J/A+A/705/A89ivo://CDS.VizieR/J/A+A/705/A89CDSVander Donckt M.Jehin E.Aravind K.Adami C.Hmiddouch S.Manfroid J.,Ganesh S.Benkhaldoun Z.Delsanti A.2026-01-09T09:22:32Z2026-01-09T10:20:47ZCDS support team

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

cds-question@unistra.frsolar-systemcometschemical-abundancesvisible-astronomyComet 12P/Pons-Brooks is a Halley-type comet known for its outbursting activity during its previous perihelia in 1883 and 1953. Its strong activity and favourable observing geometry gave a great opportunity to study this outburst-prone comet during its 2024 return with modern instruments. We aim to study the activity and composition of 12P/Pons-Brooks during its 2024 passage through long-slit spectroscopy and narrow- and broad-band photometry and imaging. The photometric survey contains over 130 nights of observation with TRAPPIST-North and -South from May 6, 2023 (rh=4.62au, inbound), to September 7, 2024 (rh=2.06au, outbound). We collected images with broad- band Johnson-Cousins filters (BVRcIc) and narrow-band HB filters (OH, CN, C2, C3, NH, and dust continuum). We obtained long-slit low-resolution spectra at the Observatoire de Haute Provence with the MISTRAL instrument on the night of March 23, 2024, at a heliocentric distance of 0.94au. The spectra were used to analyse the emissions from the different molecular bands. We detect nine strong outbursts, with an approximate two-week periodicity; OH production rate reaching values above 10^29^ molecules/s and A(0)f{rho} dust activity proxy above 10^5^cm. Dust images show the formation of a double-horned-shaped coma and the expansion of a dust shell in the days following the strongest outbursts. The gas-to-dust ratio behaviour during these events differs from other observations of outbursting comets closer to the Sun, while outbursts rather share similarities with the centaur comet 29P/Schwassmann-Wachmann's. The analysis of CN jets between 1.02 and 2.13au suggests a nucleus rotation period of either 29.45h or 58.90h and a gas ejection velocity of 1.03+/-0.09km/s. From the MISTRAL spectra, emission bands from C_2_, NH_2_, and CN were observed, as well as H_2_ O+ in the anti-sunward direction.2026A&A...705A..89Vhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/705/A89CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/705/A89https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/705/A89http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/705/A89https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/705/A89https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/705/A89http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/705/A89GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap2.762881831355591e-19 3.3785437584409506e-19OpticaldefaultJ/A+A/705/A89/tablea1Magnitude and colour indicesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUTdateUT date'Y:M:D'time.epochnullabledeltaTTime to reach periheliondtime.intervalfloatrhHeliocentric distanceaupos.distance;pos.heliocentricfloatdeltaGeocentric distanceaupos.distance;pos.geocentricfloatObsObservatory, TS: TRAPPIST-South; TN: TRAPPIST-Northmeta.id;instr.obstycharl_RcmagLimit flag on Rcmeta.code.errorcharRcmagRc magnitudemagphot.mag;em.opt.Rfloate_Rcmag? Rc magnitude errormagstat.error;phot.magfloatnullablel_FRcLimit flag on Rcmeta.code.errorcharFRcRc flux (10^-16^erg/cm^2^/s/{AA})1e-18W.m**-2.nm**-1phot.flux.density;em.opt.Rfloate_FRc? Rc flux error (10^-16^erg/cm^2^/s/{AA})1e-18W.m**-2.nm**-1stat.errorfloatnullableB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullablee_B-V? B-V colour index errormagstat.error;phot.color;em.opt.BfloatnullableV-Rc? V-Rc colour indexmagphot.color;em.opt.V;em.opt.Rfloatnullablee_V-Rc? V-Rc colour index errormagstat.error;phot.color;em.opt.VfloatnullableRc-Ic? Rc-Ic colour indexmagphot.color;em.opt.R;em.opt.Ifloatnullablee_Rc-Ic? Rc-Ic colour index errormagstat.error;phot.color;em.opt.RfloatnullableJ/A+A/705/A89/tablea2Production rates and A(0)f{rho} dust activity proxye_V? V-band