C/1911 O1 (Brooks)
Comet C1911 O1 (Brooks).jpg
C/1911 O1
Discovered byWilliam Robert Brooks
Discovery dateJuly 21, 1911
1911 V, 1911c, Comet Brooks
Orbital characteristics A
EpochOctober 11, 1911 (JD 2419320.5)
Aphelion~306.9 AU[1]
Perihelion0.489429 AU
Semi-major axis~153.7 AU
Orbital period~1900 yr[1]
Last perihelionOctober 28, 1911
Next perihelionunknown

C/1911 O1 (Brooks), also designated 1911 V or Comet Brooks, was a bright comet discovered in July 1911 by astronomer William Robert Brooks.

It is notable for becoming a bright naked-eye object of second magnitude, with a narrow straight tail of up to thirty degrees in length and a distinct blue colour;[2] this colour seen in some comets is usually a result of the emission of carbon monoxide ions. It was also notable for uniquely being visible at the same time (mid October 1911) and in the same part of the sky as a second bright comet; this was C/1911 S3 (Beljawsky), which reached the first magnitude, had a fifteen degree tail and a bright golden-yellow appearance.[2]

C/1911 O1 (Brooks) shortly before its last perihelion, October 19, 1911.
C/1911 O1 (Brooks) shortly before its last perihelion, October 19, 1911.


  1. ^ a b Horizons output. "Barycentric Osculating Orbital Elements for Comet C/1911 O1 (Brooks)". Retrieved 2011-02-03. (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)
  2. ^ a b Bortle, J. The Bright Comet Chronicles, International Comet Quarterly, 1998