The Perihelion Emission of Comet C/2010 L5 (WISE)

Abstract

The only Halley-type comet discovered by the Wide-Field Infrared Survey Explorer (WISE), C/2010 L5 (WISE), was imaged three times by WISE, and it showed a significant dust tail during the second and third visits (2010 June and July, respectively). We present here an analysis of the data collected by WISE, putting estimates on the comet's size, dust production rate, gas production (CO+CO 2 ) rate, and active fraction. We also present a detailed description of a novel tail-fitting technique that allows the commonly used syndyne-synchrone models to be used analytically, thereby giving more robust results. We find that C/2010 L5ʼs dust tail was likely formed by strong emission, likely in the form of an outburst, occurring when the comet was within a few days of perihelion. Analyses of the June and July data independently agree on this result. The two separate epochs of dust tail analysis independently suggest a strong emission event close to perihelion. The average size of the dust particles in the dust tail increased between the epochs, suggesting that the dust was primarily released in a short period of time, and the smaller dust particles were quickly swept away by solar radiation pressure, leaving the larger particles behind. The difference in CO 2 and dust production rates measured in 2010 June and July is not consistent with "normal" steady-state gas production from a comet at these heliocentric distances, suggesting that much of the detected CO 2 and dust was produced in an episodic event. Together, these conclusions suggest that C/2010 L5 experienced a significant outburst event when the comet was close to perihelion.

Debiasing the NEOWISE Cryogenic Mission Comet Populations

“…Size and εfρ.-Large-grained dust particles from cometary comae can remain in the vicinity of the nucleus for years (Stevenson et al 2014), and observations at infrared wavelengths tend to be more sensitive to the presence of larger grains (Bauer et al 2008;Kramer et al 2017). We thus expect the observed weaker correlation with distance as compared to the production of gas species such as CO or CO 2 (Bauer et al 2015).…”

THENEOWISE-DISCOVERED COMET POPULATION AND THE CO + CO2PRODUCTION RATES

“…It is unlikely, then, that outgassing had completely ceased very soon after perihelion. This particular case is discussed in detail in Kramer et al 2015. 9/28/15 12:07 PM P/2010 N1 (WISE): This inbound JFC was discovered at a heliocentric distance of 1.55 AU, 41 days prior to its perihelion.…”

“…We also note below that WISE imaged the predicted position of C/2010 L5 in January, before its discovery and did not detect the comet. The detection threshold is less than, but on the order of, the listed nucleus size in Table 3 (Kramer et al 2015).…”

Maximizing LSST Solar System Science: Approaches, Software Tools, and Infrastructure Needs

“…For sufficiently bright comets, more advanced morphology characterization could include automated basic Finson-Probstein dust modeling (Finson & Probstein, 1968;Kramer et al, 2017), which is commonly used to infer ejection times, ejection velocities, and grain size distributions for cometary dust emission from observed morphology. Simple automated fitting of cometary surface brightness profiles to a syndyne-synchrone network characteristic of this type of dust modeling could produce approximate estimates of parameters such as grain sizes or ejection start times for a large number of comets observed by LSST, allowing for searches for trends with such parameters as comet brightness, nucleus size, dynamical characteristics, and heliocentric distance.…”