STARRY: Analytic Occultation Light Curves

Luger, Rodrigo; Agol, Eric; Foreman-Mackey, Daniel; Fleming, David P.; Lustig-Yaeger, Jacob; Deitrick, Russell (2019). STARRY: Analytic Occultation Light Curves. The astronomical journal, 157(2), p. 64. American Astronomical Society 10.3847/1538-3881/aae8e5

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We derive analytic, closed form, numerically stable solutions for the total flux received from a spherical planet, moon or star during an occultation if the specific intensity map of the body is expressed as a sum of spherical harmonics. Our expressions are valid to arbitrary degree and may be computed recursively for speed. The formalism we develop here applies to the computation of stellar transit light curves, planetary secondary eclipse light curves, and planet-planet/planet-moon occultation light curves, as well as thermal (rotational) phase curves. In this paper we also introduce STARRY, an open-source package written in C++ and wrapped in Python that computes these light curves. The algorithm in STARRY is six orders of magnitude faster than direct numerical integration and several orders of magnitude more precise. STARRY also computes analytic derivatives of the light curves with respect to all input parameters for use in gradient-based optimization and inference, such as Hamiltonian Monte Carlo (HMC), allowing users to quickly and efficiently fit observed light curves to infer properties of a celestial body's surface map.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Center for Space and Habitability (CSH)
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Deitrick, Russell

Subjects:

500 Science
500 Science > 520 Astronomy
500 Science > 530 Physics

ISSN:

0004-6256

Publisher:

American Astronomical Society

Language:

English

Submitter:

Danielle Zemp

Date Deposited:

14 Apr 2020 12:15

Last Modified:

14 Apr 2020 12:22

Publisher DOI:

10.3847/1538-3881/aae8e5

ArXiv ID:

1810.06559v1

BORIS DOI:

10.7892/boris.142647

URI:

https://boris.unibe.ch/id/eprint/142647

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