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Radio meteors above the Arctic Circle: radiants, orbits and estimated magnitudes Csilla Szasz IRF Scientific Report 294, 2008 (cid:42)(cid:47)(cid:52)(cid:53)(cid:42)(cid:53)(cid:54)(cid:53)(cid:38)(cid:53)(cid:1)(cid:39)(cid:189)(cid:51)(cid:1)(cid:51)(cid:58)(cid:46)(cid:37)(cid:39)(cid:58)(cid:52)(cid:42)(cid:44) (cid:52)(cid:88)(cid:70)(cid:69)(cid:74)(cid:84)(cid:73)(cid:1)(cid:42)(cid:79)(cid:84)(cid:85)(cid:74)(cid:85)(cid:86)(cid:85)(cid:70)(cid:1)(cid:80)(cid:71)(cid:1)(cid:52)(cid:81)(cid:66)(cid:68)(cid:70)(cid:1)(cid:49)(cid:73)(cid:90)(cid:84)(cid:74)(cid:68)(cid:84) (cid:44)(cid:74)(cid:83)(cid:86)(cid:79)(cid:66)(cid:13)(cid:1)(cid:52)(cid:88)(cid:70)(cid:69)(cid:70)(cid:79) !!! """ RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES Akademiskavhandling sommedvederbo¨rligttillsta˚ndavrektorsa¨mbetetvidUmea˚ universitet fo¨ravla¨ggandeavteknologiedoktorsexamenirymdteknikframla¨gges tilloffentliggranskningiIRF:saula,tisdagenden6maj2008,kl. 9:00 av CsillaSzasz FAKULTETSOPPONENT Dr. NoahBrosch,TelAvivUniversity,TelAviv,Israel RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES Csilla Szasz IRFScientificReport294 RADIOMETEORER OVAN POLCIRKELN: RADIANTER, BANOR OCH UPPSKATTADE MAGNITUDER SwedishInstituteofSpacePhysics Kiruna2008 Coverillustration: Thesun,theEarthand39meteoroidorbits BLUECURVES: OrbitsofEarth( ),Mars( ),Jupiter( )andSaturn( )aroundthesun( ) ⊕ " GREENCURVES: progrademeteoroidorbi♂ts " # REDCURVES: retrogrademeteoroidorbits CSILLASZASZandJOHANKERO c CsillaSzasz # DOCTORALTHESISATTHESWEDISHINSTITUTEOFSPACEPHYSICS RadiometeorsabovetheArcticCircle:radiants,orbitsandestimatedmagnitudes DOKTORSAVHANDLINGVIDINSTITUTETFO¨RRYMDFYSIK Radiometeorerovanpolcirkeln:radianter,banorochuppskattademagnituder TypesetbytheauthorinLATEX. Kiruna,March2008 IRFScientificReport294 ISSN0284-1703 ISBN978-91-977255-2-1 PrintedattheSwedishInstituteofSpacePhysics Box812 SE-98128,Kiruna,Sweden March2008 v RADIOMETEORER OVAN POLCIRKELN: RADIANTER, BANOR OCH UPPSKATTADE MAGNITUDER SAMMANFATTNING Avhandlingens resultat a¨r baserade pa˚ ma¨tningar med den trestatiska EISCAT UHF- radarn och tre SKiYMet meteorradarsystem. En metod fo¨r meteoroidbanbera¨kning presenterasidetalj. EISCATUHF-systemetbesta˚ravtreidentiska,32mstoraparabolantenner: enho¨g- effektssa¨ndare/mottagare och tva˚ fja¨rrstyrda mottagare. Under fyra 24-timmarsma¨t- ningar vid va˚r-/ho¨stdagja¨mning och sommar-/vintersolsta˚nd mellan 2002 och 2005 detekterades 410 meteoriska huvudekon simultant med alla tre mottagare. Dessa tre- statiskameteorersatmosfa¨rsinbromsningochradartva¨rsnittharfaststa¨lltsmycketnog- grant och anva¨nts till att bera¨kna meteoroidernas banor samt uppskatta meteorernas luminositeter. Ingenavdeobserverademeteoroidernaverkarvaraavinterstella¨rteller asteroidursprung. Derastroligasteursprunga¨rkometer,framfo¨ralltkortperiodskome- ter (< 200 a˚r). Ungefa¨r 40% av meteorradianterna kan associeras till norra apex, ett