A(0)f{rho} dust activity proxy errorcmstat.error;pos.cartesian.yintnullablel_RcLimit flag on Rcmeta.code.errorcharFC3? Measured C3 flux used to calculate production rate (10^26^molecules/s) (1)1e-17W.m**-2phot.fluxdoublenullablee_FC3? Measured C3 flux used to calculate production rate error (1)1e-17W.m**-2stat.errorfloatnullablel_FBLimit flag on FBmeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUTdateUT date'Y:M:D'time.epochnullabledeltaTtime to reach periheliondtime.intervalfloatrhheliocentric distanceaupos.distance;pos.heliocentricfloatdeltageocentric distanceaupos.distance;pos.geocentricfloatObsObservatory, TS: TRAPPIST-South; TN: TRAPPIST-Northmeta.id;instr.obstycharl_OHLimit flag on OHmeta.code.errorcharOH? OH production rate (10^26^molecules/s)1e+26s**-1phys.atmolintnullablee_OH? OH production rate error (10^26^molecules/s)1e+26s**-1stat.errorintnullableNH? NH production rate (10^26^molecules/s)1e+26s**-1phys.atmolfloatnullablee_NH? NH production rate error (10^26^molecules/s)1e+26s**-1stat.errorfloatnullableCN? CN production rate (10^26^molecules/s)1e+26s**-1phys.atmolfloatnullablee_CN? CN production rate error (10^26^molecules/s)1e+26s**-1stat.errorfloatnullableC2? C2 production rate (10^26^molecules/s)1e+26s**-1phys.atmolfloatnullablee_C2? C2 production rate error (10^26^molecules/s)1e+26s**-1stat.errorfloatnullableC3? C3 production rate (10^26 molecules/s)1e+26s**-1phys.atmolfloatnullablee_C3? C3 production rate error (10^26^molecules/s)1e+26s**-1stat.errorfloatnullablel_BLimit flag on Bmeta.code.errorcharB? B-band A(0)f{rho} dust activity proxycmphys.atmolintnullablee_B? B-band A(0)f{rho} dust activity proxy errorcmstat.errorintnullablel_VLimit flag on Vmeta.code.error;pos.cartesian.ycharV? V-band A(0)f{rho} dust activity proxycmphys.atmolintnullableRc? Rc-band A(0)f{rho} dust activity proxycmphys.atmolintnullablee_Rc? Rc-band A(0)f{rho} dust activity proxy errorcmstat.errorintnullablel_IcLimit flag on Icmeta.code.errorcharIc? Ic-band A(0)f{rho} dust activity proxycmphys.atmolintnullablee_Ic? Ic-band A(0)f{rho} dust activity proxy errorcmstat.errorintnullablel_FOHLimit flag on FOH (1)meta.code.errorcharFOH? Measured OH flux used to calculate production rate (1)1e-17W.m**-2phot.fluxdoublenullablee_FOH? Measured OH flux used to calculate production rate error (1)1e-17W.m**-2stat.errorfloatnullableFNH? Measured NH flux used to calculate production rate (1)1e-17W.m**-2phot.fluxfloatnullablee_FNH? Measured NH flux used to calculate production rate error (1)1e-17W.m**-2stat.errorfloatnullableFCN? Measured CN flux used to calculate production rate (1)1e-17W.m**-2phot.fluxdoublenullablee_FCN? Measured CN flux used to calculate production rate error (1)1e-17W.m**-2stat.errorfloatnullableFC2? Measured C2 flux used to calculate production rate (1)1e-17W.m**-2phot.fluxdoublenullablee_FC2? Measured C2 flux used to calculate production rate error (1)1e-17W.m**-2stat.errorfloatnullableFB? Measured B-band flux used to calculate A(0)f{rho} dust activity proxy (1)1e-18W.m**-2.nm**-1phot.fluxdoublenullablee_FB? Measured B-band flux used to calculate A(0)f{rho} dust activity proxy error (1)1e-18W.m**-2.nm**-1stat.errorfloatnullablel_FVLimit flag on FVmeta.code.errorcharFV? Measured V-band flux used to calculate A(0)f{rho} dust activity proxy (1)1e-18W.m**-2.nm**-1phot.fluxdoublenullablee_FV? Measured V-band flux used to calculate A(0)f{rho} dust activity proxy error (1)1e-18W.m**-2.nm**-1stat.errorfloatnullablel_FRcLimit flag on FRcmeta.code.errorcharFRc? Measured Rc-band flux used to calculate A(0)f{rho} dust activity proxy (1)1e-18W.m**-2.nm**-1phot.fluxfloatnullablee_FRc? Measured Rc-band flux used to calculate A(0)f{rho} dust activity proxy error (1)1e-18W.m**-2.nm**-1stat.errorfloatnullablel_FIcLimit flag on FIcmeta.code.errorcharFIc? Measured Ic-band flux used to calculate A(0)f{rho} dust activity proxy (1)1e-18W.m**-2.nm**-1phot.fluxfloatnullablee_FIc? Measured Ic-band flux used to calculate A(0)f{rho} dust activity proxy error (1)1e-18W.m**-2.nm**-1stat.errorfloatnullable