Extinction in the Coma of Comet 17P/Holmes

Pedro Lacerda, David Jewitt

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
189 Downloads (Pure)


On 2007 October 29, the outbursting comet 17P/Holmes passed within 0.79" of a background star. We recorded the event using optical, narrowband photometry and detect a 3%-4% dip in stellar brightness bracketing the time of closest approach to the comet nucleus. The detected dimming implies an optical depth τ ≈ 0.04 at 1.5" from the nucleus and an optical depth toward the nucleus center τn < 13.3. At the time of our observations, the coma was optically thick only within ρ <~ 0.01" from the nucleus. By combining the measured extinction and the scattered light from the coma, we estimate a dust red albedo ρd=0.006±0.002 at α=16° phase angle. Our measurements place the most stringent constraints on the extinction optical depth of any cometary coma.
Original languageEnglish
Pages (from-to)1-5
JournalThe Astrophysical Journal Letters
Issue numberL2
Publication statusPublished - 26 Oct 2012


  • comets: individual: 17P/Holmes
  • methods: data analysis
  • occultations
  • opacity
  • techniques: photometric


Dive into the research topics of 'Extinction in the Coma of Comet 17P/Holmes'. Together they form a unique fingerprint.

Cite this