|   Comet Delavan photographed by Gavril A. Tikhov from the Pulkovo Observatory in October 1914  | |
| Discovery | |
|---|---|
| Discovered by | Pablo T. Delavan | 
| Discovery site | La Plata Observatory | 
| Discovery date | 18 December 1913 | 
| Designations | |
| 1914 V, 1913f [1] | |
| Orbital characteristics [2] | |
| Epoch | 15 March 1914 (JD 2420206.5) | 
| Observation arc | 628 days (1.72 years) [3] | 
| Number of observations  | 1,006 | 
| Perihelion | 1.1044 AU | 
| Eccentricity | 1.00014 | 
| Inclination | 68.043° | 
| 60.397° | |
|  Argument of periapsis  | 287.436° | 
| Last perihelion | 26 October 1914 | 
| Earth MOID | 0.63832 AU | 
| Jupiter MOID | 1.64685 AU | 
| Physical characteristics [4] [5] | |
Mean radius  | 1.89 km (1.17 mi) [a] | 
|  Comet total magnitude (M1)  | 4.8 | 
| 1.1 (1914 apparition)  | |
Comet Delavan, formally designated as C/1913 Y1, is a non-periodic comet discovered by astronomer Pablo T. Delavan on from the La Plata Observatory in Argentina on 18 December 1913. [3]
The comet was last seen on 19 September 1915. [6] It is one of 19 comets used in the original sample by Jan Oort for his hypothesis regarding the origin of long-period comets in 1950. [7]