Properties of the nuclei and comae of 10 ecliptic comets from Hubble Space Telescope multi-orbit observations star - Archive ouverte HAL
Article Dans Une Revue Monthly Notices of the Royal Astronomical Society Année : 2011

Properties of the nuclei and comae of 10 ecliptic comets from Hubble Space Telescope multi-orbit observations star

P. L. Lamy
  • Fonction : Auteur
I. Toth
  • Fonction : Auteur
H. A. Weaver
  • Fonction : Auteur
Michael F. A'Hearn
  • Fonction : Auteur
L. Jorda

Résumé

We report on our on-going effort to detect and characterize cometary nuclei with the Hubble Space Telescope (HST). During cycle 9 (2000 July to 2001 June), we performed multi-orbit observations of 10 ecliptic comets with the Wide Field Planetary Camera 2. Nominally, eight contiguous orbits covering a time interval of similar to 11 h were devoted to each comet but a few orbits were occasionally lost. In addition to the standard R band, we could additionally observe four of them in the V band and the two brightest ones in the B band. Time series photometry was used to constrain the size, shape and rotational period of the 10 nuclei. Assuming a geometric albedo of 0.04 for the R band, a linear phase law with a coefficient of 0.04 mag deg-1 and an opposition effect similar to that of comet 19P/Borrelly, we determined the following mean values of the effective radii 47P/Ashbrook-Jackson: 2.86 +/- 0.08 km, 61P/Shajn-Schaldach: 0.62 +/- 0.02 km, 70P/Kojima: 1.83 +/- 0.05 km, 74P/Smirnova-Chernykh: 2.23 +/- 0.04 km, 76P/West-Kohoutek-Ikemura: 0.30 +/- 0.02 km, 82P/Gehrels 3: 0.69 +/- 0.02 km, 86P/Wild 3: 0.41 +/- 0.03 km, 87P/Bus: 0.270.01 km, 110P/Hartley 3: 2.15 +/- 0.04 km and 147P/Kushida-Muramatsu: 0.21 +/- 0.01 km. Because of the limited time coverage (similar to 11 h), the rotational periods could not be accurately determined, multiple solutions were sometime found and three periods were not constrained at all. Our estimates range from similar to 5 to similar to 32 h. The lower limits for the ratio a/b of the semi-axis of the equivalent spheroids range from 1.10 (70P) to 2.20 (87P). The four nuclei for which we could measure (V - R) are all significantly redder than the Sun, with 86P/Wild 3 (V - R) = 0.86 +/- 0.10 appearing as an ultrared object. We finally determined the dust activity parameter Af of their coma in the R band, the colour indices and the reflectivity spectra of four of them.

Dates et versions

hal-01438046 , version 1 (17-01-2017)

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P. L. Lamy, I. Toth, H. A. Weaver, Michael F. A'Hearn, L. Jorda. Properties of the nuclei and comae of 10 ecliptic comets from Hubble Space Telescope multi-orbit observations star. Monthly Notices of the Royal Astronomical Society, 2011, 412 (3), pp.1573--1590. ⟨10.1111/j.1365-2966.2010.17934.x⟩. ⟨hal-01438046⟩
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