during TESS sectors 1 to 3 and a first look at their rotation periods.
Date: Monday 14-Apr-2025
Speaker: Michelle Thompson (Purdue University)
Title: TBD
Abstract: TBD
Date: Monday 21-Apr-2025
Speaker: Megan Weiner Mansfield (University of Maryland)
Title: Searching for atmospheres on rocky M-dwarf planets with JWST
Abstract: One of the most exciting opportunities enabled by JWST is the characterization of atmospheres on terrestrial planets orbiting M Dwarfs (M-Earths). However, transmission spectroscopy of M-Earths with JWST has been ambiguous due to challenges such as stellar contamination. I will describe the technique of using thermal emission to search for atmospheres on M-Earths and present several new observations of M-Earths in thermal emission with JWST/MIRI+LRS. These observations overall show hot daysides which firmly rule out the presence of thick, Venus-like atmospheres. However, when combined with other JWST M-Earth results, they show a tentative trend in measured brightness temperature as a function of instellation, with less irradiated planets generally less consistent with dark and bare rocks. I will discuss potential hypotheses that could explain this trend and the prospects for using the ongoing Rocky Worlds DDT program to differentiate between them.
Date: Monday 21-Apr-2025
Speaker: Natalie Allen (Johns Hopkins University)
Title: Towards the detection of terrestrial atmospheres with JWST
Abstract: JWST is enabling the characterization of exoplanet atmospheres like never before. While we are making revolutionary advances in the understanding of giant planet atmospheres, we still have not definitively detected the atmosphere of a terrestrial exoplanet. One of the major roadblocks towards detection has been the effect of stellar contamination, or contamination due to active regions on the stellar surface. I will discuss efforts towards detecting terrestrial atmospheres in emission, dodging the problem of stellar contamination, through the Hot Rocks Survey, with an eye towards the 500-hour JWST DDT Rocky Worlds program. I will also present efforts to detect an atmosphere on TRAPPIST-1 e in transmission in spite of large stellar contamination signals. With the same approximate size and equilibrium temperature as Earth, TRAPPIST-1 e is the most “Earthlike” planet currently available for characterization. I will discuss the results from the TST-DREAMS GTO program, and then present the first observations from our large follow-up GO program attempting to detect an Earthlike atmosphere around TRAPPIST-1 e using TRAPPIST-1 b as a stellar contamination proxy.
Date: Monday 28-Apr-2025
Speaker: Andy Lopez-Oquendo (NASA GSFC)
Title: TBD
Abstract: TBD
Date: Monday 05-May-2025
Speaker: Matthew Belyakov (CalTech)
Title: TBD
Abstract: TBD
