503.01 — Expanding our Telescope Toolkit: Exo- planet Science Opportunities with SmallSats
Evgenya L. Shkolnik1
1 School of Earth and Space Explorations, Arizona State University (Tempe, Arizona, United States)
New technologies can disrupt the status quo by chal- lenging the current assumptions and opening up new avenues of research. Small satellites, includ- ing CubeSats, have been growing in popularity in many science and technology fields, yet are only now beginning to receive attention as tools for as- trophysics research. When deployed as space-based telescopes, SmallSats enable science experiments not possible with existing or planned large space mis- sions. We trade some capabilities such as mirror size for lower cost and shorter build times for more fre- quent launch opportunities, with two additional and crucial advantages over large, over-subscribed tele- scopes: SmallSats can monitor sources for weeks or months at time, and at wavelengths not accessible from the ground such as the ultraviolet, far-infrared and low-frequency radio. Achieving high-impact astronomical research with SmallSats is becoming increasingly feasible with advances in technologies such as precision pointing and compact sensitive de- tectors. SmallSats may also pair well with the large space- and ground-based telescopes providing com- plementary data to better explain the physical pro- cesses observed. There are many possible exoplanet- focused science cases for SmallSats, several of which are already in development and more ideas yet to be proposed. I will share our experiences devel-
oping the NASA-funded SPARCS (Star-Planet Ac- tivity Research CubeSat) mission as a case study to explore the challenges and opportunities of astro- physics SmallSats.
503.02 — Exoplanet Imaging with ELTs and the TMT’s Planetary Systems Imager
Andy Skemer1
1 Astronomy, UC Santa Cruz (Santa Cruz, California, United States)
The combination of high angular resolution and sen- sitivity will allow ELTs to image hundreds of exo- planets ranging from gas-giants to super-earths and even a handful of rocky planets. I will review the different types of exoplanets that will be observable with ELTs and also discuss how spectroscopy will enable measurements of molecular abundances, T- P profiles, cloud properties, spin rates, accretion, and weather. Finally I will present an overview of the Planetary Systems Imager, the TMT’s multi- wavelength exoplanet imaging platform.
503.03 — The CHEOPS Mission: Launch Imminent for ESA’s Next Exoplanet Mission
Christopher Broeg1; Willy Benz1; Andrea Fortier1;
Thomas Beck1
1 Center for Space and Habitability, Space and planetary sciences, University of Bern (Bern, Switzerland)
The CHaracterising ExOPlanet Satellite (CHEOPS) is a mission jointly led by Switzerland and ESA which was selected in October 2012 as the first S-class mis- sion in the ESA Science Programme. CHEOPS will be the first space observatory dedicated to search for transits of exoplanets by means of ultrahigh preci- sion photometry on bright stars already known to host planets. It will have access to more than 2/3 of the sky and provide the unique capability of de- termining accurate radii for planets of known mass from ground-based spectroscopic surveys. This will allow a first order characterisation of the planets’ in- ternal structure by determination of their mean den- sity, which provides direct insights into their com- position. CHEOPS will also provide precise radii for new planets discovered by the next generation of ground- or space-based transits surveys.
To reach its goals, CHEOPS is designed to measure photometric signals with a precision of 20 ppm in 6 hours integration time on magnitude 9 stars, and 85 ppm in 3 hour integrations on magnitude 12 stars. The CHEOPS payload is a single telescope of 30 cm clear aperture, which has a single CCD focal plane
detector. In Ritchey-Chrétien telescope optical con- figuration it provides a defocussed image of the tar- get star. The main design drivers are related to the compactness of the optical system and to the capa- bility to reject the stray light. The nominal CHEOPS operational orbit is a polar Sun-Synchronous Orbit (SSO) with an altitude of 700 km and a local time of the ascending node (LTAN) of 6 am; the orbit incli- nation is about 98° and the orbital period is 100 min. The nominal mission lifetime is 3.5 years, with a pos- sible extension to 5 years. CHEOPS will launch as auxillary passenger on a Soyuz from Kourou. The launch is imminent with the launch window defined by Arianespace from 15 October to 14 November this year. This talk will review the CHEOPS mission, its scientific goals and mission design. We will dis- cuss the expected performances and also present lat- est analysis of the ground calibration campaign. An overview of the GTO programme will be presented.
