Case 2: LUVOIR B, metric A
LUVOIR B uses the coronagraph instrument for detections for the blind search, for orbit determination, and for spectral characterization. The spectral characterization is limited to 20% bandwidth and is accordingly performed in serial to achieve an aggregate spectrum. The solar keepout constraints are generous with solar keepout angles at 90 degrees for typical observations and 45 degrees for high value observations, such as characterizations. The importance of observation scheduling for the coronagraphonly mission is not in the solar keepout constraints but in determining the revisit cadence for detection and the revisit cadence for orbit determination. The observation scheduling exposes the inefficiency of the blind search with the coronagraph under realistic mission scheduling constraints.
The LUVOIR B nominal observing scenario allocates 6 months for full spectra characterization and 2 years for the coronagraph blind search and initial characterization with metric A, water line detection at 940 nm. The EXOSIMS results presented here use 50% of the 5 year mission time, or 2.5 years, for the coronagraph blind search and characterization of targets at the water line. The 2.5 years, instead of 2 years, was used to facilitate comparison with the HabEx architectures and the other metrics which were evaluated for 2.5 years of total mission time.
Dynamic Detection and Characterization Plots
These plots show several quantities relating to detection and characterization in distance/luminosity coordinates. Each star in the target list is represented by one dot in the plot, shaded according to the selected quantity. Some stars in the target list are not observable by the instrument due to SNR limitations, and they are shown in gray.
Hovering over the dot drills down to the target name with exact numerical values and uncertainties. All quantities shown by shading are averages across the runs in the ensemble, and the indicated standard deviation is the standard deviation across the ensemble. This standard deviation captures the inherent variability of the quantity due to the random simulated universe and observational scheduling, if applicable. For instance, the number of exoearths per star is approximately 0.24, and thus the variance of the underlying Poisson count of exoearths is also 0.24, for a typical standard deviation of 0.49. The popup also shows the standard error of the given average, which is the above standard deviation divided by the square root of the ensemble size. This “standard error of the mean” is the error in the given average due to Monte Carlo sampling.
Interactive Detection Plot Widget
Interactive Characterization Plot Widget
PNG static plots

A histogram showing the average, across the ensemble, of the number of exoearths successfully characterized. The bars sum to one.

A timebased plot showing the observing timeline – detections, taking of spectra, slews, and other nonexoplanet observations – from a single representative mission. Slews are shown in narrow gray bars along with taking of spectra. In all timelines, alternating dark and light colors are a visual aid to separate events which are sometimes closely spaced. Integration windows shorter than one day have been enlarged to one day to ensure they are visible in the plot. more

(will write caption if included). Timeline: Keepout Overlaid with Observations Showing Characterization Targets and Keepout Detections: Blue; Characterizations: Green; Obscured: Gray Mission Observation and Keepout Timeline for 229154300: Year 1

Histogram of the average number of events related to observations: detections, characterizations, and detections resulting in target promotion. The values for each sum to one when added across the event count on the abscissa.

Time spent in different modes (detection, characterization, slew), cumulatively as a function of mission elapsed time. Detection time can overlap slew time. Standard deviation across the ensemble is illustrated by the plot bars.

The average number of exoearths characterized versus time, as a cumulative total up to the given time. One value is plotted for each month of mission elapsed time. The error bars are at plus and minus one standard deviation, again computed across the ensemble. The line for all characterizations is the sum of unique characterizations and revisits.

The average number of exoearths detected versus time, as a cumulative total up to the given time. One value is plotted for each month of mission elapsed time. The error bars are at plus and minus one standard deviation, again computed across the ensemble. The line for all detections is the sum of unique detections and revisits.

The average across the ensemble of the characterization SNR for successful characterizations, separated by 15 mutually exclusive planet types plus exoearths (16 categories total). The measure of variability given by the bars is the 25% and 75% quantiles of observed SNR across the ensemble. All distributions of SNR are truncated below because of the minimum SNR required for characterization. The planet types are as defined in the STDT report following Kopparapu et al., ApJ, 2018. more
Full sized PNGs
Histogram of earths characterized back to list
Observation timeline back to list
Keepout for chars back to list
Event count, dets and chars back to list
Cumulative mission obs back to list
Cumulative Earth chars back to list
Cumulative det earths back to list
SNR demographic back to list