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Home , 11 Parthenope, 17 Thetis, 19 Fortuna, 20 Massalia, 29 Amphitrite, 324 Bamberga

1974AJ 7 9.1100Z reported byGehrelsetal.(1970),ofsixobjects THE ASTRONOMICALJOURNALVOLUME79,NUMBER10OCTOBER1974 photometer. Dunlap etal.(1973),andof1620Geographosby Dunlap (1974).Thephotographicpolarimetryof Veverka (1970,1971,1973),of1685Tororeportedby with previouslyunpublishedmeasurementsmadesince observations of36objectsareherepresentedalong 2.1- and0.9-mreflectors,usingaPolaroid,Vfilter,1P21 byLyot(1934)andtheearlyphotoelectric 1958. Wealsomakeuseofobservations1566Icarus AN intensivesurveyofasteroidpolarization-phase 532 532 Ast. Table I.PolarizationmeasurementsmadeattheMcDonald No. 29 51 14 10 10 10 13 © American Astronomical Society • Provided by theNASA Astrophysics Data System relationships wasbeguninApril1973.New 59 0217.44M0.921.850.95 59 0204.46 59 0204.38 58 1215.25 58 1207.29 58 1104.50 59 0217.51 58 1207.52 59 0218.33 59 0217.36 59 0215.45 59 0204.43 59 0204.21 58 1203.10 58 1022.42 58 1215.24 58 1207.40 58 1203.20 59 0205.10 58 1203.31 58 1203.16 59 0215.49 59 0204.33 58 1203.27 58 1215.19 59 0220.47 59 0217.39 Date (UT) Minor planetsandrelatedobjects.XVI.Polarimetriediameters branch asanindicatorofunconsolidatedsurfaceregoliths.Theempiricalslope-albedolawfordiffuselyreflect- Polarimetrie observationsof43asteroidsarepresented.Allobjectsshowawell-developednegativepolarization measurements weresystematicallytoosmall.Radiometricalbedosbelow5%,however,arenotconfirmedby ing solidsurfacesisreexaminedandusedtocomputepolarimetricalbedosdiametersfor30asteriods.In many casestheresultsareingoodagreementwithinfrared-radiometricdiameters;oldervisualdiameter of theasteroidpopulationcanbedividedintosilicaceousandcarbonaceousopacityclasses. negative polarizationbranch.CorrelationsbetweenB—Vcolorandpolarimetricparameterssuggestthatmost the polarimetry.Bimodalfrequencydistributionsarenotedforasteroidcolor,,anddepthof M0.9 M0.9 M2 •1 M0.9 M0.9 M0.9 M0, M0.9 M0.9 M0.9 M2 •1 M0, M0.9 M2 •1 INTRODUCTION M2 •1 M0.9 M2.1 M0.9 M2 •1 M0.9 MC.9 MC.9 M0.9 M2.1 Tel. MO.9 MO. 9 Lunar andPlanetaryLaboratory,UniversityofArizona,Tucson,Arizona85721 23.06 22.58 20.94 23.41 11.07 19.41 35.16 22.41 11.42 17.75 35.24 23.58 10.75 16.70 19.34 12.42 Phase 5.13 5.13 5.74 0.92 1.32 2.23 2.13 9.22 9.09 7.98 0.18 0.55 0.26 0.59 0.26 0.48 0.68 0.27 0.89 0.53 0.16 1.14 1.31 0.52 0.84 0.09 0.59 0.69 1.17 1.58 0.75 0.80 P % 0.82 1.58 B. Zellner,T.Gehrels,andJ.Gradie 60.0 88.0 -3.0 98.0 91.0 89.0 84.0 91.0 73.0 84.0 -2.0 93.0 69.0 63.0 77.0 94.0 76.0 91.0 91.0 98.0 89.0 2.0 9.0 1.0 1.0 7.0 1.0 (Received 3June1974) -0.09 -0.86 -0.53 -0.55 -0.26 -0.51 -0.52 -0.58 -0.25 -0.58 -0.74 -0.49 -0.22 -1.58 -0.76 -0.2 6 -0.77 -0.82 -0.68 0.95 0.46 0.09 0.15 1.14 1.31 1.57 1.17 % 1100 The observedasteroidsare generallybrighterthan use acomputerized,photon-countingversion(Serkow- made overatimespanof15yr.Beginningin1973we gives aprobableerrornot worse than±0.1%.The ski 1974,pp.161-164)ofourWollastonpolarimeter. here isthereforesomewhatlessthanhalfcompleted. necessary foradequatecoverage.Theprogramdescribed observations ofunpolarizedstandard ,are<0.05% green filters.Atotalof10-30 one-minuteintegrations vagaries oftelescopescheduling,weather,andorbital polarimetric, andspectrophotometricresultsforaster- photometric workinwhichsurfacemineralassemblages of aprecisioncomparablewithmoremoderndata. corrections forinstrumental polarization, derivedfrom of observationsspreadovertwoapparitionsisgenerally 30 objects,andtheobservedphotopolarimetricproper- preliminary polarimetricalbedosanddiametersfor polarimetric discriminantofgeometricalbedoisre- may beidentified(Chapmanelal.1973;McCordand fruition ofinfrared-radiometricsurveysinwhich delineate thepolarization-phasecurve.Dueto optimally selectedsolarphaseangleswouldsufficeto emission tosolarirradiation(e.g.,Matson1971;Jones diametersareinferredfromtheratioofthermal work byProvin(1955;seealsoDollfus1961)werenot eccentricity andinclination,perhapstwicethisnumber section below.InSec.IItheslope-albedolawasa oids isprovidedbyChapmanelal.(1975). and Morrison1974;1974),spectro- 12.5 magandareusuallyobserved inboththeblueand and compositions. ties arediscussedintermsofasteroidsurfacestructures Chapman 1975).Ananalysisofcombinedradiometric, examined. Inthethirdsectionthislawisusedtoderive available fromexistingdataarepresentedinthefirst In TablesI,II,andIIIarelistedtheobservations The morefundamentalphotopolarimetricparameters As fewasfourorfiveasteroidobservationsat Continuing polarimetricworkisstimulatedbythe I. OBSERVATIONALPARAMETERS 1974AJ 7 9.1100Z Ast. quantities listedinTableHI. and N,3.00. Palomar Mt.,HaleObservatories(observationsbyK.Serkowski); S, StewardObservatory,UniversityofArizona. for the1.5-mCatalinareflector and<0.02%forthe Planetary Laboratory,UniversityofArizona;H,MaunaKeaObservatory, UniversityofHawaii;M,McDonaldObservatory;P, fabricated rotatablereticle, alsousedasanoffset guider inR,6coordinates, thepolarimetereyepiece. 