35P/Herschel–Rigollet is a Halley-type comet with an orbital period of 155 years and an orbital inclination of 64 degrees. It was first discovered by Caroline Herschel on 21 December 1788. Given that the comet has a 155-year orbit involving asymmetric outgassing, and astrometric observations in 1939 were not as precise as modern observations, predictions for the next perihelion passage in 2092 vary by about a month.
Caroline Lucretia Herschel (/ˈhɜːrʃəl, ˈhɛərʃəl/ HUR-shəl, HAIR-shəl, German: [kaʁoˈliːnə ˈhɛʁʃl̩]; 16 March 1750 – 9 January 1848) was a German astronomer, whose most significant contributions to astronomy were the discoveries of several comets, including the periodic comet 35P/Herschel–Rigollet, which bears her name. She was the younger sister of astronomer William Herschel, with whom she worked throughout her career.
She was the first woman to receive a salary as a scientist and the first woman in England to hold a government position. She was also the first woman to publish scientific findings in the Philosophical Transactions of the Royal Society, to be awarded a Gold Medal of the Royal Astronomical Society (1828), and to be named an honorary Member of the Royal Astronomical Society (1835, with Mary Somerville). She was named an honorary member of the Royal Irish Academy (1838). The King of Prussia presented her with a Gold Medal for Science on the occasion of her 96th birthday (1846).