C/1909 L1 (Borrelly–Daniel)

C/1909 L1 (Borrelly–Daniel)
Comet Borrelly–Daniel photographed by Max Planck from the Heidelberg Observatory on 9 March 1910
Discovery[1]
Discovered byAlphonse Borrelly
Zaccheus Daniel
Discovery siteMarseille, France
Princeton, USA
Discovery date15–16 June 1909
Designations
1909 I, 1909a[2]
Orbital characteristics[3]
Epoch8 July 1909 (JD 2418495.5)
Observation arc42 days
Number of
observations
29
Aphelion~350 AU
Perihelion0.843 AU
Semi-major axis~175 AU
Eccentricity0.99519
Orbital period~2,320 years
Inclination52.081°
306.88°
Argument of
periapsis
5.000°
Mean anomaly0.014°
Last perihelion5 June 1909
TJupiter0.728
Earth MOID0.171 AU
Jupiter MOID2.861 AU
Physical characteristics[4]
Comet total
magnitude
(M1)
10.9
9.0
(1909 apparition)

Comet Borrelly–Daniel, formally designated as C/1909 L1, is a non-periodic comet that was co-discovered by astronomers, Alphonse Borrelly and Zaccheus Daniel. It was the seventh comet discovery by Borrelly and the third one for Daniel.[a] About two weeks prior to discovery, the comet made its closest approach to Earth at a distance of 0.852 AU (127.5 million km) on 30 May 1909.[4]

Notes

  1. ^ Coincidentally, this comet is also their final comet discovery.[2]

References

  1. ^ R. T. Crawford (1909). "Note on Comet a 1909". Publications of the Astronomical Society of the Pacific. 21 (127): 176. Bibcode:1909PASP...21..176C. doi:10.1086/121916.
  2. ^ a b "Comet Names and Designations". International Comet Quarterly. Retrieved 12 January 2026.
  3. ^ "C/1909 L1 (Borrelly–Daniel) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 12 January 2026.
  4. ^ a b G. W. Kronk (2007). Cometography: A Catalog of Comets. Vol. 3: 1900–1932. Cambridge University Press. pp. 135–137. ISBN 978-0-521-58506-4.