Habitable Worlds 2021 Workshop Open Engagement Abstracts # Title Abstract Authors 8 Rocky Worlds and We live in a system with multiple rocky planets, but only Earth hosts intelligent life. How did Earth L. Weiss; their Siblings and Venus become twice as large as Mercury and Mars? Did Jupiter help or hinder the growth of the terrestrial planets? Multi-planet systems are natural laboratories that will help us answer these Institute for Astronomy, questions. I am leading a NASA Key Strategic Mission Support Survey to measure the composition University of Hawai'i at diversity in a magnitude-limited sample of multi-planet systems. I will discuss my team's recent Manoa, Honolulu, HI mass measurements, including characterizations of rocky planets and discoveries of distant Jovian companions, and highlight future opportunities for characterizing rocky planets and their siblings. 9 How Stellar Flares Stellar flares have been observed to produce powerful bursts of radiation over a wide range of C. Dong [1], M. Jin [2], M. and Storms Regulate wavelengths, among which X-rays and EUV constitute the major ionizing stellar radiation for Lingam [3,4], K. France [5], J. Atmospheric Losses planetary atmospheres at low and high altitudes, respectively. Stellar flares are considered an Green [6]; from the TRAPPIST-1 impediment to habitability, especially in the case of close-in exoplanets around M-dwarfs since Planets some of these stars are highly active. At the same time, there has been a growing awareness that 1 Princeton University, coronal mass ejections (CMEs) - sometimes termed as stellar storms - associated with stellar flares Princeton, NJ, pose severe threats to planetary atmospheric retention. It is evident that understanding 2 Lockheed Martin Solar and atmospheric escape is vital from the standpoint of habitability since atmospheric evolution Astrophysics Lab (LMSAL), influences the climate and the fluxes of ionizing radiation reaching the surface, among other Palo Alto, CA, factors. Until now, there have been no systematic studies of the impact of stellar flares and 3 Florida Institute of concomitant stellar storms on exoplanetary atmospheric losses despite their indubitable occurrence Technology, Melbourne, FL, and pertinence. Here, we carry out sophisticated 3D magnetohydrodynamic (MHD) simulations 4 Harvard-Smithsonian (that includes important photochemistry) to assess how the atmospheric escape rates of the Center for Astrophysics, TRAPPIST-1 planets evolve during 1) a 10^33 erg flare (based on observations) without a CME Cambridge, MA, (where the CME may be suppressed or its trajectory may miss the planet), and 2) a 10^33 erg flare 5 University of Colorado, with a CME, where the CME is initialized and modeled according to the flare energy by using a Boulder, CO, stellar wind model. We found that the atmospheric escape rates are enhanced by 1-3 orders of 6 NASA Headquarters, magnitude compared to our previous study that used quiescent stellar wind conditions. For the Washington, DC. outermost TRAPPIST-1h, if such flare-CME events occur at a frequency of ~1 per day, a 1-bar atmosphere will be scavenged on a time scale as low as ~ 100 million years. In contrast, this time scale reduces to ~ 1 million years for the innermost TRAPPIST-1b. This represents the first study where the roles of stellar flares and storms on exoplanetary atmospheric escape for the TRAPPIST-1 planets are clearly elucidated. 10 Exploring Biogenic The discovery of a growing number of exoplanets and even extrasolar systems supports the J. Salcedo; Dispersion Inside scientific consensus that it is possible to find other signs of life in the universe. The present work Star Clusters with proposes an explicit mechanism inspired by the dynamics of biological dispersion, widely used in Ciinas Corp, La Calera, ecology and epidemiology, to study the dispersion of biogenic units, interpreted as complex organic COLOMBIA. System Dynamic molecules, between rocky or water exoplanets (habitats) located inside star clusters. The results of Modeling the dynamic simulation suggest that for clusters with populations lower than 4 M⊕/ly3 it is not possible to obtain biogenic worlds after 5 Gyr. Above this population size, biogenic dispersion seems to follow a power law, the larger the density of worlds lesser will be the impact rate (β-0.46) value to obtain at least one viable biogenic Carrier habitat after 5 Gyr. Finally, when we investigate scenarios by varying β, a well-defined set of density intervals can be defined in accordance to its characteristic β value, suggesting that biogenic dispersion has a behavior of “minimal infective dose” of “minimal biogenic effective” events by interval i.e. once this dose has been achieved, doesn’t matter if additional biogenic impact events occur on the habitat. 