C/1729 P1 (Sarabat) - unlucky comet of the millennium
A comet that is very much overlooked because it was by no means a spectacular visual sight , nor was it a comet with great brightness or a tail that tore the very heavens asunder, but is an object that has always perplexed me and ignited my imagination since the days of C/1995 O1 (Hale-Bopp) for one reason, its sheer size and what could have been great potential had circumstances prevailed.
Discovery
The comet was discovered on the morning of August 1st,1729 by Father Nicolas Saarabat,a French mathematician, scientist and Jesuit priest,by naked eye at a magnitude of +5 .
The comet was located in the constellation of Equuleus, and appeared visually as a, "faint ,nebulous star", which Saarabat initially believed to be a part of the Milky Way.
The discoverer
Nicolas Saarabat was the son of the French painter Daniel Saarabat and nephew of the engraver, Isaac Saarabat and was born on February 7th,1698 in Lyon,France.
The family were of the Protestant religion originally and acquired a wealth from making clocks and watches, later Daniel Saarabat converted to Catholicism ,
Nicolas had a varied scientific interest in subjects such as astronomy, magnetism wind patterns and immersing roots of living plants in the red juice of Phytolacca berries in order to observe circulation.
Saarabat died whilst on a trip to Paris in 1739 while seeking treatment for a liver complaint.
An unusual comet
Moonlight had hindered observations of the comet from August 2nd and the next chance to view it came on August 9th, and Saarabat was to confirm that the object was indeed a comet.
Word soon reached Jaques Cassini (18/02/1677-16/04/1756) , French astronomer and son of famous Italian astronomer Giovanni Cassini in Paris and he noted the position of the comet and was surprised to see that the comet had hardly moved since its discovery a month before.
On August 26th, Cassini noted that the comet was 1.5' in diameter and near magnitude 3.5.
A little trivia ,It is Cassini who is responsible for the wrong spelling of the comet in official designation, he wrote "Sarabat" instead of Saarabat.
English astronomer John Russell Hind was the first to calculate the orbit and determined that perihelion was on June 16th,1729 at a distance of 4.05 AU, just inside the perihelia distance of Jupiter .
Orbital Characteristics.
Epoch= 16/06/1729
q=4.05054 au
e=1 (assumed)
i= 77.095 degrees.
Discovery distance from Earth=3.125 au, (also closest approach to Earth.)
Distance of last observation from Earth=5.140 au. (mag 8)
Distance comet travelled in sky during 6 months of observations= 15 degrees.
Earth-comet distance, April 20th,2015 = 237.326 AU.
Monster comet?
The formulae I use to determine actual coma size means that , using Cassini's estimation of a coma 1.5 arcmins in size, indicates the comet was around 825,710 km in diameter, but what is more interesting is that C/1729 P1 (Sarabat) had an absolute magnitude of around -3 which indicates a very large nucleus.
By comparison, the "Great" comet C/1995 O1 (Hale-Bopp) , the largest known comet to enter the inner Solar System at around 60km in diameter,had an absolute magnitude of -1.
Saarabat most likely had a nucleus size much akin to the grandparent of the Kreutz group of Sungrazers before it split up aeons ago of around 100km.
One can only imagine or dream of what a comet like C/1729 P1 would look like with a perihelion distance of say, 0.5 or 0.3 au's.
Would this comet been then the "Comet of the Millennium"?
I wonder.....
Neil Norman, Ipswich, England