2.3-m reflectorofStewardObservatory. In thelaboratory thezero-pointofreticle isadjusted angles atanytelescopeis provided byaprecisely No. b a d c 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 1 2 2 1 1 1 1 2 2 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 Approximateeffectivewavenumbersinareasfollows:I,1.05; R2,1.20;Rl,1.46;0,1.55;V,1.79;G,1.93;B,2.30;U,2.76; Telescopesareindicatedbytheapertureinmeterspreceded one ofthefollowingsymbols:C,CatalinaStation,Lunarand AblankindicatesthattheWollastonprismwasorientedatprecomputed angleofmaximumpolarization. Theinternalerrorswherecomputedrefertothemeandeviationfrom acos20curve,andarenotdirectlycomparablewiththeerror The absolutecalibrationof polarizationposition © American Astronomical Society • Provided by theNASA Astrophysics Data System 66 10 66 10 59 04 59 04 59 66 12 66 10 66 10 66 10 59 08 66 12 66 12 66 12 66 12 66 12 66 12 71 12 71 11 72 01 72 04 72 04 72 02 72 04 59 04 72 04 59 04 59 04 66 10 59 08 59 04 66 10 59 08 66 12 66 12 66 12 66 12 66 11 66 10 66 10 66 12 66 10 66 12 71 11 66 10 66 10 66 09 72 04 66 10 66 10 66 10 66 10 66 10 66 11 67 01 67 01 67 01 67 01 69 03 67 02 67 01 67 01 67 01 66 11 66 11 66 12 66 11 66 11 69 04 71 11 72 04 Date (UT)Tel.Filt.PhaseP% Table II.Observationswiththecurrent-integratingWollastonpolarimeterdescribedbyGehrelsandTeska(1960). 02.22 13.39 17.42 17.42 17.42 13.42 13.48 13.47 13.46 13.31 13.30 13.29 02.40 30.41 28.37 13.35 13.33 27.14 03.14 06.42 13.36 13.35 27.24 27.22 03.21 01.19 17.35 17.35 17.35 19.28 19.23 19.28 19.36 01.14 28.30 13.18 13.14 13.13 19.31 26.48 13.23 13.22 13.10 15.21 19.39 18.44 19.46 19.42 18.50 18.46 30.39 30.35 30.33 01.48 19.50 19.48 08.42 30.44 30.42 30.30 16.39 01.18 28.53 14.50 16.48 16.46 16.43 16.41 13.51 13.37 M2.1 M2.1 M2 •1 Cl.5 M2.1 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 52.3 M2 •1 M2 •1 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 M2 •1 M2.1 M2.1 M2.1 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 52.3 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 52.3 V B G U 0 U G R2 B B R2 B B B U B G I 0 B 0 I 0 R2 G G G R2 B B B N R2 B B B B B I I I 20.92 20.91 21.23 11.07 11.07 20.91 20.91 20.91 11.07 21.73 23.08 23.08 23.08 20.71 05.44 20.43 14.99 15.86 20.24 11.43 11.82 11.43 11.43 21.49 21.48 21.46 21.46 21.47 21.45 27.48 25.92 28.70 28.70 19.60 28.70 17.14 28.71 28.71 28.71 28.71 21.47 27.23 27.23 27.24 27.24 27.24 15.09 17.81 17.99 17.09 4.25 4.25 4.22 4.23 4.24 4.22 4.22 9.48 9.50 9.53 9.51 9.52 6.83 6.85 6.84 6.84 6.83 2.33 8.86 6.85 0.60 0.68 0.86 0.51 0.31 1.58 1.58 1.49 0.40 0.92 1.67 1.39 0.71 0.72 0.56 1.58 1.64 0.58 0.82 1.28 1.45 1.47 '0.41 0.57 0.57 1.68 0.88 1.30 1.28 1.30 1.40 1.42 0.35 0.19 0.22 0.57 0.42 0.48 0.66 0.66 1.23 0.47 0.79 1.36 1.35 0.91 0.75 0.84 0.69 1.62 0.85 0.73 0.69 0.71 0.85 0.40 0.65 0.90 0. 7 7 0.57 0.84 0.49 0.37 0.60 0.10 0.21 1.11 0.56 1.07 1. 16 0.04 0.14 0.16 0.16 0.02 0.17 0.17 0.05 0.02 0.05 0,04 0.02 0.10 0.09 0.13 0.07 0.02 0.03 0.02 0.03 0.09 -41.0 0.08 1.0 0.11 0.17 0.09 0.19 0.20 0.12 0.22 -20 0.06 0.40 109.0 0.07 98.0 0.12 101.0 0.09 0.08 0.08 0.18 0.17 0.23 0.15 94.0 0.04 0.28 0.11 102.9 0.09 94.0 0.07 0.07 MINOR .XVI. -14.0 100.0 104.0 92.0 -6.0 95.0 94.0 -1.3 -3.4 91.7 82.6 16.2 84.9 91.5 89.1 86.3 85.1 90.0 89.5 -2.0 23.0 89*0 66.0 88.9 -3.0 -4.0 93.8 96.6 89.8 79.6 -3.0 -2.0 -4.0 97.0 94.0 11.6 90.8 82.0 14.6 88.0 81.0 10.0 0.5 5.9 0.2 5.0 1.2 1.3 1.3 0.0 2.0 8.0 4.0 7.0 3.5 4.0 8.0 8.0 7.0 0 -1.56 -1.56 -1.49 -1.39 -1.61 -1.62 -1.56 -1.28 -1.45 -1.46 -1.28 -1.68 -0.72 -0.56 -0.54 -0.82 -1.29 -0.88 -1.23 -1.31 -0.30 -0.62 -1.35 -0.84 -0.70 -0.81 -0.20 -0.10 -0.3 7 -1.15 -0.76 -0.53 -0.68 -0.47 -0.56 0.84 0.51 0.67 0.80 0.51 0.40 0.92 0.71 0.57 0.40 1.30 1.38 1.42 0.42 0.63 0.47 0.57 0.42 0.03 0.22 0.60 0.84 0.78 0.74 0.87 0.65 0.82 0.40 0.60 0.63 1.62 0.70 0.85 0.35 1.07 position angles.Anindependent checkisprovidedby orientation thusnotedfora true north-sôuthlinegives Wollaston prism.Thenatthe telescopeastarimageis the observed position anglesforthemore highly- directly thecorrectionfrom instrumental toequatorial driven backandforthindeclination, andthereticle to coincideinazimuthwith theopticaxisof Ast. 192 192 192 433 433 433 433 433 433 324 192 433 324 324 324 324 192 192 192 433 192 433 433 433 433 433 433 433 433 433 433 433 433 511 877 877 877 No. 4 4 72 0427.29 72 0427.31 72 0403.18 59 04 72 0505.24 67 04 59 04 67 04 67 04 67 04 59 04 59 04 59 04 67 04 67 04 67 04 67 06 67 06 67 06 67 06 67 06 67 06 67 06 71 11 59 08 72 09 72 08 59 08 59 08 59 08 68 01 68 01 68 01 59 08 59 08 59 08 68 01 72 0611.21 72 0511.18 72 0417.29 59 08 68 01 68 01 72 0622.21 72 0505.18 68 01 68 01 68 01 68 01 68 01 72 07 72 07 72 06 72 08 72 08 72 08 72 08 72 08 69 1105.29 72 08 70 0121.27 69 1208.27 72 0809.31H2.2 72 0820.60H2.2 Date (UT)Tel.Filt.PhaseP%e n 28.19 25.13 25.13 28.19 28.19 18.41 18.39 18.40 09.29 18.33 09.34 09.28 09.30 18.34 18.35 04.42 04.42 06.55 28.08 09.33 09.35 09.37 18.37 04.42 04.42 31.53 07.43 05.33 07.43 08.44 05.38 05.35 05.42 06.36 05.55 05.52 06.38 06.47 06.44 06.53 06.50 03.55 08.58 20.46 03.55 25.51 09.34 09.35 20.43 31.39 Cl.5 Cl.5 M2 •1 Cl.5 Cl.5 M2.1 M2 •1 M2.1 M2 •1 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 M2.1 M2 •1 M2.1 HO.6 H2.2 Cl.5 M2 •1 M2 •1 M2 •1 M2.1 M2.1 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 S2.3 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 H2.2 H2.2 H2.2 Cl.5 H2.2 H2.2 S2.3 H2.2 H2.2 H2.2 Cl.5 Cl.5 S2.3 U V 0 U G R2 B 0 N G R2 G U B I G B N I V RI V U B V V I U B RI O R2 G B B B B U O B R2 G U B G G B B B B B B B 24.83 24.82 24.82 24.83 24.82 12.15 14.76 14.76 14.76 14.78 14.77 14.78 23.32 13.51 14.77 23.29 23.32 13.50 13.51 31.80 31.80 13.53 13.54 13.52 31.80 13.52 31.45 31.71 31.80 31.45 31.32 53.20 53.20 53.10 53.10 53.20 53.20 53.20 16.55 15.62 10.07 53.10 53.10 28.94 32.92 53.10 53.10 22.59 17.82 43.30 14.36 14.36 17.81 21.22 42.04 3.920.04-1.2 36.77 9.88 2.48 9.89 4.16 8.57 4.73 