ka¨llomra˚defo¨rsporadiskameteorer,ochtotalta¨r58%avpartiklarnasbanorretrograda. Meteoroidernas geocentriska hastighetsfo¨rdelning har tva˚ lokala maxima: ett fo¨r den prograda populationen vid 38km/s och ett fo¨r den retrograda vid 59km/s. Genom att anpassa datat till en numerisk ablationsmodell som simulerar meteoroidernas fa¨rd genomatmosfa¨renhardedetekterademeteorernasabsolutavisuellamagnituderupp- skattatstillmellan+9och+5. Dettainneba¨rattdea¨robserverbaramedbildfo¨rsta¨rkta, teleskopiskaCCD-kameror. Avhandlingendiskuterara¨venhursporadiskameteorersdygns-ochsa¨songsinflo¨de berorpa˚geografisklatitudochmeteorradianternasdistributionpa˚himmelssfa¨ren.Detta utreds med hja¨lp av spa˚rekon detekterade under perioden 1999-2004 med tre meteor- radarsystem pa˚ latituderna 68 N, 55 N och 8 S. Dygnsinflo¨det varierar mest pa˚ la˚ga ◦ ◦ ◦ latituder och minst pa˚ ho¨ga. Ju ho¨gre latitud, desto mer fo¨ra¨ndras da¨remot dygns- inflo¨deto¨vera˚ret. Avhandlingenvisarattdedominerandeka¨llomra˚denavarierarmed sa¨song,o¨verdygnetochmedlatitud. Ba˚deEISCATUHF-systemetochmeteorradarnpa˚ 68 Na¨rbela¨gnana¨rapolcirkeln. ◦ Detta inneba¨r att norra ekliptiska polen (NEP) a¨r i zenit en ga˚ng per dygn, a˚ret om. Vid just denna tidpunkt sammanfaller ekliptikan med den lokala horisonten, vilket mo¨jliggo¨rattdetobserverademeteorinflo¨detfra˚nnorraekliptiskahemisfa¨renkanja¨m- fo¨ras o¨ver a˚ret. Under timmen da˚ NEP a¨r na¨rmast zenit har EISCAT UHF uppma¨tt ett ungefa¨r tre ga˚nger ho¨gre meteorinflo¨de vid sommarsolsta˚ndet a¨n under de andra sa¨songerna,vilketo¨verenssta¨mmermedresultatenfra˚nmeteorradarnpa˚ 68 N. ◦ NYCKELORD: meteorer, meteoroider, interplaneta¨rt stoft, meteorradianter, meteoroid- banor,sporadiskaka¨llomra˚den,radar vii RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES ABSTRACT This thesis presents results based on data collected with the 930MHz EISCAT UHF radarsystemandthreeSKiYMetspecularmeteorradars. Itdescribesindetailamethod formeteoroidorbitcalculation. The EISCAT UHF system comprises three identical 32m parabolic antennae: one high-powertransmitter/receiverandtworemotereceivers. Precisemeteoroiddeceler- ation and radar cross section are determined from 410 meteor head echoes simultane- ously observed with all three receivers between 2002 and 2005, during four 24h runs atthesummer/wintersolsticeandthevernal/autumnalequinox. Theobservationsare usedtocalculatemeteoroidorbitsandestimatemeteorvisualmagnitudes. Noneofthe observed meteors appear to be of extrasolar or asteroidal origin; comets, particularly shortperiod(<200years)ones,maybethedominantsourcefortheparticlesobserved. About 40% of the radiants are associated with the north apex sporadic meteor source and 58% of the orbits are retrograde. The geocentric velocity distribution is bimodal withaprogradepopulationcentredaround38km/sandaretrogradepopulationpeak- ing at 59km/s. The absolute visual magnitudes of meteors are estimated to be in the