ExoEarth yield landscape for future direct imaging space telescopes

Christopher C. Stark; Rus Belikov; Matthew R. Bolcar; Eric Cady; Brendan P. Crill; Steve Ertel; Tyler Groff; Sergi Hildebrandt; John Krist; P. Douglas Lisman; Johan Mazoyer; Bertrand Mennesson; Bijan Nemati; Laurent Pueyo; Bernard J. Rauscher; A. J. Riggs; Garreth Ruane; Stuart B. Shaklan; Dan Sirbu; Rémi Soummer; Kathryn St. Laurent; Neil Zimmerman

doi:10.1117/1.JATIS.5.2.024009

20 May 2019 ExoEarth yield landscape for future direct imaging space telescopes

Christopher C. Stark, Rus Belikov, Matthew R. Bolcar, Eric Cady, Brendan P. Crill, Steve Ertel, Tyler Groff, Sergi Hildebrandt, John Krist, P. Douglas Lisman, Johan Mazoyer, Bertrand Mennesson, Bijan Nemati, Laurent Pueyo, Bernard J. Rauscher, A. J. Riggs, Garreth Ruane, Stuart B. Shaklan, Dan Sirbu, Rémi Soummer, Kathryn St. Laurent, Neil Zimmerman

Author Affiliations +

Journal of Astronomical Telescopes, Instruments, and Systems, Vol. 5, Issue 2, 024009 (May 2019). https://doi.org/10.1117/1.JATIS.5.2.024009

Abstract

The expected yield of potentially Earth-like planets is a useful metric for designing future exoplanet-imaging missions. Recent yield studies of direct-imaging missions have focused primarily on yield methods and trade studies using “toy” models of missions. Here, we increase the fidelity of these calculations substantially, adopting more realistic exoplanet demographics as input, an improved target list, and a realistic distribution of exozodi levels. Most importantly, we define standardized inputs for instrument simulations, use these standards to directly compare the performance of realistic instrument designs, include the sensitivity of coronagraph contrast to stellar diameter, and adopt engineering-based throughputs and detector parameters. We apply these new high-fidelity yield models to study several critical design trades: monolithic versus segmented primary mirrors (PMs), on-axis versus off-axis secondary mirrors, and coronagraphs versus starshades. We show that as long as the gap size between segments is sufficiently small (<0.1 % of telescope diameter), there is no difference in yield for coronagraph-based missions with monolithic off-axis telescopes and segmented off-axis telescopes, assuming that the requisite engineering constraints imposed by the coronagraph can be met in both scenarios. We show that there is currently a factor of ∼2 yield penalty for coronagraph-based missions with on-axis telescopes compared to off-axis telescopes, and note that there is room for improvement in coronagraph designs for on-axis telescopes. We also reproduce previous results in higher fidelity, showing that the yields of coronagraph-based missions continue to increase with aperture size while the yields of starshade-based missions turnover at large apertures if refueling is not possible. Finally, we provide absolute yield numbers with uncertainties that include all major sources of astrophysical noise to guide future mission design.

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Christopher C. Stark, Rus Belikov, Matthew R. Bolcar, Eric Cady, Brendan P. Crill, Steve Ertel, Tyler Groff, Sergi Hildebrandt, John Krist, P. Douglas Lisman, Johan Mazoyer, Bertrand Mennesson, Bijan Nemati, Laurent Pueyo, Bernard J. Rauscher, A. J. Riggs, Garreth Ruane, Stuart B. Shaklan, Dan Sirbu, Rémi Soummer, Kathryn St. Laurent, and Neil Zimmerman "ExoEarth yield landscape for future direct imaging space telescopes," Journal of Astronomical Telescopes, Instruments, and Systems 5(2), 024009 (20 May 2019). https://doi.org/10.1117/1.JATIS.5.2.024009

Received: 2 October 2018; Accepted: 23 April 2019; Published: 20 May 2019

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