1.060.0593.3-1.06 8.45 8.94 0.55 0.66 0.77 0.76 0.10 0.22 0.48 0.33 0.51 0.31 0.41 0.59 0.54 0.43 0.69 0.62 0.74 G .62 0.77 0.43 0.58 0.55 0.15 0.30 0.12 0.11 0.90 0.97 1.20 0.87 0.90 1.15 1.23 1.22 2.52 8.17 3.53 1.01 3.30 2.68 3.49 1.47 3.75 5.43 3.88 1.00 1.09 1.41 3.10 0.07 0.17 5.53 0.23 0.39 1.08 0.66 0.75 0.16 1.10 .24 .17 0.05 0.03 0.06 0.05 0.08 0.03 0.05 0.07 0.07 0.03 0.05 0.07 0.10 0.02 0.08 0.14 0.06 0.02 0.05 0.10 0.11 0.06 0.23 0.18 0.14 0.06 0.42 0.28 0.24 0.74 0.17 0.13 0.10 0.36 0.34 0.12 0.16 0.08 0.09 0.17 0.12 0.06 0.06 0.08 0.31 0.17 -0.3 0.02 0.0 0.11 -5.7 -14.0 103.2 106.1 92.0 87.0 90.0 88.0 38.0 91.2 24.0 90.2 88.2 86.2 13.0 86.2 95.0 11.0 81.0 94.0 93.0 84.0 80.0 82.0 82.0 82.0 -2.4 91.5 91.0 13.0 -1.6 92.0 92.0 88.0 -2.4 -1.1 -3.0 -8*0 14.5 -3.9 93.0 91.9 72.7 8.0 4.0 7.0 2.0 6.0 0.8 0.2 0.7 2.0 2.4 1.0 1.0 -0.77 -0.55 -0.66 -0.76 -0.43 -0.51 -0.40 -0.54 -0.76 -0.68 -0.59 -0.72 -0.59 -0.53 -0.62 -0.40 -0,56 -0.29 -1.09 -1.41 -1.47 -0.87 -1.00 1101 -0.23 -0.34 -0.14 -0.75 -0.15 -0.66 0.30 0.09 0.43 0.08 0.15 0.15 P. * 0.12 0.11 0.95 0.90 0.90 1.16 1.11 2.52 2.68 3.48 7.91 3.88 3.52 1.00 1.08 1.15 3.30 3.75 5.43 3.09 5.53 0.07 1.08 1.09 0.08 2.24 3.11 1974AJ 7 9.1100Z Table III.Observationswiththenewphoton-countingWollastonpolarimeter,inwhichpolarizationmodulationisprovidedbya 1102 © American Astronomical Society • Provided by theNASA Astrophysics Data System Ast. No. 73 05 73 05 73 05 73 05 73 05 73 04 73 04 73 04 73 04 73 04 73 05 73 05 73 05 73 05 73 05 73 05 73 04 73 06 73 06 73 06 73 06 73 05 73 06 73 06 73 06 73 06 73 06 73 04 73 04 73 08 73 04 73 04 74 04 73 08 73 08 73 08 73 06 73 06 73 0406*44 73 0413*22 73 0731.29 73 0515*39 73 0808*24 73 12 73 10 73 10 73 10 73 04 73 04 73 04 73 12 73 12 74 02 74 02 73 12 73 12 73 12 74 04 74 04 74 04 74 02 73 12 73 12 73 12 73 12 74 04 73 08 74 04 73 09 73 08 73 08 74 04 73 10 73 09 74 04 74 04 73 12 73 10 73 12 74 01 73 12 73 10 73 12 73 12 73 12 74 04 74 04 74 02 74 02 74 01 73 12 74 01 74 01 74 04 74 04 74 04 73 0912.44 73 1006*51 73 0912.48 73 0912*46 Date ,(UT)Tel.Flit.PhaseP*e% 08*39 02*39 02.39 02.39 06*46 06*45 08*40 08.39 22*38 22.37 02*38 02.37 03*36 03.36 11*28 13*44 13.44 22*14 26*17 14.37 14*36 13*38 13*38 11*29 06*40 26*18 26*17 22.34 11.35 11.34 03*32 22*48 07.23 13.18 13.17 26*22 22*21 14*38 06*14 25.51 06*15 27.52 25.53 28*56 13*16 10.55 10*54 01.38 22.38 22*36 30*49 28*58 28*57 05*38 01.39 22*35 30.53 30.53 30.50 ¿6*25 05.44 05.42 05*40 30*52 08*41 07*30 22*42 08.39 07*31 10.22 07.25 07*24 19*45 10.20 22*33 28*53 28*50 25*49 29*14 29*14 29.23 28*26 19*48 01*22 01*20 22*31 29.25 19*42 22*22 22*20 19*43 Cl.5 Cl.5 Cl.5 Cl *5 Cl.5 Cl *5 Cl.5 Cl.5 Cl*5 S2 •3 S2*3 Cl*5 C1.5 S2.3 S2 •3 S2.3 S2* 3 Cl*5 Cl.5 Cl.5 S2.3 Cl.5 Cl.5 C1.5 S0.5 SO* 5 Cl*5 Cl.5 Cl.5 S2.3 Cl.5 Cl.5 S2*3 Cl.5 Cl.5 Cl.5 S2.3 S2.3 0*5 Cl.5 S2.3 S2*3 Cl.5 C1.5 Cl.5 S2.3 SO* 5 Cl.5 Cl*5 S2*3 S2 *3 S2*3 Cl.5 Cl.5 Cl.5 Cl. 5 Cl.5 Cl.5 Cl •5 Cl.5 Cl.5 Cl.5 Cl.5 Cl •5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 C1.5 S2.3 S2.3 S2.3 S2.3 S2.3 S2.3 S2.3 S2.3 Cl.5 S2.3 Cl. 5 C1.5 C1.5 Cl.5 C1.5 Cl.5 Cl.5 C1.5 Cl.5 Cl.5 C1.5 C1.5 Cl. 5 C1.5 C1.5 C1.5 C1.5 Cl.5 S2.3 Cl •5 rapidly spinningachromatichalf-waveplate.SymbolsareasinTableII. 17.31 12.05 12.05 15.11 15.11 18.67 18.67 12.05 17.31 20.60 14.79 13.48 13.97 13.97 17.59 18.88 19.85 18.82 17.35 18.55 20.12 20.12 15.12 15.97 16.13 17.09 24.84 23.83 23.83 19.24 24.84 24.84 17.77 24.84 24.84 24.84 24.84 17.77 24.84 18*29 21.81 17.80 17.80 17.81 21.81 21.22 21.39 16.87 16.88 24.44 24.44 21.57 21.57 24.07 15.89 11.42 II. 4 2 15.89 16.41 16.42 9.95 9.95 9.95 21.42 8.88 8.88 21.56 21.42 19.28 19.28 4.33 7.69 7.69 8.08 8.08 4.33 32.23 32.72 32.72 9.97 9.96 9.96 32.72 I. 30 1.30 1.11 1.11 8.79 ZELLNER, GEHRELS,ANDGRADIE 5.91 7.55 5.95 5.05 5.95 7.55 5.58 5.58 8.43 7.77 7.76 8.44 0.74 0.80 0.20 0.23 0.15 0.12 1.22 0.56 1.54 1.18 1.29 0.67 0.69 0.63 1.64 1.62 1.62 1.66 1.60 0.82 0.64 1.66 1.72 1.67 0.71 0.15 0.89 0.83 1.50 1.44 0.42 0.10 1.51 1.58 1.53 0.13 0.16 0.17 0.74 0.51 0.37 tt.28 0.29 0.38 0.26 0.21 0.03 0.06 0.26 0.24 0.26 0.18 0.16 0.23 0.21 0.21 0.13 0.70 0.22 0.19 0.23 0.26 0.66 0.79 0.80 0.74 0.68 0.56 0.28 0.71 0.33 0.27 0.60 0.20 0.21 0.36 0.63 0.21 0.32 0.27 0.23 0.80 0.39 0.37 0.30 0.46 0.48 0.33 0.75 0.82 0.13 0.06 0.75 0.03 0.02 0.11 1.98 0.21 1.54 0.06 1.22 0.06 1.37 0.05 ' 0.06 0.04 0.02 0.05 0.03 0.04 0.06 0.03 0.01 0.02 0.04 0.07 0.12 0.04 0.04 0.03 0.04 0.04 0.03 0.05 0.13 0.02 0.03 0.04 0.05 0.15 0.04 0.06 0.07 0.03 0.03 0.03 0.02 0.03 0.04 0.12 84.8 0.08 -10.9 0.09 0.07 0.10 0.17 0.16 0.13 0.04 0.07 0.11 0.07 0.04 0.03 0.02 0.02 0.13 0.05 0.06 0.03 0.08 0.05 0.05 0.02 0.01 0.02 0.02 0.05 0.06 0.14 0.07 0.02 0.01 0.05 0.01 0.14 0.14 3.2 0.20 -17.0 0.15 -21.4 0.12 0.11 0.14 0.15 0.10 0.08 0.18 0.15 0.15 0.16 0.06 0.08 0.15 0.06 0.07 0.02 0.02 0.04 0.17 0.17 0.12 0.11 121.3 90.1 90.0 89.7 90.5 90.5 89.7 91.8 92.2 91.0 89.2 89.5 91.6 90.5 89.6 88.9 90.0 91.9 89.9 89.9 89.8 89.2 90.0 -0.1 91.4 92.2 94.5 92.7 90.9 92.6 82.0 88.5 11.5 91.1 90.8 89.6 96.1 87.8 89.9 94.6 95.1 91.2 90.6 91.9 84.5 86.5 86.1 90.4 94.0 91.5 84.2 -1.4 -0.4 -3.5 -0.9 -0.8 85.2 87.5 94.8 92.4 90.6 85.6 -4.8 91.9 92.4 92.5 88.7 -1.2 2.2 13.5 17.8 1.4 0.3 0.1 0.2 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.0 0.9 -0.80 -0.20 -0.23 -1.29 -1.22 -0.74 -1.66 -1.60 -1.54 -1.18 -1.62 -1.62 -1.72 -1.64 -1.67 -0.63 -0.56 -1.66 -1.44 -0.67 -0.69 -0.70 -1.51 -1.58 -1.53 -1.50 -0.83 -0.88 -0.82 -0.15 -0.17 -0.51 -0.17 -0.37 -0.74 -0.29 -0.21 -0.03 -0.06 -0.23 -0.26 -0.26 -0.28 -0.22 -0.28 -0.71 -0.78 -0.79 -0.73 -0.67 -0.69 -0.56 -0.66 -0.20 -0.21 -0.36 -0.63 -0.60 -0.32 0.14 0.12 -0.13 -0.06 -0.75 -0.75 -0.82 -0.80 -0.39 -0.37 0.64 0.10 0.15 0.42 0.12 0.16 0.26 0.18 0.21 0.13 0.23 0.21 0.19 0.23 0.26 0.21 0.22 0.24 0.23 0.46 0.48 0.32 0.27 0.30 0.02 0.10 0.02 1.22 1.54 1.98 1.37 Ast. No. 11 11 11 11 11 11 . 