rangeof+9to+5usingasingle-objectnumericalablationmodel. Theyarethusobserv- ableusingintensifiedCCDcameraswithtelephotolenses. Thethesisalsoinvestigatesdiurnalmeteorratedifferencesandsporadicmeteorra- diantdistributionsatdifferentlatitudesusingspecularmeteortrailradarmeasurements from68 N,from55 Nandfrom8 S.Thelargestdifferenceinamplitudeofthediurnal ◦ ◦ ◦ flux variation is at equatorial latitudes, the lowest variation is found at high latitudes. Thelargestseasonalvariationofthediurnalfluxisobservedwiththehigh-latitudeme- teor radar. The investigations show a variation in the sources with both latitude and timeofday. TheEISCATUHFsystemandthehigh-latitudemeteorradararelocatedclosetothe ArcticCircle. SuchageographicalpositionmeansthatzenithpointstowardstheNorth EclipticPole(NEP)onceeverydayallyearround. Thisparticulargeometryallowsthe meteoroid influx from the north ecliptic hemisphere to be compared throughout the year as the ecliptic plane coincides with the local horizon. Considering only the hour whenNEPisclosesttozenith,theEISCATUHFheadechorateisaboutafactorofthree higheratsummersolsticethanduringtheotherseasons, afindingwhichisconsistent withthehigh-latitudemeteorradarmeasurements. KEYWORDS: meteors, meteoroids, dust, meteor radiants, meteoroid orbits, sporadic sources,radar

Description:
high-power transmitter/receiver and two remote receivers. when NEP is closest to zenith, the EISCAT UHF head echo rate is about a factor of three . 7.5 Paper V: Quantitative Comparison of a New Ab Initio Micrometeor .. Table 1: Dates and times for meteor campaigns with the EISCAT UHF system.
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Radio meteors above the Arctic Circle: radiants, orbits and estimated magnitudes Csilla Szasz IRF Scientific Report 294, 2008 (cid:42)(cid:47)(cid:52)(cid:53)(cid:42)(cid:53)(cid:54)(cid:53)(cid:38)(cid:53)(cid:1)(cid:39)(cid:189)(cid:51)(cid:1)(cid:51)(cid:58)(cid:46)(cid:37)(cid:39)(cid:58)(cid:52)(cid:42)(cid:44) (cid:52)(cid:88)(cid:70)(cid:69)(cid:74)(cid:84)(cid:73)(cid:1)(cid:42)(cid:79)(cid:84)(cid:85)(cid:74)(cid:85)(cid:86)(cid:85)(cid:70)(cid:1)(cid:80)(cid:71)(cid:1)(cid:52)(cid:81)(cid:66)(cid:68)(cid:70)(cid:1)(cid:49)(cid:73)(cid:90)(cid:84)(cid:74)(cid:68)(cid:84) (cid:44)(cid:74)(cid:83)(cid:86)(cid:79)(cid:66)(cid:13)(cid:1)(cid:52)(cid:88)(cid:70)(cid:69)(cid:70)(cid:79) !!! """ RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES Akademiskavhandling sommedvederbo¨rligttillsta˚ndavrektorsa¨mbetetvidUmea˚ universitet fo¨ravla¨ggandeavteknologiedoktorsexamenirymdteknikframla¨gges tilloffentliggranskningiIRF:saula,tisdagenden6maj2008,kl. 9:00 av CsillaSzasz FAKULTETSOPPONENT Dr. NoahBrosch,TelAvivUniversity,TelAviv,Israel RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES Csilla Szasz IRFScientificReport294 RADIOMETEORER OVAN POLCIRKELN: RADIANTER, BANOR OCH UPPSKATTADE MAGNITUDER SwedishInstituteofSpacePhysics Kiruna2008 Coverillustration: Thesun,theEarthand39meteoroidorbits BLUECURVES: OrbitsofEarth( ),Mars( ),Jupiter( )andSaturn( )aroundthesun( ) ⊕ " GREENCURVES: progrademeteoroidorbi♂ts " # REDCURVES: retrogrademeteoroidorbits CSILLASZASZandJOHANKERO c