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Post Info TOPIC: Comet C/1945 X1 (du Toit)


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Comet C/1945 X1 (du Toit)

The comet C/1945 X1 (du Toit) was discovered by South Africa astronomer Daniel du Toit at Harvard College Observatory in Bloemfontein shortly after midnight on December 11, 1945. He estimated the comet brightness to be 7 mag. Only four more observations in each of the following four nights were recorded, during which the comet moved quickly towards the sun.
In early January 1946 Leland E. Cunningham calculated from Du Toits observational data a preliminary orbit, according to which the comet at midnight 27/28 December 1945, when the comet had emerged from behind the sun, should have been "a brilliant object to the naked eye." The retrospective search on coronographic recordings showed no signs of the comet. A search for the comet at Cunningham's predicted positions during January 1946 was also unsuccessful.
It is not certain that the comet did not survive its approach towards the sun, or that only its low brightness was the reason why it was not seen again.
The comet reached a maximum brightness of 7 mag.
According to recent research, the comet is probably a fragment of an 'unobserved comet', which appeared in the first years of the 12th century (an orbital period of around 840 years).
The comet probably originated from the splitting up of the 'unobserved comet' into several fragments, each of which gave rise to a new comet, two of which are C/1882 R1 and C/1965 S1 Ikeya-Seki.
C/1945 X1 (du Toit) belongs to the Kreutz comet family, members of this cometary family have orbital elements characterized by a small perihelia distance, retrograde orbit and long orbital periods.

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Title: Was Comet C/1945 X1 (du Toit) a Tiny, SOHO-Like Kreutz Sungrazer?
Author: Zdenek Sekanina, Rainer Kracht

The goal of this investigation is to reinterpret and upgrade the astrometric and other data on comet C/1945 X1, the least prominent among the Kreutz system sungrazers discovered from the ground in the 20th century. The central issue is to appraise the pros and cons of a possibility that this object is --- despite its brightness reported at discovery --- a dwarf Kreutz sungrazer. We confirm Marsden's (1989) conclusion that C/1945 X1 has a common parent with C/1882 R1 and C/1965 S1, in line with the Sekanina-Chodas (2004) scenario of their origin in the framework of the Kreutz system's evolution. We integrate the orbit of C/1882 R1 back to the early 12th century and then forward to around 1945 to determine the nominal direction of the line of apsides and perform a Fourier analysis to get insight into effects of the indirect planetary perturbations. To better understand the nature of C/1945 X1, its orbital motion, fate, and role in the hierarchy of the Kreutz system as well as to attempt detecting the comet's possible terminal outburst shortly after perihelion and answer the question in the title of this investigation, we closely examined the relevant Boyden Observatory logbooks and identified both the photographs with the comet's known images and nearly 20 additional patrol plates, taken both before and after perihelion, on which the comet or traces of its debris will be searched for, once the process of their digitization, currently conducted as part of the Harvard College Observatory's DASCH Project, has been completed and the scanned copies made available to the scientific community.

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