National Astronomical Observatory of Japan



Subaru Telescope Observes Rapid Changes in a Comet’s Plasma Tail

| Science

Images from a December 2013 observation of the comet C/2013 R1 (Lovejoy) (Note 1) reveal clear details about rapidly changing activity in that comet’s plasma tail. To get this image, astronomers used Subaru Telescope’s wide-field prime-focus Suprime-Cam to zero in on within 0.8 million kilometers of the comet’s plasma tail, resulted in gaining precious knowledge regarding the extreme activity in that tail as the comet neared the Sun. Their results are reported this week in a paper in the March 2015 edition of the Astronomical Journal.

Figure 1
This GIF animation shows changes in the global structure of Comet Lovejoy’s (C/2013 R1) plasma tail. There are three, 2-minute exposures taken in the I-band. The image is aligned so that the nucleus of the comet is at the same position and the tail lies vertically. The time stamp at the bottom right shows the start time of each exposure in Hawai’i time on the morning of December 4, 2013. Bright parts of the sky are shown as black, and dark parts are shown as white, allowing astronomers to see details in the object more clearly. The white tilted grid is a gap between CCD detectors. In the image, the tail narrows with time, especially downstream of the nucleus (which is at the bottom of the image). Moreover, two clumps were detected forming formed at about 0.3 million kilometers from the nucleus. They drifted toward downstream about 20-25 kilometers per second (Figure 2). [Credit: NAOJ]

Their research paper titled “Initial Speed of Knots in the plasma Tail of C/2013 R1 (Lovejoy)” will be published in Astronomical Journal in its March 2015 issue.