IRAS LRS Spectra of Comets Tempel 1 and Tempel 2 (original) (raw)

The infrared spectrum of comet C/1995 O1 (Hale-Bopp) at 4.6 AU from the Sun

Astronomy and Astrophysics, 1996

Comet C/1995 O1 (Hale-Bopp) was observed on 27 April 1996 with the ISOPHOT instrument of ISO when it was at 4.6 AU from the Sun. The 2.5-12μm spectrum was recorded at low resolution. We present here the preliminary results of this observation. The 2.5-5μm spectrum shows emission in the CO_2_ ν_3_ band. The CO_2_ production rate is about 1.3x10^28^ s^-1^. The 6-12μm spectrum shows thermal emission at a colour temperature of 162K (6-8μm range) and a strong silicate band around 10μm, with a narrow feature at 11.2μm indicative of crystalline silicates.

Submitted, 2011-02-28; Accepted, 2011-05-03 Physical Properties of Main-Belt Comet 176P/LINEAR 1

2016

We present a physical characterization of comet 176P/LINEAR, the third member of the new class of main-belt comets, which exhibit cometary activity but are dynamically indistinguishable from main-belt asteroids, to be discovered. Observations show the object exhibiting a fan-shaped tail for at least one month in late 2005, but then becoming inactive in early 2006. During this active period, we measure broadband colors of B − V = 0.63 ± 0.02, V − R = 0.35 ± 0.02, and R − I = 0.31 ± 0.04. Using data from when the object was observed to be inactive, we derive best-fit IAU phase function parameters of H = 15.10 ± 0.05 mag and G = 0.15 ± 0.10, and best-fit linear phase function parameters of m(1, 1, 0) = 15.35 ± 0.05 mag and β = 0.038 ± 0.005 mag deg−1. From this baseline phase function, we find that 176P exhibits a mean photometric excess of ∼30 % during its active period, implying an approximate total coma dust mass of Md ∼ (7.2 ± 3.6) × 104 kg. From inactive data obtained in early 200...