Planet Hunters TESS II: findings from the first two years of TESS

Abstract

We present the results from the first two years of the Planet Hunters TESS (PHT) citizen science project, which identifies planet candidates in the TESS (Transiting Exoplanet Survey Satellite) data by engaging members of the general public. Over 22 000 citizen scientists from around the world visually inspected the first 26 sectors of TESS data in order to help identify transit-like signals. We use a clustering algorithm to combine these classifications into a ranked list of events for each sector, the top 500 of which are then visually vetted by the science team. We assess the detection efficiency of this methodology by comparing our results to the list of TESS Objects of Interest (TOIs) and show that we recover 85 per cent of the TOIs with radii greater than 4 R⊕ and 51 per cent of those with radii between 3 and 4 R⊕. Additionally, we present our 90 most promising planet candidates that had not previously been identified by other teams, 73 of which exhibit only a single-transit event in the TESS light curve, and outline our efforts to follow these candidates up using ground-based observatories. Finally, we present noteworthy stellar systems that were identified through the Planet Hunters TESS project.

pyaneti II: A multidimensional Gaussian process approach to analysing spectroscopic time-series

“…Fortunately, they can be detected by methods that do not rely on periodicity of transit-like events (see e.g. Eisner et al 2021;Osborn et al 2016).…”

“…The scaled semi-major axis is a dummy value sampled to take into account the transit shape, while the orbital period is a derived parameter, i.e., we do not sample for it directly, we compute it with the other sampled parameters assuming the orbit is circular. This capability of the code has been used before to estimate periods for transit signals detected by the TESS mission (e.g., Eisner et al 2021).…”

“…This new version also allows one to model multi-band transits and single transit events, and features various performance improvements. This new version of pyaneti has already been used in recent exoplanet characterisation works (e.g., Carleo et al 2020;Eisner et al 2021Eisner et al , 2020Georgieva et al 2021).…”

The Number of Transits Per Epoch for Transiting Misaligned Circumbinary Planets

“…Transit flagging is possible through visual inspection (e.g. Eisner et al 2021) or automated detection, even in the case of arbitrarily shaped dips Wheeler & Kipping (2019), and the number of transits per epoch would simply be the temporal clusterings of these events. Thus, we expect that the number of dips occurring in each epoch is a readily observable quantity, available without significant photodynamical analysis (e.g.…”

“…Individual transits are demonstrably discoverable either by citizen scientists (e.g. Eisner et al 2021) or an automated routine sensitive to single events of potentially highly peculiar shape (such as the "weird detector" algorithm; Wheeler & Kipping 2019). This work seeks to build some intuition and understanding of how these sequences would appear in our data, and how they could be ultimately used to make progress in the detection and interpretation of a misaligned circumbinary population.…”