NASA’s Transiting Exoplanet Survey Satellite (TESS) helped astronomers capture a clear image sequence of a natural comet outburst, Comet 46P/Wirtanen. The image was captured by astronomers at the University of Maryland (UMD), in College Park, Maryland. According to NASA, the image captured is the most “complete and detailed observation” of the formation and dissipation of a naturally-occurring comet outburst.
TESS is a space telescope for NASA’s Explorers program and has been designed to look for exoplanets with the help of a transition method. “TESS spends nearly a month at a time imaging one portion of the sky. With no day or night breaks and no atmospheric interference, we have a very uniform, long-duration set of observations. As comets orbit the Sun, they can pass through TESS’ field of view. Wirtanen was a high priority for us because of its close approach in late 2018, so we decided to use its appearance in the TESS images as a test case to see what we could get out of it. We did so and were very surprised,” mentioned Tony Farnham, a research scientist in the UMD Department Of Astronomy.
The animation captured of the Comet 46P/Wirtanen shows an explosive outburst of dust, ice and gases that occurred on September 26, 2018 and got dissipated over the next 20 days. These images captured from NASA’s TESS spacecraft were taken every three hours during the first three days of the outburst.
NASA states that many comets go through occasional spontaneous outbursts that can temporarily increase the comet’s activity. Although the cause for these comet outbursts isn’t currently known, they’re related to the conditions on the comet’s surface. It further added that studies of the outburst behavior in the early brightening stages are difficult to capture and can give insight into the physical and thermal properties of the comet. TESS also managed to capture Wirtanen’s dust trail for the first time.
“With 20 days’ worth of very frequent images, we were able to assess changes in brightness very easily. That’s what TESS was designed for, to perform its primary job as an exoplanet surveyor. We can’t predict when comet outbursts will happen. But even if we somehow had the opportunity to schedule these observations, we couldn’t have done any better in terms of timing. The outburst happened mere days after the observations started,” states NASA.
The current discovery describes initial results and the team looks forward to further analysis of Wirtanen along with other comets that are in TESS’s field-of-view.