11 11 11 12 12 12 12 15 15 15 15 15 15 15 15 15 17 17 17 17 17 17 17 17 19 19 19 19 19 19 20 19 20 20 20 20 20 73 0413.36 73 0406.38 73 0413.36 73 0406.39 73 0422.31 73 0604.21 73 0502.35 73 0502.35 73 0723.19 73 0604.21 73 0723.20 73 0722.23 73 04 73 04 73 05 73 05 73 05 73 05 73 05 73 05 73 05 73 06 73 05 73 05 73 0508.33 73 06 73 06 73 0513.35 73 0513.34 73 0514.33 73 0731.20 73 0722.25 73 0823.20 73 0808.21 73 0808.21 74 04.01.34 74 0401.35 74 0410.41 74 0426.29 74 02 74 03 74 03 74 02 74 04 74 04 74 04 74 04 74 04 73 0413.45 73 0502.44 73 0422.40 Date (UT) 73 0508.42 73 0514.38 73 0513.40 73 0723.28 73 0723.30 73 0508.27 73 0511.22 73 0511.22 73 0508.28 73 0604.34 73 0604.35 73 0627.25 74 0222.41 74 0326.35 74 0222.43 74 0326.37 74 0412.40 74 0401.42 10 07.45 10 C6.52 10 07.45 10 31.25 10 07.52 10 07.47 01 16.41 01 16.40 11 04.39 10 27.45 01 29.20 01 16.42 12 07.28 11 04.40 01 30.30 01 29.20 12 28.34 12 28.33 12 07.30 12 07.29 02 22.27 02 02.25 01 30.31 12 28.34 04 01.14 02 22.30 02 22.29 02 02.27 04 01.16 22.27 08.25 08.25 02.33 02.33 13.33 27.16 14.29 11.18 27.18 15.25 13.23 13.21 11.19 02.44 02.41 05.26 01.24 27.25 27.24 05.28 22.15 22.16 S2.3 52.3 52.3 52.3 52.3 SO.5 Cl.5 S2.3 S2.3 SO .5 Cl.5 Cl.5 Cl.5 S2 •3 S2.3 S2.3 Cl.5 Cl. 5 Cl.5 Tel. Filt.Phase Cl.5 C1 •5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 S2.3 S2.3 Cl.5 Cl.5 Cl.5 PI.5 PI.5 Cl.5 Cl.5 PI.5 Cl.5 S2.3 Cl.5 52.3 52.3 Cl.5 Cl.5 Cl.5 Cl.5 S2.3 52.3 Cl.5 Cl.5 Cl.5 Cl.5 S2.3 Cl.5 PI.5 Cl.5 S2.3 S2.3 S2.3 Cl.5 Cl.5 Cl.5 S2.3 Cl.5 C1.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 C1.5 S2.3 Cl.5 S2.3 PI.5 C1.5 PI. 5 S2.3 S2.3 S2.3 S2.3 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 32.23 29.32 32.14 32.15 32.15 32.15 27.33 27.33 28.46 13.41 13.42 13.41 24.11 11.04 26.90 26.90 24.12 24.11 17.44 11.04 11.03 - 17.44 17.00 17.00 18.58 18.57 20.29 23.24 23.29 20.29 10.37 23.24 10.37 12.44 23.10 17.61 15.89 15.89 23.30 18.37 17.61 23.30 18.86 18.37 19.32 18.86 22.53 25.25 24.19 26.31 25.25 1.64 1.64 15.56 0.490.12100.7 1.64 4.58 4.58 3.93 6.45 3.93 13.97 27.27 16.05 15.19 13.97 18.76 16.06 24.80 26.39 18.76 23.53 22.00 22.27 8.91 11.64 11.64 20.07 9.66 0.69 16.13 16.13 23.17 23.17 7.39 7.51 16.82 16.82 9.20 0.670.2084.7 5.72 0.580.0490.2 5.72 0.620.0594.9 10.61 14.56 8.01 8.01 7.36 8.51 8.51 7.36 .52 0.85 0.87 0.72 0.56 1.3Û 1.75 1.93 0.48 0.58 0.62 1.20 0.68 0.36 0.36 0.38 1.18 0.68 0.80 0.36 0.37 0.13 0.31 0.64 0.25 0.30 0.31 0.41 0.85 0.57 0.54 0.66 0.54 1.04 0.56 0.57 0.03 0.04 0.54 0.71 0.72 0.48 0.52 0.46 0.38 0.21 0.39 0.22 0.23 0.33 0.22 0.29 0.22 0.48 0.74 0.08 0.67 0.85 0.69 0.79 0.96 0.69 0.71 0.51 0.50 0.40 0.45 0.41 0.31 0.25 0.81 0.55 0.85 0.26 0.40 0.64 0.17 0.57 1.67 0.48 1.65 1.56 1.61 0.29 1.59 0.39 1.50 0.18 0.27 0.38 0.63 71 0.10 0.05 0.31 0.26 0.06 0.24 0.16 0.05 0.08 0.04 0.08 0.02 0.02 0.08 0.04 0.07 O.C<* 0.10 0.05 0.06 0.04 0.02 0.05 91.9 0.28 5.4 0.03 -0.6 0.10 -7.9 0.15 100.2 0.04 0.9 0.02 0.1 0.03 0.05 0.10 0.05 0.08 0.14 0.12 ' 0.10 0.18 0.13 0.25 0.10 0.11 0.05 0.14 0.06 0.05 0.14 0.06 0.08 0.14 Ü.12 U.2C 0.11 0.12 0.11 0.06 0.15 0.08 0.11 0.09 0.11 0.06 0.20 0.13 0.15 0.08 0.07 0.04 0.04 0.05 0.11 0.15 0.14 1.2 0.19 -4.9 0.14 91.7 0«18 -9.8 0.15 -1.0 0.07 -1.6 0.19 2.3 0.10 91.1 0.07 88.7 0.15 91.4 0.07 88.7 0.42 87.0 0.36 92.1 0.16 90.0 0.06 0.04 0.12 93.9 0.04 88.6 0.12 95.9 0.07 88.6 -1.4 •40.0 -C.3 -1.5 91.1 91.3 89.0 94.4 86.8 88.5 90.7 90.8 90.7 89.4 91.9 87.1 87.6 90.2 91.8 89.5 86.0 90.5 90.4 -7.8 91.0 90.0 88.0 92.4 88.4 13.2 10.8 94.5 89.0 91.6 92.0 89.3 90.1 -1.3 —4.6 80.6 -2.0 0.9 0.6 88.1 2.9 88.1 88.1 91.5 0.7 15.4 0.4 1.2 90.4 93.4 93.2 89.1 90.7 88.6 86.2 87.2 90.8 9.7 6.1 -5.2 0.7 1.1 2.8 1.2 -0.62 -0.36 -0.36 -0.38 -0.48 -0.58 -0.68 -0.68 -0.80 -0.37 -0.36 -0.12 -0.30 -0.31 -0.25 -0.54 -0.65- -0.57 -0.54 -0.56 -0.57 -0.54 -0.72 -0.71 -0.52 -0.48 -0.27 -0.23 -0.33 -0.39 -0.46 -0.38 -0.21 -0.7*. -0.67 -0.71 -0.69 -0.58 0.85 0.87 1.75 1.93 -0.61 -0.66 0.56 1.30 0.72 1.18 1.20 -0.46 -0.71 0.41 -0.51 -0.50 -0.69 0.31 0.82 -0.45 0.64 -0.40 -0.24 -0.31 -0.41 1.02 0.40 0.03 0.24 0.39 0.01 -0.57 -0.64 -1.56 -1.61 -1.67 -1.65 -1.49 -1.59 -0.47 0.22 0.22 0.68 -0.27 0.19 -0.18 0.79 0.85 0.43 -0.63 -0.38 0.96 0.81 0.84 0.55 0.17 0.40 0.24 0.38 0*29 1974AJ 7 9.1100Z iiiey arenotdirectlycomparable to theerrorquantitieslistedinTableII. Interna,! errorsrefertothermsrepeatability ofindividualpolarizationdeterminationsan © American Astronomical Society • Provided by theNASA Astrophysics Data System Ast. 63 63 63 63 63 63 63 63 42 42 51 51 51 51 42 51 42 39 39 39 39 23 39 39 39 39 31 31 27 27 27 23 23 23 23 23 40 40 40 39 39 39 39 39 23 23 40 40 40 40 40 39 39 39 23 23 21 21 40 40 21 21 21 2* 21 21 40 40 40 39 39 39 21 21 21 21 21 21 21 21 20 20 No. 73 0823 73 0822 73 0731 73 0822 73 0731 73 0604 73 0422 73 1229 73 1229 73 0508 74 0116 73 1231 73 1229 74 0410 74 0326 74 03 74 0326 74 04 74 04 74 03 73 10 73 0422 73 10 73 09 73 09 73 08 73 06 74 0410 74 0410 73 0508 73 0413 73 06 73 05 73 05 73 06 73 10 73 10 73 08 73 08 73 07 73 07 73 06 73 06 73 06 73 06 73 06 73 05 73 05 73 04 73 06 73 06 73 06 73 08 73 04 73 04 73 10 73 10 73 09 73 09 73 09 