11 Dynamical and As discoveries of multiple planets in the habitable zone of their parent star mount, developing D. Veras [1], D. Armstrong Biological analytical techniques to quantify extrasolar intra-system panspermia will become increasingly [1], J. A. Blake [1], J. Panspermia important. Here, we provide user-friendly prescriptions that describe the asteroid impact Gutierrez-Marcos [1], A. P. Constraints Within characteristics which would be necessary to transport life both inwards and outwards within these Jackson [2], H. Schäefer [1]; Multiplanet systems within a single framework. Our focus is on projectile generation and delivery, and our Exosystems expressions are algebraic, eliminating the need for the solution of differential equations. We derive 1 University of Warwick, a probability distribution function for life-bearing debris to reach a planetary orbit and describe the Coventry, UNITED KINGDOM, survival of microorganisms during planetary ejection, their journey through interplanetary space, 2 Arizona State University, and atmospheric entry. Tempe, AZ. This work is based on the published Astrobiology journal article: Veras et al. (2018, Astrobiology, Volume 18, Issue 9, pp.1106-1122) For example, this figure illustrates how the kick direction from the panspermia-generated collision affects the inclination of the ejecta orbit. This figure illustrates the probability of life-bearing ejecta intersecting the orbits of the planets in the TRAPPIST-1 system 13 Origins of Kepler- Highly eccentric orbits are one of the major surprises of exoplanets relative to the Solar System, and I. Angelo [1], E. Petigura [1], 1656b's Extreme are typically indicative of a rich dynamical history. One system of particular interest is Kepler-1656, S. Naoz [1], M. MacDougall Eccentricity which hosts a single known planet on a close-in, highly eccentric (e=0.8) orbit. This orbital [1], A. Stephan [2]; configuration places Kepler-1656b on the extreme upper envelope of the e-a diagram and is not a typical outcome of planet formation. Instead, planets formed in a near-circular orbit can be driven 1 University of California, Los to much higher eccentricities via pathways such as planet-planet scattering, perturbation from a Angeles, Los Angeles, CA, stellar flyby, or Kozai evolution induced by an outer stellar or planetary companion in the system. 2 The Ohio State University, To investigate the possibility of these scenarios, we use Gaia, radial velocities, and ground-based Columbus, OH. imaging data to place observational constraints on the properties of a potential companion or flyby perturber to Kepler-1656b. We then model the secular evolution of the system in the presence of a third, outer planet using dynamical simulations to assess the likelihood of a high eccentricity excited via the Eccentric Kozai-Lidov effect. 14 EUV Spectroscopy The long-term stability of exoplanetary atmospheres depends critically on the extreme-ultraviolet K. France [1], B. Fleming[1], with the ESCAPE (EUV) flux from the host star. The EUV flux likely drives the demographics of the short-period planet A. Youngblood [1], J. Mason Mission: Exploring population as well the ability for rocky planets to maintain habitable environments long enough for [1], J. Drake[2], ESCAPE the Stellar Drivers of the emergence of life. In this talk, I will present the Extreme-ultraviolet Stellar Characterization for Science Team; Exoplanet Atmospheric Physics and Evolution (ESCAPE) mission, an astrophysics Small Explorer mission Habitability currently in Phase A. ESCAPE employs extreme- and far-ultraviolet spectroscopy (70-1600 1 LASP / University of Angstroms) to characterize the high-energy radiation environment in the habitable zones (HZs) Colorado, Boulder, CO, around nearby stars. ESCAPE provides the first comprehensive study of the stellar EUV 2 Smithsonian Astrophysical environments that control atmospheric mass-loss and determine the habitability of rocky Observatory, Cambridge, MA. exoplanets. ESCAPE will survey over 200 stars, including known planet hosts, to measure EUV irradiance, EUV flare rates, and the characteristics of stellar coronal mass ejections (CMEs). The ESCAPE instrument comprises a grazing incidence telescope feeding four diffraction gratings and photon-counting detector. The science instrument will be assembled and tested in the space hardware facilities at the University of Colorado Boulder (CU) Laboratory for Atmospheric and Space Physics (LASP), and employs the versatile and high-heritage Ball Aerospace BCP-100 spacecraft. Data archives will reside at the Mikulski Archive for Space Telescopes (MAST). 18 Planetary Magnetic Introduction T. Lazio; Fields, Planetary Even early explanations for Earth's magnetic