Measurements of [Ci] Emission from Comet Hale‐Bopp

Citations Over TimeTop 14% of 2002 papers

Abstract

We present quantitative measurements of cometary [C I] 9850 Å emission obtained during observations of comet Hale-Bopp (C/1995 O1) in 1997 March and April. The observations were carried out using a high-resolution (λ/Δλ ≈ 40,000) Fabry-Pérot/CCD spectrometer at the McMath-Pierce Solar telescope on Kitt Peak. This forbidden line, the carbon analog of [O I] 6300 Å, is emitted in the radiative decay of C(1D) atoms. In the absence of other sources and sinks, [C I] 9850 Å emission can be used as a direct tracer of CO photodissociation in comets. However, in Hale-Bopp's large, dense coma, other processes, such as collisional excitation of ground-state C(3P), dissociative recombination of CO+, and collisional dissociation of CO and CO2 may produce significant amounts of C(1D). The long C(1D) radiative lifetime (~4000 s) makes collisional deexcitation (quenching) the primary loss mechanism in the inner coma. Thus, a detailed, self-consistent global model of collisional and photochemical interactions is necessary to fully account for [C I] 9850 Å emission in comet Hale-Bopp.

Related Papers

• → Three predictions: Comet 67P/Churyumov–Gerasimenko, comet C/2012 K1 PANSTARRS, and comet C/2013 V5 Oukaimeden(2014)3 cited
• Comet Notes: Comet 1945 c (du Toit); Comet 1942 VII (Oterma); Comet 1939 IV (Väisälä); Comet 1948 h (Wirtanen); Comet 1949 a (Johnson); Comet 1916 II (Neujmin 2); Comet 1928 I (Reinmuth I); Comet 1927 VI (Gale); Comet 1925 II (Schwassmann-Wachmann No. 1); Comet 1949 c (Bappu-Bok-Newkirk)(1949)
• Comet 1928 I (Reinmuth I); Comet 1927 VI (Gale); Comet 1948 l; Comet 1948 a (Mrkos); Comet 1939 IV (Väisälä); Comet 1948 i (Ashbrook-Johnson); Comet 1916 II (Neujmin 2); Comet 1948 d (Pajdusakova); Comet 1925 II (Schwassmann-Wachmann No. 1); Comet 1945 c (du Toit)(1949)
• Comet Notes: Comet 1927 g (Schaumasse); Comet 1927 k (Skjellerup); Comet 1927 h (Encke); Comet 1926 f (Comas Solá); Comet 1927 d (Stearns)(1928)
• Comet Notes: Comet 1925 a (Shajn); Comet 1925 b (Reid); Comet 1926 d (Finlay); Comet 1926 c (Kopff); Comet 1922 I (Skjellerup) and 1902 II (Grigg) identical(1927)