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Register a new userLcTools: A Windows-Based Software System for Finding and Recording Signals in Lightcurves from NASA Space Missions
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Since 2009, the Kepler, K2, and TESS missions have produced a vast number of lightcurves for public use. To assist citizen scientists in processing those lightcurves, the LcTools software system was developed. The system provides a set of tools to efficiently search for signals of interest in large sets of lightcurves using automated and manual (visual) techniques. At the heart of the system is a multipurpose lightcurve viewer and signal processor with advanced navigation and display capabilities to facilitate the search for signals. Other applications in the system are available for building lightcurve files in bulk, finding periodic signals automatically, and generating signal reports. This paper describes each application in the system and the methods by which the software can be used to detect and record signals. The software is free and can be obtained from the lead author by request.
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This paper describes the new QuickFind method in LcTools for finding signals and associated TTVs (Transit Timing Variations) in light curves from NASA space missions. QuickFind is adept at finding medium to large sized signals (generally those with S/N ratios above 15) extremely fast, significantly reducing overall processing time for a light curve as compared to the BLS detection method. For example, on the lead authors computer, QuickFind was able to detect both KOI signals for star 10937029 in a 14 quarter Kepler light curve spanning 1,459 days in roughly 2 seconds whereas BLS took about 155 seconds to find both signals making QuickFind in this example about 77 times faster than BLS. This paper focuses on the user interfaces, data processing algorithm, and performance tests for the QuickFind method in LcTools.
A new era of exploration of the low radio frequency Universe from the Moon will soon be underway with landed payload missions facilitated by NASAs Commercial Lunar Payload Services (CLPS) program. CLPS landers are scheduled to deliver two radio science experiments, ROLSES to the nearside and LuSEE to the farside, beginning in 2021. These instruments would be pathfinders for a 10-km diameter interferometric array, FARSIDE, composed of 128 pairs of dipole antennas proposed to be delivered to the lunar surface later in the decade. ROLSES and LuSEE, operating at frequencies from 100 kHz to a few tens of MHz, will investigate the plasma environment above the lunar surface and measure the fidelity of radio spectra on the surface. Both use electrically-short, spiral-tube deployable antennas and radio spectrometers based upon previous flight models. ROLSES will measure the photoelectron sheath density to better understand the charging of the lunar surface via photoionization and impacts from the solar wind, charged dust, and current anthropogenic radio frequency interference. LuSEE will measure the local magnetic field and exo-ionospheric density, interplanetary radio bursts, Jovian and terrestrial natural radio emission, and the galactic synchrotron spectrum. FARSIDE, and its precursor risk-reduction six antenna-node array PRIME, would be the first radio interferometers on the Moon. FARSIDE would break new ground by imaging radio emission from Coronal Mass Ejections (CME) beyond 2 solar radii, monitor auroral radiation from the B-fields of Uranus and Neptune (not observed since Voyager), and detect radio emission from stellar CMEs and the magnetic fields of nearby potentially habitable exoplanets.
We present a framework for the analysis of direct detection planet finding missions using space telescopes. This framework generates simulations of complete missions, with varying populations of planets, to produce ensembles of mission simulations, which are used to calculate distributions of mission science yields. We describe the components of a mission simulation, including the complete description of an arbitrary planetary system, the description of a planet finding instrument, and the modeling of a target system observation. These components are coupled with a decision modeling algorithm, which allows us to automatically generate mission timelines with simple mission rules that lead to an optimized science yield. Along with the details of our implementation of this algorithm, we discuss validation techniques and possible future refinements. We apply this analysis technique to four mission concepts whose common element is a 4m diameter telescope aperture: an internal pupil mapping coronagraph with two different inner working angles, an external occulter, and the THEIA XPC multiple distance occulter. The focus of this study is to determine the ability of each of these designs to achieve one of their most difficult mission goals - the detection and characterization of Earth-like planets in the habitable zone. We find that all four designs are capable of detecting on the order of 5 Earth-like planets within a 5 year mission, even if we assume that only 1 out of every 10 stars has such a planet. The designs do differ significantly in their ability to characterize the planets they find. Along with science yield, we also analyze fuel usage for the two occulter designs, and discuss the strengths and weaknesses of each of the mission concepts.
Instrumentation techniques in the field of direct imaging of exoplanets have greatly advanced over the last two decades. Two of the four NASA-commissioned large concept studies involve a high-contrast instrument for the imaging and spectral characterization of exo-Earths from space: LUVOIR and HabEx. This whitepaper describes the status of 8 optical testbeds in the US and France currently in operation to experimentally validate the necessary technologies to image exo-Earths from space. They explore two complementary axes of research: (i) coronagraph designs and manufacturing and (ii) active wavefront correction methods and technologies. Several instrument architectures are currently being analyzed in parallel to provide more degrees of freedom for designing the future coronagraphic instruments. The necessary level of performance has already been demonstrated in-laboratory for clear off-axis telescopes (HabEx-like) and important efforts are currently in development to reproduce this accomplishment on segmented and/or on-axis telescopes (LUVOIR-like) over the next two years.
Future space-based direct imaging missions are poised to search for biosignatures in the atmospheres of potentially habitable planets orbiting nearby AFGKM stars. Although these missions could conduct a survey of high-priority target stars to detect candidate Earth-like planets, conducting a precursor radial velocity (RV) survey will benefit future direct imaging missions in four ways. First, an RV survey capable of detecting signals as small as 8 cm/s over timescales of a few years could discover potentially habitable Earth-mass planets orbiting dozens of nearby GKM stars accessible to space-based direct imaging. Second, RVs will improve scheduling efficiency by reducing the required number of revisits for orbit determination, and revealing when a planet of interest is most observable. Third, RV observations will reveal the masses of gas and ice giants that could be mistaken for Earth-mass planets, thereby reducing the time spent identifying false positives. Fourth, mass measurements from RVs will provide the surface gravities necessary for interpreting atmospheric spectra and potential biosignatures.
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