73 09 73 08 73 08 73 08 73 06 73 06 73 07 73 07 73 06 73 11 73 10 73 05 73 05 73 05 73 08 73 07 73 11 73 05 73 08 73 08 73 07 73 08 73 05 74 0422.38 74 0422*36 73 10 73 10 Date (UT)Tel.Filt.PhaseP% Cl*5 Cl.5 6.20 6.21 0.10 0.10 MINOR PLANETS.XVI. 09 88 09 90 15 89 10 98 11 89 10 101 08 90 05 87 09 89 20 9 06 90 06 89 06 91 07 87 05 111 07 89 23 -1 34 -16 26 -10 18 -43 13 -6 11 3 14 -7 14 -0 19 1 19 1 -0 90 89 89 90 0 Table III{continued) 887 887 887 887 887 877 887 887 887 887 654 887 654 654 654 654 654 654 532 532 532 532 532 532 511 511 511 511 511 511 511 511 511 511 511 511 511 511 511 349 511 511 511 349 349 349 324 324 324 324 324 324 324 324 Ast. 324 324 1 41 141 141 141 141 141 141 1 41 141 141 1 4 1 41 141 141 141 1 4 141 141 139 139 139 139 139 No. 74 01 74 01 74 01 74 01 74 01 73 12 73 12 73 12 7312 73 11 73 11 74 0130.27 74 0130.27 74 0115.35 74 0115.34 73 1231.19 73 1231.16 73 1231.11 73 0603.15 73 0513.17 73 0511.15 73 0508.22 73 0422.33 73 0413.32 74 Cl 73 12 73 12 73 10 73 10 7 310 73 09 73 09 73 08 73 08 73 08 73 08 73 03 73 08 7 308 73 07 74 0326.31 73 08 73 07 74 0401.27 74 0326.30 73 08 73 08 74 0401.29 73 08 73 08 73 08 73 08 73 12 73 11 73 10 73 08 7 30-4 73 04 73 12 73 12 73 10 73 10 73 10 73 04 73 12 73 11 73 10 73 10 73 10 73 09 73 10 73 09 73 08 73 08 74 0422.26 74 0422.28 74 0410.25 74 0405.35 74 0405.32 74 G116.44 73 1231.45 73 1231.29 73 0919.38 73 0826.42 73 1007.15 73 1007.13 73 0826.25 73 1008.19 73 0826.27 Date (UT) 16.49 19.46 31.37 28.47 28.45 16.49 16.30 16.30 30.30 16.40 16.33 29.22 28.23 24.28 07.27 27.38 27.44 30.09 23.41 16.14 27.40 23.39 22.38 22.36 06.45 06.42 31.45 31.44 28.14 19.41 27.19 26.19 08.20 06.51 22.18 22.16 08.18 22.45 07.18 06.50 29.16 29.12 07.21 04.31 25.C9 24.19 08.31 26.21 24.19 08.27 16.18 08.25 06.23 26.39 23.34 12.30 19.28 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 C1 •5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 S2.3 Cl.5 S2.3 52.3 Cl.5 Cl.5 Cl.5 Cl .5 Cl.5 Cl.5 50.5 52.3 Cl.5 Cl.5 Cl.5 Cl.5 52.3 Cl.5 52.3 52.3 52.3 52.3 Cl.5 Cl.5 Cl.5 52.3 Cl.5 52.3 52.3 52.3 52.3 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 52.3 52.3 Cl.5 52.3 52.3 52.3 Cl.5 52.3 52.3 Cl .5 Cl.5 Cl.5 Cl.5 Cl.5 Cl.5 Tel. Filt.PhaseP% are behevedtobehighlyconservative. 12.41 27.52 27.52 28.53 23.57 13.68 15.74 28.53 0 15.76 23.56 16.53 26.33 25.19 24.97 16.52 24.63 21.98 16.50 19.89 2C.88 20.52 20.5 7 24.62 11.83 24.76 24.46 23.75 20.24 13.39 16.44 16.45 17.07 19.33 19.33 23.75 20.53 20.53 17.07 17.22 17.22 18.96 11.33 0.38 20.24 27.64 27.11 18.95 11.33 0.40 27.64 27.12 24.28 19.08 21.41 27.02 26.98 26.98 20.00 18.3» 18.22 17.82 17.82 11.59 11.57 11.56 11.57 14.56 15.75 11.34 15.62 16.94 19.99 8.47 5.92 5.92 5.75 5.75 9.93 8 •1 8.47 9.56 0.32 9.56 0.37 6.00 6.84 2.89 8.17 7.25 7.32 0.75 0.65 0.70 0.65 0.68 0.54 0.43 0.31 0.28 0.62 0.88 2.73 0.83 0.91 2.81 0.99 1.16 0.70 0.64 0.59 0.48 1.32 0.18 0.02 J. 2 C 0.57 0.7 CC.1496.5 0.78 0.61 0.1390.2 0. 10 1 .e J •70 0.11 I. 6 7 1.66 1.48 1.23 0.05 U.1Ü39.1 0.02 1.68 1.47 2.14 0.73 0.82 1.53 1.12 0.15 2.15 0.95 0.94 0.89 1.19 2.23 2.15 0.07 0.52 1.76 0.82 0.81 1.44 1.72 1.78 1.26 1.11 1.43 1.66 1.51 1.38 1.18 .68 .89 .Cl .76 0.08 0.10 0.10 0.03 0.13 0.20 0.12 0.12 0.18 0.65 0.50 0.22 0.11 0.14 0.06 0.18 0.25 0.12 0.10 0.09 0.09 0.05 0.08 0.03 ».09 83.7- C.12 90.4- ».17 91.6- u.l6 7 ».20 C.17 0.06 95.9 0.04 93.9 0.13 92.2 O.09 0.08 0.17 0.18 94.4 0.37 -16.8 0.27 -0.5 0.23 -0.9 0.08 >5.6-0.09 0.15 2.3 0.14 0.35 103. 0.17 1. >-.16 -1. 0.17 88. 0.03 -7. 0.27 -1. 0.32 1. 0.21 2. 0.16 2. 0.10 -29. O.U9 88. 0.12 91. o•20 86. 0.38 86. 0.10 89.2-1.72 0*10 0.12 0.14 0,09 0.14 .25 -20.60.12 .19 2.00.24 .13 0.20.20 .57 90.9-1.61 » u986.1-1.65 . 1690.2—G•8** .11 .09 90.6-0.52 .14 89.1-0•8 .10 88.5-0.41 . 12 15 32 88.4 90.1 91.3 89.3 92.4 87.0 -1.2 -2.2 85.6 -0.2 88.3 90.6 91.6 -2.1 -0.4 98.0 91.2 87.2 32.0 -1.2 -1.7 96.3 90.5 93.1 90.6 90.9 -1.18 2.1 0.6 1.2 0.2 4.9 1.4 -0.65 -0.75 -0.65 -0.68 -0.70 -0.54 -0.43 -0.31 -0.28 -0.88 -1.32 -0.99 -0.02 -»>.5 7 —0.40 -0.32 -».78 —0.68 -0.55 -0.13 -0.37 -0.37 -0.61 -0.19 -0.02 -0.36 -1.11 -0.82 0.62 2.61 2.73 0.83 0.91 1.16 0.70 0.64 0.59 0.48 0.18 1.62 1.48 1.23 0.04 0.01 0.10 2.13 1.40 1.47 2.13 0.95 0.68 1.12 0.14 0.73 0.82 0.76 1.53 1.19 0.04 0.94 0.88 1.75 1.44 1.78 1.43 1.66 1.51 1.37 1103 1974AJ 7 9.1100Z a, circles inthegreenorvisual. methods arefoundtoagreewithin±0?!. polarized solarsystemobjects.Thetwocalibration While notwoobjectshavebeenfoundtoexhibit Laetitia, and(433)Eros,but possiblerotationand night andfromyeartoyear.Apparentlygenuinescatter identical curves,theCeresdataaretypicalinshowing normal totheplaneofscattering. untrustworthy. Inthedatalistedherethiseffectis its magnitudeisinflatedandpositionanglebecomes - plane.Whenthemeasuredpolarizationis polarization changes sign,andtheslope h,usually positive quantity),theinversion angleawherethe reported here. large-amplitude lightcurves,notably(7)Iris,(39) on theorderof±0.1%wasfoundforafewobjectswith remarkably smoothandreproduciblefromnightto lineai ascendingbranch.Theobservationstendtobe the anglebetweenobservedpositionand defined bythereductionP=bscos20,wheredis that is,thedominantelectricvectorrespectively, a rapiddroptonegativepolarizationsatsmallphase corrected statisticallyandthepolarizationsignis comparable toorsmallerthanthephotonnoiselevel, either perpendiculartoorcontainedintheSun-asteroid either positiveor“negative”withinourerrorlimits; 1 .Filledcirclesrepresentobservationsinbluelight;open the dépthPmofnegative branch(thoughtofasa aspect effectsarenotspecifically identifiedinthedata angles andaratherflatminimumfollowedbynearly 1104 (1) Ceres,oneofthebest-observedasteroidstodate. 