Predictions of the LSST Solar System (non-)Yield

Abstract

We present predictions for solar system objects the Vera C.\ Rubin Observatory Legacy Survey of Space and Time (LSST) will not detect over its ten-year baseline survey. Employing state-of-the-art synthetic population models and the \texttt{Sorcha} survey simulator, we identify non-yield populations spanning geometric, photometric, kinematic, temporal, and computational failure modes. Notable subpopulations include objects whose peak brightness coincides exclusively with scheduled telescope downtime, objects whose detections fall within Rubin focal plane chip gaps, and objects whose orbital arcs expire before linking jobs are dispatched from the compute queue. We additionally characterise the non-yield arising from the Death Star (DS-1; $D \approx 160$~km), whose orbital mechanics (when constrained by the well-established Endor engagement geometry \citep{lucas83}) place it at a maximum heliocentric distance of $27.5$~au and an apparent magnitude of $m_r \approx 19$-23, squarely within the LSST operational photometric window. Its absence from the LSST alert stream is interpreted as confirmation of its destruction at the Battle of Endor. The failure to detect the Sun within the LSST should be a stark warning to the community of the LSST's inability to catalogue the solar system (by mass).

Figures (4)

• Figure 1: Orbit configuration of Antichthon as we like to believe Philolaus mind-mapped it. Earth (or, Terra) is on the right, whilst Antichthon is on the left, or counter to Earth. Both orbit anticlockwise around the Sun at the centre. Red lines denote the Lagrange points of the Earth(Terra)-Sun system. Of course, this renders Antichthon unobservable at any stage of Earth's orbit.
• Figure 2: Postage stamp cutouts of comets bayeux_tapestryaugsburg_signs_ed. Clearly visible in both are flames, indicating a level of emissivity not accounted for in modern cometary photometry. White/grey horizontal bars would show the pixel (pigment? stitch?) scale were that known. Images are oriented such that North is up and East is left as shown by green arrows, at least we assume. Marked as a red arrow is the anti-velocity direction, and not marked is the anti-solar direction (comets don't orbit the Sun until the $\sim17^{\mathrm{th}}$ century).
• Figure 3: Apparent $r$-band magnitude of the Death Star (DS-1; $D = 160$ km) as a function of heliocentric distance, for geometric albedos $p_v = 0.04$ (orange; $H = 8.1$, characteristic of a carbonaceous surface) and $p_v = 0.96$ (red; $H = 4.6$, characteristic of Eris). The LSST single-visit detection limit ($m_r \sim 24.5$) is shown as a dashed horizontal line. The vertical line marks the relativistic upper bound on the semi-major axis ($a_{\rm max} \approx 27.5$ au) derived from the Endor geosynchronous engagement constraint lucas83. Planet positions along the x-axis are shown for scale. At $a_{\rm max}$, the Death Star falls within the LSST photometric window for all physically reasonable albedo assumptions, yet is undetected. The preferred interpretation is its destruction. The alternative is left as an exercise for the reader's threat model.
• Figure 4: Example observations of objects that only align with chip gaps within the LSSTCam footprint. Red dashed lines represent their orbit path, and black crosses are their observations. The right panel represents a rare case of 'snakes and ladders' class object that should be paid no mind.