Connections between the jet activity and surface features on Comet 9P/Tempel 1

We present results from our study of the Stardust-NExT NAVCAM images of Comet 9P/Tempel 1, in which we analyze the dust coma and derive the locations and directions of 11 isolated jets detected around closest approach. Seven of the jets form a cluster that is associated with terraced terrain near the equator. Other jets arise from the nightside of the nucleus, having been in darkness for as long as 4 h, indicating that thermal lags continue to drive activity long after sunset. We compare the coma features observed here to those seen during the Deep Impact encounter on the previous apparition, and argue that much of the isolated jet activity is associated with steep slopes and the edges of smooth areas. We estimate that the cluster of jets produces 7–20% of the total dust in the coma, indicating that isolated sources play a significant role in the comet’s activity. We measured an average dust production rate A(α)fρ = 42 ± 6 cm at an approach phase angle of 79°, corresponding to a dust mass loss of approximately 264 kg s−1. Our analysis also indicates that the Stardust-NExT spacecraft did not pass through any dust jets during the flyby.

► A cluster of jets in comet Tempel 1 arise from a terraced region on the surface.
► Jets, covering <0.25% of the surface, produce up to 20% of the total dust.
► Cometary activity preferentially arises from slopes and edges of surface features.
► Jet activity arises from unilluminated areas, suggesting long thermal lags.
► Average dust production during the Stardust-NExT encounter was 264 kg sec−1.