J/AJ/156/223ivo://CDS.VizieR/J/AJ/156/223doi:10.26093/cds/vizier.51560223CDSHsieh H.H.Ishiguro M.Kim Y.Knight M.M.Lin Z.-Y.Micheli M.,Moskovitz N.A.Sheppard S.S.Thirouin A.Trujillo C.A.2019-05-07T07:19:26Z2019-04-25T13:29:06ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsolar-systemcometsphotometryvisible-astronomyWe report observations of the reactivations of the main-belt comets (MBCs) 238P/Read and 288P/(300163) 2006 VW_139_ 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 M_d_=0.7+/-0.3 kg/s and a best-fit start date of 2016 March 11 (when the object was at a true anomaly of {nu}=-63{deg}) for 238P, and an initial average net dust production rate of M_d_=5.6+/-0.7 kg/s and a best-fit start date of 2016 August 5 (when the object was at {nu}=-27{deg}) 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.2018AJ....156..223Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/156/223CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/505/1297 : Hawaii Trails Project (Hsieh, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/156/223https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/156/223http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/156/223https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/156/223https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/156/223http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/156/223GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/156/223/obslogObservation log of 238P (active) (table 1) , 288P (active) (table 3) , and 288P (inactive) (table 4)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCometCometmeta.id;meta.maincharDateUT date of observationtime.epoch;obsnullableTelTelescope used (1)instr.setupcharNexp[1/35]? Number of exposures (not in Tables 2,5)meta.numberintnullableTint[54/7200]? Total integration time (not in Tables 2,5)stime.epochintnullableFilt[R r'] Filter (not in Tables 2,5)meta.id;instr.filtercharv[-125/140.2] True anomaly {nu}degsrc.orbital.meanAnomalyfloatHDist[2.361/3.458] Heliocentric distanceAUpos.distance;pos.heliocentricfloatGDist[1.368/3.566] Geocentric distanceAUpos.distance;pos.geocentricfloatalpha[0.5/25.2] Solar phase angle (Sun-object-Earth) {alpha}degpos.angDistancefloatRmag[18.6/23.2]? Equivalent mean apparent R-band nucleus magnitude, measured within photometry apertures with radii of 4.0"magphot.mag;em.opt.Rfloatnullablee_Rmag[0.02/0.14]? Uncertainty in Rmagmagstat.error;phot.mag;em.opt.Rfloatnullablel_RmagT[<] Limit flag on RmagTmeta.code.errorcharRmagT[18.6/22.3]? Equivalent total mean apparent R-band magnitude, including the entire coma and tail, if presentmagphot.mag;em.opt.Rfloatnullablee_RmagT[0.1]? Uncertainty in RmagT (not in Tables 2,5)magstat.error;phot.mag;em.opt.Rfloatnullablel_RMag[<] Limit flag on RMag (not in Table 4)meta.code.errorcharRMag[14.6/18.3]? Total absolute R-band magnitude, using the H, G phase function (not in Table 4) (2)magphot.mag;em.opt.Rfloatnullablee_RMag[0.1/0.2]? Uncertainty in RMag (not in Tables 2,4,5)magstat.error;phot.mag;em.opt.Rfloatnullablel_Mdust[>] Limit flag on Mdust (not in Table 4)meta.code.errorcharMdust[2e+06/8.7e+07]? Estimated total dust mass, assuming {rho}_d_~2500 kg/m^3^ (not in Table 4)kgphys.massdoublenullablee_Mdust[1e+06/2e+07]? Uncertainty in Mdust (not in Table 4)kgstat.errordoublenullableAfrho[1/14.7]? Af{rho} value computed using photometry apertures with radii of 4.0" where uncertainties are estimated to be ~10% (not in Tables 2,4,5)cmstat.fit.paramfloatnullablee_Afrho[0.1/2.9]? Uncertainty in Afrho (not in Tables 2,4,5)cmstat.errorfloatnullableRmagR[16.84/18.09]? Estimated reduced R-band magnitude at the midpoint of the full photometric range (assumed to be 0.80 mag) of the rotational light curve (only in Table 4)magphot.mag;em.opt.Rfloatnullablee_RmagR[0.05/0.4]? Uncertainty in RmagR (only in Table 4)magstat.error;phot.mag;em.opt.RfloatnullableJ/AJ/156/223/previousobsPreviously reported observations of 238P (table 2) and 288P (table 5) when activesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCometCometmeta.id;meta.maincharDateUT date of observationtime.epoch;obsnullableTelTelescope used (1)instr.setupcharv[-125/140.2] True anomaly {nu}degsrc.orbital.meanAnomalyfloatHDist[2.361/3.458] Heliocentric distanceAUpos.distance;pos.heliocentricfloatGDist[1.368/3.566] Geocentric distanceAUpos.distance;pos.geocentricfloatalpha[0.5/25.2] Solar phase angle (Sun-object-Earth) {alpha}degpos.angDistancefloatRmag[18.6/23.2]? Equivalent mean apparent R-band nucleus magnitude, measured within photometry apertures with radii of 4.0"magphot.mag;em.opt.Rfloatnullablee_Rmag[0.02/0.14]? Uncertainty in Rmagmagstat.error;phot.mag;em.opt.Rfloatnullablel_RmagT[<] Limit flag on RmagTmeta.code.errorcharRmagT[18.6/22.3]? Equivalent total mean apparent R-band magnitude, including the entire coma and tail, if presentmagphot.mag;em.opt.Rfloatnullablel_RMag[<] Limit flag on RMag (not in Table 4)meta.code.errorcharRMag[14.6/18.3]? Total absolute R-band magnitude, using the H, G phase function (not in Table 4) (2)magphot.mag;em.opt.Rfloatnullablel_Mdust[>] Limit flag on Mdust (not in Table 4)meta.code.errorcharMdust[2e+06/8.7e+07]? Estimated total dust mass, assuming {rho}_d_~2500 kg/m^3^ (not in Table 4)kgphys.massdoublenullablee_Mdust[1e+06/2e+07]? Uncertainty in Mdust (not in Table 4)kgstat.errordoublenullable