CsillaSzasz # DOCTORALTHESISATTHESWEDISHINSTITUTEOFSPACEPHYSICS RadiometeorsabovetheArcticCircle:radiants,orbitsandestimatedmagnitudes DOKTORSAVHANDLINGVIDINSTITUTETFO¨RRYMDFYSIK Radiometeorerovanpolcirkeln:radianter,banorochuppskattademagnituder TypesetbytheauthorinLATEX. Kiruna,March2008 IRFScientificReport294 ISSN0284-1703 ISBN978-91-977255-2-1 PrintedattheSwedishInstituteofSpacePhysics Box812 SE-98128,Kiruna,Sweden March2008 v RADIOMETEORER OVAN POLCIRKELN: RADIANTER, BANOR OCH UPPSKATTADE MAGNITUDER SAMMANFATTNING Avhandlingens resultat a¨r baserade pa˚ ma¨tningar med den trestatiska EISCAT UHF- radarn och tre SKiYMet meteorradarsystem. En metod fo¨r meteoroidbanbera¨kning presenterasidetalj. EISCATUHF-systemetbesta˚ravtreidentiska,32mstoraparabolantenner: enho¨g- effektssa¨ndare/mottagare och tva˚ fja¨rrstyrda mottagare. Under fyra 24-timmarsma¨t- ningar vid va˚r-/ho¨stdagja¨mning och sommar-/vintersolsta˚nd mellan 2002 och 2005 detekterades 410 meteoriska huvudekon simultant med alla tre mottagare. Dessa tre- statiskameteorersatmosfa¨rsinbromsningochradartva¨rsnittharfaststa¨lltsmycketnog- grant och anva¨nts till att bera¨kna meteoroidernas banor samt uppskatta meteorernas luminositeter. Ingenavdeobserverademeteoroidernaverkarvaraavinterstella¨rteller asteroidursprung. Derastroligasteursprunga¨rkometer,framfo¨ralltkortperiodskome- ter (< 200 a˚r). Ungefa¨r 40% av meteorradianterna kan associeras till norra apex, ett ka¨llomra˚defo¨rsporadiskameteorer,ochtotalta¨r58%avpartiklarnasbanorretrograda. Meteoroidernas geocentriska hastighetsfo¨rdelning har tva˚ lokala maxima: ett fo¨r den prograda populationen vid 38km/s och ett fo¨r den retrograda vid 59km/s. Genom att anpassa datat till en numerisk ablationsmodell som simulerar meteoroidernas fa¨rd genomatmosfa¨renhardedetekterademeteorernasabsolutavisuellamagnituderupp- skattatstillmellan+9och+5. Dettainneba¨rattdea¨robserverbaramedbildfo¨rsta¨rkta, teleskopiskaCCD-kameror. Avhandlingendiskuterara¨venhursporadiskameteorersdygns-ochsa¨songsinflo¨de berorpa˚geografisklatitudochmeteorradianternasdistributionpa˚himmelssfa¨ren.Detta utreds med hja¨lp av spa˚rekon detekterade under perioden 1999-2004 med tre meteor- radarsystem pa˚ latituderna 68 N, 55 N och 8 S. Dygnsinflo¨det varierar mest pa˚ la˚ga ◦ ◦ ◦ latituder och minst pa˚ ho¨ga. Ju ho¨gre latitud, desto mer fo¨ra¨ndras da¨remot dygns- inflo¨deto¨vera˚ret. Avhandlingenvisarattdedominerandeka¨llomra˚denavarierarmed sa¨song,o¨verdygnetochmedlatitud. Ba˚deEISCATUHF-systemetochmeteorradarnpa˚ 68 Na¨rbela¨gnana¨rapolcirkeln. ◦ Detta inneba¨r att norra ekliptiska polen (NEP) a¨r i zenit en ga˚ng per dygn, a˚ret om. Vid just denna tidpunkt sammanfaller ekliptikan med den lokala horisonten, vilket mo¨jliggo¨rattdetobserverademeteorinflo¨detfra˚nnorraekliptiskahemisfa¨renkanja¨m- fo¨ras o¨ver a˚ret. Under timmen da˚ NEP a¨r na¨rmast zenit har EISCAT UHF uppma¨tt ett ungefa¨r tre ga˚nger ho¨gre meteorinflo¨de vid sommarsolsta˚ndet a¨n under de andra sa¨songerna,vilketo¨verenssta¨mmermedresultatenfra˚nmeteorradarnpa˚ 