503.04 — ARIEL: ESA’s Mission to Study the Nature of Exoplanets
Göran Pilbratt1
1 ESA/ESTEC (Noordwijk, Netherlands)
The ∼4000 exoplanets currently known display a great diversity of physical parameters, and orbit stars with different properties and planetary system ar- chitectures. For most of them we know only either mass or size, or both. However, planetary modelling based on sizes and masses alone suffer from impor- tant degeneracies. To independently measure chem- ical composition is the next challenge. It would en- able improved modelling, which will enhance our understanding of what planets are made of, how planets and planetary systems form, and how plan- ets and their atmospheres evolve to what we observe today.
The Atmospheric Remote-Sensing Infrared Exo- planet Large-survey (ARIEL) mission has been se- lected by ESA as M4 in the Cosmic Vision pro- gramme for a 2028 launch. ARIEL is dedicated to performing measurements of the chemical compo- sition and dynamics of exoplanet atmospheres for a large population (many hundreds) of known diverse preferentially warm and hot transiting planets, en- abling the understanding of the physics and chem- istry of these far away worlds.
The observations will probe atmospheric chem- istry and dynamics, by means of infrared spec- troscopy in three bands (covering 1.1-7.8 um) and visible/NIR photometry in three bands (covering 0.5-1.1 um). All six bands are observed simulta- neously with an off-axis Cassegrain telescope hav-
ing a ∼1.1 × 0.7 m aperture. Both transit and eclipse/occultation spectroscopy will be employed to obtain transmission and emission spectra. The photometry provides thermal and scattering proper- ties and monitors stellar activity.
ARIEL will conduct its observations from a large halo orbit around the Sun-Earth L2 point. ARIEL wants to embrace the general community, by offer- ing open involvement in target selection, and by pro- viding timely public releases of high quality data products at various processing levels throughout the mission.
In this presentation I will provide an overview of all aspects of the mission, describe the current on- going activities in ESA, the ARIEL Consortium, and industry, and the overall schedule.
503.05 — How to Determine Whether M-Dwarf Ter- restrial Planets Possess Atmospheres
Eliza Kempton1; Daniel D. B. Koll2; Megan Mansfield3;
Matej Malik1; Edwin Kite3; Jacob L. Bean3; Dorian Abbot3; Renyu Hu4
1 University of Maryland (College Park, Maryland, United States) 2 MIT (Cambridge, Massachusetts, United States)
3 University of Chicago (Chicago, Illinois, United States) 4 JPL (Pasadena, California, United States)
In the era of TESS, we expect to detect legions of planets for which atmospheric characterization will be possible with JWST. Perhaps the most exciting among these planets are the rocky ones, which up until now have not been accessible to atmospheric studies. Yet small rocky planets will still be challeng- ing targets for JWST, so the question arises of how best to use JWST to make tangible progress toward understanding the atmospheres of terrestrial bodies. We posit that JWST is best suited to distinguish be- tween rocky planets that do and do not possess at- mospheres by photometrically observing their sec- ondary eclipses. The argument is as follows. The dayside temperature of a tidally locked planet will be reduced by the presence of an atmosphere, either because the atmosphere transports heat to the night side of the planet or because atmospheric scatterers such as clouds will increase the planet’s Bond albedo. There is therefore a maximal secondary eclipse depth that is representative of a hot dayside hemisphere with no atmosphere present. We focus on planets or- biting M stars because they are being discovered in large numbers by current facilities, they are within the observational grasp of JWST, and there is con- siderable skepticism as to whether these planets can retain atmospheres at all given the high-energy irra- diation from their host stars.