0 r0 m Fig. 1.Polarizationasafunctionofsolarphaseanglefor In allasteroiddatawefindthepolarizationtobe The polarimetricparameters ofprimaryinterestare Figure 1illustratesthepolarization-phasecurvefor © American Astronomical Society • Provided by theNASA Astrophysics Data System ZELL NER,GEHRLS,ANDGRADIE provisional andbasedondatathatstillareincomplete. phase angleslargerthan15°,usingeitherastraight IV-VII. Inmanycasesthelistedparametersare inspection fromobservationsbetween5°and11°phase. line oraparabolaasseemsappropriate.Thecurvature fragmentary dataaregivenwithaquestionmark(?). data areindicatedbyacolon(:),andresultsfrom invariably isfoundtobesmall.Piestimatedby from thefittedline. for whichradiometricorpolarimetricdataareknown was constructedforthispurposeandincludesall imetric andradiometricdata(Sec.Ill)requires an exclamationmark(!),whilenoisyordiscordant Especially well-determinedquantitiesaregivenwith and oioarefoundbyaleast-squaresfittodatapointsat parabola forthedeterminationof aandh;eisthermsdeviation objects forwhichB,Vphotometrycouldbefoundand at theinversionangle.Inthissurveyquantitiesh measured inpercentperdegreeoftheascendingbranch to exist. accurate absolutemagnitudesandcolors.TableVIII distribution isrevealedinFig.2.AsshownSec.Ill, a similarbimodalityisseeninpolarimetricquantities. 1620 Geographos 1685 Toro 1566 Icarus mn 0 ar 887 Alinda 349 Dembowska 654 Zelinda 141 Lumen 139 Juewa iV isthenumberofdatapoints fittedbyastraightlineor 51 Nemausa 42 Isis 31 Euphrosyne 23 Thalia 89 Julia 63 Ausonia The polarimetricresultsaresummarizedinTables The determinationofasteroiddiametersfrompolar- A distinctlybimodalcharacteroftheasteroidB—V 9 1 Ceres Object Hebe Juno Pallas Iris Astraea Table IV.Asteroidpolarimetricparameters measured inthebluefilter. Pmin% Ne% 0.35 0.65? 0.75? 0.70 0.55: 0.75 0.70: 0.70 0.90? 0.60? 0.70? 0.70? 0.65 0.70! 0.75? 0.60! 0.70 0.80 0.70? 0.75! 1.65 1.45 1.75 1.30? 1.25? 1.65 1.30 1.40? 1.70! 1.90? 7 0.0219.3!0.120!0.138 Ascending branch* 0.03 0.04 0.09 20.6!0.308! 0.02 0.16 0.12 0.03 0.02 0.16 0.10 0.16 0.07 21.4!0.297! 0.05 0.02 0.05 0.04 0.05 0.06 0.03 20.3 0.03 21.0 0.04 0.06 0.04 21.1 20.5 0.098 26 ? 20.2 20.8 0.104 22 ? 20 ? 22 : 24.5! 21.9? 21.2! 20.1! 20.4 20.6! 20.6 19.1 19.7 19.6 18.9 19.2: 18.8 18.3! 0.318 0.107? 0.127 0.261 0.094 0.130? 0.108? 0.171! 0.088 0.118 0.121: 0.26 ? 0.096! 0.255! 0.127 0.166 0.099 0.102! 0.099: 0.064! 0.191 0.083 Slope albedo 0.052 0.155 0.131 0.064 0.169 0.128 0.154 0.141 0.160 0.137 0.056 0.176 0.097 0.054 0.188 0.065 0.064 0.131 0.100 0.168 0.258 0.173 0.087 0.163 0.168 0.199 Blue 1974AJ 7 9.1100Z determination. properties forthecalibrationofempiricalrelationships. of asteroidpolarimetry.Untilthistheoryismorefully 1566 Icarus developed, wedependprimarilyuponlaboratoryresults crystal surfaces,seemsverypromisingforinterpretation ization fromintricatesurfacesaccordingtomultiple measurable bulkalbedo.TheUmovprinciplestatesthat fundamental parameterswhicharenoteasilymeasured Fresnel reflectionwithinarandomcloudofopaque for surfacesofsimilarstructurethepolarizationis and observationsofastronomicalobjectswithknown inversely correlatedwithgeometricalbedo.Itis and controlled;theycombinetodeterminethereadily curve iscontrolledbythesurfacestructureandopacity, Experimentally, theformofpolarization-phase polarized componentisproduced byinternalturbidity This isanaturalresultif the polarizedcomponent same amountofpolarizedlight, sothatdifferencesin equivalent tothestatementthatallsurfacesreflect albedo areonlydifferences intheunpolarizedflux. and randomdiffractionfrom veryfinedustparticles. comes frompuresurface reflections whiletheun- a 433 Eros 349 Dembowska 324 Bamberga 887 Alinda 654 Zelinda 511 Davida 141 Lumen 139 Juewa 20 Massalia 40 Harmonia 31 Euphrosyne 23 Thalia 21 Lutetia 42 Isis 39 Laetitia SomedatatakenintheVfilterareincorporatedslope 89 Julia 63 Ausonia 51 Nemausa 15 Eunomia 12 Victoria 11 Parthenope 19 Fortuna 17 Thetis The theoryofWolff(1974),whichmodelsthepolar- 8 Flora © American Astronomical Society • Provided by theNASA Astrophysics Data System Object Vesta Hebe Juno Pallas Iris Ceres Astraea Table V.Asteroidpolarimetricparameters II. THESLOPE-ALBEDOLAW measured inthegreenfilter. Pnün% Ne% 0.75 0.70? 0.75 0.60! 0.70 0.70? 0.65? 0.60? 0.65? 0.70? 1.65! 0.75 1.35 0.70? 0.75 0.85? 0.55: 0.75 0.35 1.30? 1.65 1.80? 1.25? 1.70? 1.25? 1.95 a a 10 10 11 18.1 4 7 5 5 6 0.0521.70.1040.160 4 0.0420.70.3250.051 6 0.0520.9 7 0.0420.9 2 •••20.2?0.317?0.052 Ascending branch 0.02 0.03 0.09 0.02 0.03 0.15 0.04 0.08 19.70.216 0.03 19.80.1000.166 0.13 22?0.082?0.202 0.17 20?0.100?0.166 ••• 20.60.273 04 24.20.1650.101 21.8! 21.1! 20.8 20.1? 0.103?0.161 18.2 18.1! 19.1: 19.5: 19.9? 0.088?0.188 ao MINOR PLANETS.XVI. 0.253! 0.090: 0.065! 0.089: 0.213 0.094! 0.087 0.094 0.099 Slope albedo Green 0.066 0.176 0.254 0.186 0.078 0.190 0.183 0.168 0.177 0.061 0.077 parently exist,systematicdifferencesinitsnumerical was firstnotedbyWidorn(1967)andindependently where aisthegeometricalbedoofdiffuselyreflecting Zellner (1974),andmostrecentlybyHowelletal. by KenKnightetal.