English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A sequence of events, dominated by two outbursts and ending with thepreperihelion disintegration of comet C/2017 S3, is examined. The onset timesof the outbursts are determined with high accuracy from the light curve of thenuclear condensation before it disappeared following the second outburst. Whilethe brightness of the condensation was declining precipitously, the totalbrightness continued to grow in the STEREO-A's HI1 images until two days beforeperihelion. The red magnitudes measured in these images refer to a uniformcloud of nuclear fragments, 2200 km^2 in projected area, that began to expandat a rate of 76 m s^(-1) at the time of the second outburst. A tail extension,detected in some STEREO-A images, consisted of dust released far from the Sun.Orbital analysis of the ground-based observations shows that the comet hadarrived from the Oort Cloud in a gravitational orbit. Treating positionalresiduals as offsets of a companion of a split comet, we confirm the existenceof the cloud of radiation-pressure driven millimeter-sized dust grainsemanating from the nucleus during the second outburst. We detect a similar, butcompact and much fainter cloud (or a sizable fluffy dust aggregate fragment)released at the time of the first outburst. --- The debris would make a sphereof 140 m across and its kinetic energy is equivalent to the heat ofcrystallization liberated by 100 tons of amorphous water ice. Ramifications forshort-lived companions of the split comets and for 1I `Oumuamua are discussed.

Preperihelion Outbursts and Disintegration of Comet C/2017 S3 (Pan-STARRS)