Oleksandra V. Ivanova

Monitoring of the cometary activity of distant comet C/2006 S3 (LONEOS)

Context. The study of small bodies that have a cometary activity at a large heliocentric distance (larger than 5 au) is important for a better understanding of the physical properties of comets and their origin. Such studies require long-term monitoring and a significant observational effort. Aims. Our goal is to monitor the cometary activity and search for possible emission lines of C/2006 S3 (LONEOS), which is a distant comet that was discovered in 2006 and passed perihelion at 5.13 au in April 2012. Methods. We performed different observing runs with telescopes, ranging from 2 m to 6 m both in imaging and spectroscopic modes in the optical range, between 2006 and 2014. Results. The comet C/2006 S3 (LONEOS) was a very active object with Afρ ∼ 4000 cm at its maximum of activity, corresponding to a dust production rate of 82 kg s −1 , considering a mean geometric albedo of 0.1 and grain outflow velocities in the range 2−22 m s −1 . It appeared to be more active after its perihelion than before and we did not manage to detect any emission lines. Upper limits for the main cometary species that have emission bands in the optical range are provided. Our dust environment modeling is in agreement with a collimated source of dust that appeared in 2013.

Colour variations of Comet C/2013 UQ4 (Catalina)

We report observations of color in the inner coma of Comet C/2013 UQ4 (Catalina) with the broadband B and R filters. We find significant temporal variations of the color slope, ranging from -12.67

Comet C/2011 J2 (LINEAR): Photometry and stellar transit

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Optical spectrophotometric monitoring of comet C/2006 W3 (Christensen) before perihelion

8.16 \% per 0.1~

Polarimetric and spectroscopic observations of a dynamically new comet C/2012 J1 (Catalina)

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Dust tail of the active distant Comet C/2003 WT42 (LINEAR) studied with photometric and spectroscopic observations

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C/2002 VQ94 (LINEAR) and 29P/Schwassmann–Wachmann 1 — CO+ and N+2 rich comets

35.09 \pm 11.7

Observations of the long-lasting activity of the distant Comets 29P Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR) and C/2002 VQ94 (LINEAR)

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Distant activity of Comet C/2002 VQ94 (LINEAR): Optical spectrophotometric monitoring between 8.4 and 16.8 au from the Sun

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Cometary activity of distant object C/2002 VQ94 (LINEAR)

m.It is significant that the comet changes color from red to blue over only a two-day period. Such dispersion cannot be characterized with an average color slope. We also observe Comet C/2013 UQ4 (Catalina) in infrared using Spitzer and find no significant CO/CO