(1967).Theconstantshavebeen surface andhisthepolarimetricslopedefinedabove, form formeasurementsmadeatvariousopticalwave- of diffusereflection.Whilegenuinedeviationsap- established byVeverkaandNoland(1973),Howell Zellner andCapen(1974)isused;(3)revised ultraviolet isomittedduetoitspoorlyknownalbedo; lengths orforsamplesofdifferentopacity,mineralogy, tory data.Thelawseemstobeaverygeneralproperty 1620 Geographos polarization datafromunpublishedobservationsatthe by Howelletal.(1973)inthat(1)Mercurythe reexamined inTableIX.Thedatadifferfromthoseused detected. composition, origin,orsurfacestructurehavenotbeen new parametersforsolar-systemobjects.Themean polarization slopescharacteristicofthelightestand University ofArizona. ofEuropaandGanymede,fromMorrison strict formoftheUmovlaw,dP/P=—àa/a.The'last derived valueforc\isunity,inaccordancewiththe have absolutemagnitudesknowntobetterprecision. two columnsofTableXgivetheexpectedalbedos,using Cruikshank (1974),areusedalongwithimproved darkest asteroidsyetobserved.Thescatterisno the fourindependentsetsofcalibrationdata,for greater than±3%intheimpliedradius.Fewasteroids (1973), fromalargebodyofastronomicalandlabora- greater than±6%ofthederivedalbedo,i.e.,no (2) forDeimosthenewphotometryandpolarimetryby 532 Herculina0.80 29 Amphitrite0.75? 89 Julia 20 Massalia An empiricallawoftheformloga=—cilog/z+C2, The slope-albedolawforsolar-systembodiesis 15 Eunomia Table VII.Asteroidpolarimetricparametersfromthedata Table XisadaptedfromHowelletal.butwiththe 4 Vesta0.55 9 Metis 8 Flora Object Pmin% Object Pmin%Ne%otoSlopeAlbedo Table VI.Asteroidpolarimetricparameters by J.Veverka(1970),takeninwhitelight. 0.9: 0.80 0.50 0.65 0.65 0.6 measured intheVfilter. 8 0.1322.1:0.119:0.140 N e%«oSlopeAlbedo 4 0.2518?0.074?0.224 Ascending branch Ascending branch 0.10 0.01 0.06 0.09 20.8 20.3 21.9 18.8 0.120 0.115 0.062 0.093 0.178 0.144 0.138 0.268 1105 1974AJ 7 9.1100Z were providedbyC.R.Chapman fromhisnarrow-bandspectrophotometry. observations, attheUniversityof Arizona. ParenthesesindicateobjectsnotobservedontheUBVsystem; approximate£—Vcolors Asteroid 1106 a Sourcesincludethecompilations byGehrels(1970)andTaylor(1971),theworkofVeverka(1970), andpublishedunpublished No. 21 20 23 22 10 97 93 44 43 42 40 39 37 32 27 25 89 88 85 84 82 62 60 52 51 30 15 68 61 53 14 63 29 19 18 13 12 11 79 16 17 © American Astronomical Society • Provided by theNASA Astrophysics Data System 9 3 4 2 8 6 5 7 1 (0.68:) (0.72:) (0.64) (0.83) (0.69) (0.72) (0.68) (0.80) (0.84) (0.77:) (0.96) (0.90) (0.90) (0.84) (0.89) (0.95) B—V €b~vU—B£(1,0)F(1,0) 0.80 0.70 0.85 0.83 0.76 0.65 0.69 0.81 0.81 0.81 0.87 0.82 0.80 0.72 0.70 0.80 0.92 0.87 0.81 0.83 0.83 0.83 0.76 0.85 0.67 0.88 0.88 0.86 0.69 0.82 0.89 0.84: 0.01 0.02 0.01 0.01 0.03 0.07 0.05 0.06 0.02 0.04 0.00 0.03 0.02 0.03 0.01 0.02 0.00 0.02 0.02 0.01 0.06 0.04 0.03 0.02 0.01 0.01 0.08 0.46 0.39 0.26 0.40 0.36 0.42 0.43 0.50 0.40 0.42 0.43 0.22 0.35 0.38 0.45 0.45 0.44 0.24 0.41 0.42 0.49 0.45 0.43 0.42 0.38 0.28 0.51 ZELLNER, GEHRELS,ANDGRADIE a Table VIII.Adoptedasteroidmagnitudesandcolors. 10.27 10.05 4.31 8.67 8.75 8.68 6.43 8.22 8.91 6.57 5.18 4.11 7.84: 9.42 9.28 8.29 9.83: 8.00 8.20 8.77 9.81 9.18 8.02 8.84 8.49 8.74 8.35 6.29 8.81 7.30 6.84 8.66 8.78 9.07 7.79 8.69 6.89 7.41 7.97 7.63: 8.45 7.41 8.56 8.34 7.48 7.78 7.54 6.70 7.26: 7.48 9.47 6.19 3.55 8.00: 4.53 8.06 5.87 5.64 8.53 9.07 3.42 7.95 7.0: 9.04: 7.54 8.38 9.19 7.45 7.92 6.97 6.60 6.45 7.25 6.94: 8.22 6.53 6.67 6.67 8.15 7.63: 7.86 5.48 6.98 6.03 7.86 6.42: 6.76 7.33 7.98 5.87 7.63 7.60 7.90 7.90 7.47 7.35 7.66 7.17 Asteroid 1685 1620 1566 1362 1437 1291 1287 1043 1212 1036 No.' 976 911 887 337 335 324 658 654 341 321 268 230 747 739 704 584 409 356 349 326 200 624 563 554 540 498 402 380 354 510 532 511 471 433 196 192 181 141 140 130 122 115 110 108 (0.67:) (0.70) (0.90) (0.82) (0.66) (0.73) (0.92) (0.70:) (0.75) (0.76) (0.72) (0.84) (0.87) (0.80) (0.72) (0.77) (0.82) (0.84) (0.64) (0.69) (0.94) 0.82 0.87 0.80 0.72 0.72 0.83 0.85 0.69 0.90 0.74 0.80 0.89 0.87 0.96 0.92 0.69 0.81 0.90 0.73 0.72 0.93 B-V 0.78 0.84 0.70 0.77 0.68 0.71 0.88 0.02 0.00 0.02 0.06 CB-V U-B£(1,0)V(1,0) 0.36 0.50 0.39 0.36 0.66 0.20 0.45 0.23 0.25 0.36 0.36 0.55 0.24 0.44 0.29 0.25 0.48 0.54 0.41 0.30 0.44 0.36 0.36 0.46 12.3 14.6: 11.46 12.13 16.67 17.55 11.02 10.10: 10.05 10.00 10.86 11.72 10.05 10.55 12.64 10.13 11.38 15.4 11.04 10.61 12.22 12.40 9.23 8.0 8.14 8.40: 8.92 9.88 9.11 9.55 8.61: 9.65 9.08 9.57 9.05 9.12: 8.80 7.60: 8.67 9.49 8.63 9.99 7.29 9.44 7.68 7.95: 9.99 9.31 8.83' 7.98: 7.13: 7.56 7.86 9.47: 11.6 10.63 11.28 13.8: 16.75 10.12 15.80 10.57 11.72 10.85 14.5 11.32 10.31 11.52 8.51 7.3 6.76 9.81 9.43: 9.23 8.40 9.15 9.34 7.18: 8.30: 8.09 9.89 9.41 7.41 8.86 7.77: 8.75 8.25 8.12 8.87: 9.15 6.33 7.53: 8.37 6.90: 8.74 9.22 7.91 8.35 6.63 7.14: 6.43: 7.89 1974AJ 7 9.1100Z With F=—26.77andB—V+0.63fortheSunfrom the followingequations: our polarimetricgreenfilter. where BandVarethestandardfiltersGindicates Gehrels etal.