The 2016 Reactivations of the Main-belt Comets 238P/Read and 288P/(300163) 2006 VW₁₃₉*

Abstract

We report observations of the reactivations of the main-belt comets (MBCs) 238P/Read and 288P/(300163) 2006 VW139 that also track the evolution of each object’s activity over several months in 2016 and 2017. We additionally identify and analyze archival SDSS data showing 288P to have been active in 2000, meaning that both 238P and 288P have now each been confirmed to be active near perihelion on three separate occasions. From data obtained of 288P from 2012–2015 when it appeared inactive, we find best-fit R-band H, G phase function parameters of H R = 16.80 ± 0.12 mag and G R = 0.18 ± 0.11, corresponding to effective component radii of r c = 0.80 ± 0.04 km, assuming a binary system with equally sized components. Fitting linear functions to ejected dust masses inferred for 238P and 288P soon after their observed reactivations in 2016, we find an initial average net dust production rate of kg s−1 and a best-fit start date of 2016 March 11 (when the object was at a true anomaly of ν = −63°) for 238P, and an initial average net dust production rate of kg s−1 and a best-fit start date of 2016 August 5 (when the object was at ν = −27°) for 288P. Applying similar analyses to archival data, we find similar start points for previous active episodes for both objects, suggesting that minimal mantle growth or ice recession occurred between the active episodes in question. Some changes in dust production rates between active episodes are detected, however. More detailed dust modeling is suggested to further clarify the process of activity evolution in MBCs.

Research of activity of Main Belt Comets 176P/LINEAR, 238P/Read and 288P/(300163) 2006 VW139

“…Hsieh et al . 23 published a paper about the 2016 reactivations of 238P and 288P recently, they reported observations of 238P and 288P from 2016 July to 2017 January in this paper. Our observation dates are in this time frame, but are not included in their observation Logs.…”

“…As the determination of the dust production rate of a comet is highly model-dependent and parameter-dependent, we can’t compare the dust production rates obtained in this work to other works directly. To compare activitiy of 238P and 288P in this work to Hsieh et al .’s 23 work and other MBCs. We computed the total mass M dust of visible ejected dust by using of equation 23 …”

“…To compare activitiy of 238P and 288P in this work to Hsieh et al .’s 23 work and other MBCs. We computed the total mass M dust of visible ejected dust by using of equation 23 …”

“…When it was discovered, it showed cometary activity. 238P repeated activity during its 2011 and 2016 perihelion passage 21–23 . The last perihelion passage of 238P was on 2016 October 22.…”

“…288P/(300163) 2006 VW 139 (also known as asteroid 300163, formerly 2006 VW 139 , hereafter 288P) was discovered in 2006 and first observed to be active on UT 2011 August 30 24 . 288P was reported the reactivation during its 2016 perihelion passage 23,25 . The last perihelion passage of 288P was on 2016 November 08.…”