Rotation of the Nucleus, Gas Kinematics and Emission Pattern of Comet 8P/Tuttle: Preliminary Results from Optical Imaging of the CN Coma

• Published in: Earth, moon, and planets Vol. 105; no. 2-4; pp. 327 - 342
• Main Authors: Waniak, W., Borisov, G., Drahus, M., Bonev, T., Czart, K., Küppers, M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2009; Springer Nature B.V
• Subjects: Astronomy; Astrophysics; Astrophysics and Astroparticles; Comets; Emissions; Gases; Kinematics; Observations and Techniques; Physics; Physics and Astronomy; Planetology; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Wavelengths; Comets; CN coma; Gas emission; Comet 8P/Tuttle; Nucleus rotation
• ISSN: 0167-9295; 1573-0794
• DOI: 10.1007/s11038-009-9326-7

We present preliminary results of the narrow-band CN observations of comet 8P/Tuttle from early January 2008, realized as part of a project consisting of near-simultaneous spectroscopic monitoring of HCN at millimeter-wavelengths and optical imaging of the coma. The mean-image subtraction method revealed low-contrast CN envelopes. Using the image cross-correlation technique we measured the projected velocity of these shells. For the sunward part we found it to be equal to 0.96 ± 0.03 km s −1 on January 4 and 1.10 ± 0.01 km s −1 on January 9, whereas the anti-sunward part reached 0.73 ± 0.05 and 0.80 ± 0.02 km s −1 , respectively. The periodicity of gas emission was investigated using a repeatability of the shells, their kinematics, and an aperture photometry of the near nucleus region. We found a period of 5.70 ± 0.07 h (along with multiples), consistent with previous findings by other authors. A toy Monte Carlo model was implemented to reproduce the time-series of the CN images. We show that emission of HCN into a relatively wide cone by a single active region on a rotating nucleus is the most probable scenario.