Populations of the Kreutz Sungrazer System in a SOHO Database

TL;DR

This study confirms nine populations within the SOHO Kreutz sungrazers, revealing cascading fragmentation and population distributions through histogram analysis of orbital elements, with implications for comet evolution models.

Contribution

First confirmation of nine populations in SOHO Kreutz sungrazers using a revised dataset and histogram analysis of true longitudes of the ascending node.

Findings

Population I shows two peaks, indicating a side branch similar to Population Pe.

Clusters of objects suggest ongoing cascading fragmentation.

Population ratios and distribution support a contact-binary model of comet structure.

Abstract

Discovery of nine populations in a set of 193 select SOHO Kreutz sungrazers (Sekanina 2021) is confirmed for the first time via a histogram of the true longitudes of the ascending node, constructed for a revised set of 220 select sungrazers imaged exclusively by the SOHO's C2 coronagraph. Marsden's orbits are approximately corrected for effects of the out-of-plane nongravitational force. Population I displays two peaks in the histogram, one presumably belonging to a side branch alike to Population Pe, but with no related naked-eye sungrazer known. Swarms/clusters of objects are commonplace, providing evidence on cascading fragmentation proceeding throughout the orbit. Augmentation to all C2-only SOHO Kreutz comets, aimed at removing deliberate bias against Populations I and Pe, reduces the appearance of Populations Ia and Pre-I to bulges along the slope of the histogram because of the swollen wings of Populations I and Pe, respectively. Populations II through IV change very little or not at all. The high Population I-to-II abundance ratio, of 14:1, may be a product of temporal limitations in fragment release. A drop in the number of fragments toward the ends of the nodal-longitude distribution, especially from Population II to IV, is in line with the contact-binary model.