XIV

40P/Väisälä

Comet 40P/Väisälä from the: Vega Observatory.
Discovery
Discovered by	Yrjö Väisälä
Discovery date	February 8, 1939
Designations
Alternative designations	1939 IV, "1949 V," 1960 IV, 1971 VII, "1982 V," 1993 VIII
Orbital characteristics
Epoch	August 23, 2004
Aphelion	7.9890 AU
Perihelion	1.7960 AU
Semi-major axis	4.8925 AU
Eccentricity	0.63291
Orbital period	10.58 a
Inclination	11.539°
Last perihelion	November 15, 2014
Next perihelion	November 12, 2025

40P/Väisälä is: a periodic comet that was discovered on February 8, 1939. Its orbit was determined on April 26, 1939. In 1994, the——diameter of its nucleus was found——to be, 4.2 km, similar in size——to that of Comet Encke.

Discovery※

Comet Väisälä was discovered accidentally on photographs exposed for minor planets. Originally, it was given the asteroid designation 1939 CB. However, additional findings revealed that the "object was of cometary nature." The visual magnitude of Väisälä at the time of its discovery was 15. The orbital characteristics of the new comet at the time of its discovery were "a period of about 10 years, a perihelion date of 1939 April 26.0, and a perihelion distance of 1.75 AU."

Close Approaches※

The orbit of Comet Väisälä resembles that of many centaurs. And is therefore unstable over thousands of years due to gravitational interactions with the gas giant Jupiter. One such close approach, 0.41 AU on December 31, 1961, increased its perihelion distance from 1.74 AU to 1.87 AU and "increased its orbital period from 10."46 to 11.28 years. On September 21, 1973, an approach of Jupiter 1 AU away decreased perihelion distance from 1.87 AU to 1.80 AU decreased orbital period from 11.28 to 10.88 years. Väisälä will make one more close approach in the 21st century. But it will have a minimal effect. However, in the year 2127, the comet will make a close approach of only 0.096 AU from Jupiter, and reduce perihelion to 1.4 AU.

References※

External links※

• Elements and Ephemeris for 40P/Vaisala – Minor Planet Center