68 N. ◦ NYCKELORD: meteorer, meteoroider, interplaneta¨rt stoft, meteorradianter, meteoroid- banor,sporadiskaka¨llomra˚den,radar vii RADIO METEORS ABOVE THE ARCTIC CIRCLE: RADIANTS, ORBITS AND ESTIMATED MAGNITUDES ABSTRACT This thesis presents results based on data collected with the 930MHz EISCAT UHF radarsystemandthreeSKiYMetspecularmeteorradars. Itdescribesindetailamethod formeteoroidorbitcalculation. The EISCAT UHF system comprises three identical 32m parabolic antennae: one high-powertransmitter/receiverandtworemotereceivers. Precisemeteoroiddeceler- ation and radar cross section are determined from 410 meteor head echoes simultane- ously observed with all three receivers between 2002 and 2005, during four 24h runs atthesummer/wintersolsticeandthevernal/autumnalequinox. Theobservationsare usedtocalculatemeteoroidorbitsandestimatemeteorvisualmagnitudes. Noneofthe observed meteors appear to be of extrasolar or asteroidal origin; comets, particularly shortperiod(<200years)ones,maybethedominantsourcefortheparticlesobserved. About 40% of the radiants are associated with the north apex sporadic meteor source and 58% of the orbits are retrograde. The geocentric velocity distribution is bimodal withaprogradepopulationcentredaround38km/sandaretrogradepopulationpeak- ing at 59km/s. The absolute visual magnitudes of meteors are estimated to be in the rangeof+9to+5usingasingle-objectnumericalablationmodel. Theyarethusobserv- ableusingintensifiedCCDcameraswithtelephotolenses. Thethesisalsoinvestigatesdiurnalmeteorratedifferencesandsporadicmeteorra- diantdistributionsatdifferentlatitudesusingspecularmeteortrailradarmeasurements from68 N,from55 Nandfrom8 S.Thelargestdifferenceinamplitudeofthediurnal ◦ ◦ ◦ flux variation is at equatorial latitudes, the lowest variation is found at high latitudes. Thelargestseasonalvariationofthediurnalfluxisobservedwiththehigh-latitudeme- teor radar. The investigations show a variation in the sources with both latitude and timeofday. TheEISCATUHFsystemandthehigh-latitudemeteorradararelocatedclosetothe ArcticCircle. SuchageographicalpositionmeansthatzenithpointstowardstheNorth EclipticPole(NEP)onceeverydayallyearround. Thisparticulargeometryallowsthe meteoroid influx from the north ecliptic hemisphere to be compared throughout the year as the ecliptic plane coincides with the local horizon. Considering only the hour whenNEPisclosesttozenith,theEISCATUHFheadechorateisaboutafactorofthree higheratsummersolsticethanduringtheotherseasons, afindingwhichisconsistent withthehigh-latitudemeteorradarmeasurements. KEYWORDS: meteors, meteoroids, dust, meteor radiants, meteoroid orbits, sporadic sources,radar

Description:
high-power transmitter/receiver and two remote receivers. when NEP is closest to zenith, the EISCAT UHF head echo rate is about a factor of three . 7.5 Paper V: Quantitative Comparison of a New Ab Initio Micrometeor .. Table 1: Dates and times for meteor campaigns with the EISCAT UHF system.
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