I will present the results from a multi-institution collaboration investigating the promise and the lim- its of secondary eclipse photometry as a test for can- didate atmospheres on rocky M-dwarf planets. We have developed a suite of general circulation mod- els and radiative-convective atmospheric structure models, and have developed our understanding of rocky planet surface geochemistry, in order to ad- dress this topic. We have focused our efforts on three warm transiting super-Earths that will be ideal tar- gets for secondary eclipse investigations with JWST. We find that JWST can distinguish between planets with and without atmospheres in as little as a one eclipse — a time investment that significantly out- performs phase curves and the more traditional tran- sit spectroscopy techniques.
503.06 — Cold exoplanets with WFIRST: demo- graphics with the microlensing survey, and char- acterization with the coronagraph instrument
Matthew Penny1
1 Physics & Astronomy, Louisiana State University (Baton Rouge, Louisiana, United States)
As outlined by the 2010 Decadal Survey, NASA’s next flagship mission WFIRST will conduct wide- field infrared surveys and demonstrate space-based coronagraphy techniques necessary to directly im- age exoplanets in reflected visible light. We will give an update on the status of the WFIRST mission, fo- cusing on its two major exoplanet goals. Using its wide field instrument (WFI), WFIRST will carry out a large exoplanet microlensing survey toward the Galactic bulge. This survey is designed to statisti- cally explore exoplanet demographics over a wide range of orbital separations (from <∼1 AU to infinity [i.e., free-floating planets]), and five orders of mag- nitude in mass (super-Jupiters down to a few lu- nar masses). These broad statistics will provide vi- tal, and otherwise unobtainable, observational con- straints on the end products of the planet forma- tion process, and on the occurrence rates of low- mass planets in wider orbits than can be probed by radial velocity and transit techniques. Focusing on recent and upcoming results from the WFIRST Mi- crolensing Science Investigation Team, we will de- scribe new estimates of WFIRST’s capabilities to de- tect bound and free-floating planets, the develop- ment of techniques required to measure microlens- ing planet masses, and the results of a data chal- lenge designed to test planet detection and mod- elling techniques on WFIRST-like simulated data. For the coronagraph instrument (CGI) we present a few key highlights of CGI’s predicted capabilities
for characterizing nearby planetary systems via its technology demonstration of extreme contrast coro- nagraphic imaging and spectroscopy in visible light. CGI will demonstrate five main areas that aid fu- ture direct imaging missions such as LUVOIR and HabEX: exquisite wavefront control through a pair of deformable mirrors, suppression of an on-axis star’s diffraction pattern through occulting masks or shaped pupils, the use of photon counting visible de- tectors, and post-processing techniques at high con- trast in space, and high contrast spectroscopy.
503.07 — Radial Velocity Science in the 2020s: The Future of Ground-based EPRV Surveys
Jennifer Burt1
1 Kavli Institute, MIT (Somerville, Massachusetts, United States) The radial velocity community has delivered a va- riety of new and exciting instruments around the globe over the past two years. While many of these facilities began operations during the end of the 2010s, their true science impact will not be felt until the 2020s. Extreme precision radial velocity instru- ments such as ESPRESSO, EXPRES, and Neid will allow for detailed monitoring of our closest stellar neighbors on a scale that has never been seen before. They will obtain mass measurements for many of the smallest transiting planets from missions like TESS, in addition to surveying nearby stars in search of the short period, terrestrial planets that we expect based on the Kepler planet occurrence rates. Meanwhile, near-infrared spectrographs like HPF, SPIRou, and IRD will facilitate searches for planets around the coolest nearby stars, targeting a variety of stellar host that has not previously been surveyed by Doppler fa- cilities. I will discuss the upcoming advancements within these branches of radial velocity science and how they are expected to expand the current bound- aries of exoplanet discovery space.