(1964),asteroidradiiarecomputedfrom kept inmind,however.First,thelawisanaverage method, thepolarimetrictechniqueisfreeofmodeling of asteroidalbedosandradii.Unliketheradiometric bodies ofuniformalbedo.Severallimitationsshouldbe independently ofanyphotometrytheobjectin fails forEarth-basedobservationsoftheTrojansand below 5%;thepossibilityremainsthatlawcould deviate substantially.Also,fewgoodlaboratorymea- relationship fromwhichindividualobjectsmight question, andisnotmisledbyrotationfornonspherical assumptions. Itgivesthegeometricalbedodirectly, reach, atleastpérihélieapparitions,butthemethod angle, whichrangesfrom18°to24°forasteroids can beobservedatphaseanglesbeyondtheinversion saturate orbecomedegenerateforverydarksurfaces. surements havebeenmadeformaterialswithalbedos satellites oftheouterplanets. Finally, themethodisapplicableonlytoobjectsthat small andirregularvariationswithwavelength,while wavelength dependenciesareoppositeinsignandtend however, evenatphaseanglessmallerthan5°;thetwo in TableXLPresumablytheintrinsicnegative-branch generally smalleratlongerwavelengths.Theslope microscopically intricateor particulatesurfacesof well-developed negativebranch isobserved.The is darkest.Thepositive-polarizationeffectfelt, and therigorwithwhichitholdsmaybejudgedby especially fortheredderasteroidsslopesare and inthetablesthatparameterPishowsonly negative branchisknownexperimentally toresultfrom agreement ofdiameterscomputedattwowavelengths effect isclearlyaconsequenceoftheUmovprinciple, to cancelnear10°phaseatvisiblewavelengths. effect isalsostrongestatwavelengthswherethesurface has beenexplainedbyWolff(1974) asaneffectofdouble internally acrossacharacteristic scatteringlength,and sufficient opacitysothat little lightistransmitted and aareplottedinFigs.34.Forallobjects (Fig. 4).Mostofthemain-beltasteroidsarewithin mn 0 III. SURFACESTRUCTURE,ALBEDO,ANDCOMPOSITION We adoptfortheasteroids Thus, wehaveausefultoolforremotedetermination Wavelength dependencies:ItmaybenotedinFig.1 Surface structure:FrequencydistributionsofPin m © American Astronomical Society • Provided by theNASA Astrophysics Data System 2 logf=5.894—0.45(1,0)—log##, 2 logr=5.642-0.47(1,0)-loga, 2 logr=5.718-0.4^(1,0)+0.28(^-7)-loga, F G Ioga= —log&—1.78. MINOR PLANETS.XVI. byC.R.Chapman(personalcommunication). have beenfoundforcertainfine-grainedlunarbreccias Negative polarizationsoverlappingtheasteroidrange reflection inarandomcloudofopaquecrystalsurfaces. objects, B—Vcolorsweresynthesizedfromnarrow-bandspectro- polarimetric grounds,thatunconsolidatedsurface Thus wesuspect,butcannotprovecategoricallyon never beenfoundfordust-freelaboratorysamples. but arenotcharacteristicofwell-consolidatedsurfaces. surfaces suchaschipsofcoal(Zellnerunpublished), polarimetric diametersareofteningoodagreementwith Pmin greaterthan1.4%,asseenformanyasteroids,has last columnofTablesIV-VIIandthemagnitudesin regoliths arecharacteristicoftheasteroidpopulation. is furtherexaminedbyChapmanetal.(1975);ita results fromtheradiometricmethod(Matson1971; regions aregenerallyingoodagreement.Thelasttwo Table VIII.Resultsfromdataindifferentspectral diameters derivedfromthepolarimetricalbedosin Europa G Deimos B Mercury B U albedos derivedfromtheadopteddiameters.The columns ofTableXIgivevisual-wavelengthgeometric serious oneandislikelytoberesolvedonlybythe ever forsomeobjects,notably(324)Bambergaand Ganymede G are notconfirmedbythepolarimetry.Thisdiscrepancy Cruikshank andMorrison1973;1974).How- (Bowell etal.1972)andforsomehighly-opaqueclean (511) Davida,theextremelylowradiometricalbedos Object FilteraSlopehlog Fig. 2.ThedistributionofasteroidB~Vcolors.Formany Albedos andDiameters:TableXIlistsasteroid Table IX.Theslope-albedolawforsolar-systembodies. B V V 0.120 0.148 0.095 0.175 0.44 0.031 0.68 0.020 0.064 0.263 0.104 0.147 0.072 0.230 0.085 0.172 -0.921 -0.830 -0.357 -1.509 -0.983 -0.833 -1.022 -0.757 -1.143 -0.638 -1.195 -0.580 -0.167 -1.699 -1.071 -0.764 1107 1974AJ 7 9.1100Z , known slope-albedolaw,orbyathird,independent means ofasteroiddiametermeasurement. laboratory identificationofmaterialsthatviolatethe measured byBarnardandothers(seeDollfus1971). 1108 not bydiffractionfora1-mtelescope.Webelievethat limit of0.5arcsecsetbyatmosphericturbulenceand are systematicallyabout1|timeslargerthanthose for thepoorlydefinedlimbsofasteroidsBarnardwas topic. Inapparentsizetheasteroidsarecloseto Following Dollfuspaperthereisalivelydebateonthis led toplacehismicrometerwirestooclosetogether, an errorthatwouldnotoccurforthedouble-starwork idence fortheexistenceoftwodistinctasteroidcomposi- radiometric, polarimetric,andspectrophotometricev- at whichhewashighlyskilled. meteoritic types.Thedichotomycanbeseeninthe of carbonaceouschondritesandthemorerefinedsilicate tional classes,tentativelyidentifiedastheanalogues Our diametersandthosefromtheradiometricmethod Compositional classes:Chapmanetal.(1975)present 37 Telescopically-observed139 35 Lunarrocksandfines135 72 Terrestrialsamples81 © American Astronomical Society • Provided by theNASA Astrophysics Data System 5 Solar-systembodies8 1685 Toro 1620 Geographos 1566 Icarus 433 Eros 324 Bamberga 887 Alinda 654 Zelinda 532 Herculina 511 Davida 141 Lumen 40 Harmonia 39 Laetitia 23 Thalia 21 Lutetia 20 Massaha 89 Julia 63 Ausonia 19 Fortuna 17 Thetis 15 Eunomia 11 Parthenope 4 Vesta 9 Metis 8 Flora 1 Ceres lunar regions Object Material Table X.Theslope-albedolawloga=—ci\0gh-\-c2forfourindependentsetsofcalibrationdata. Number ofslopes (all wavelengths) ZELLNER, GEHRELS,ANDGRADIE 1043! 478! 220! 553 262 188! 181 109: 156 109! 142 104! 130 150? 150 180! 120 Blue Table XI.Asteroidpolarimetricalbedosanddiameters. 91 90 90 88! 82 15.8: 4.1 6.0? 2.1? 1.4? 0.04^0.25 0.07-0.68 0.917 0.03-1.00 0.05-0.50 S traightaverage1.00 Albedo limits 1058! 225! Green 587 504! 245 198 192! Ill: 151 102? 104 165 110 138? 188? 94 94 78 15.6? 1.3? Diameter km ±0.06 phasize thatthewide-bandphotopolarimetricproperties vary greatlyfromasteroidtoasteroid,thegeneral bimodalities ofFigs.2,3,and5,isheredemon- decreasing mineralopacity,i.e.,increasingtransmission details ofsurfacestructuresuchasparticlesizedonot colors only,inFigs.6and7.Ifwemayassumethat strated, forpolarimetricparametersandB—V through individualgrains.However,weshouldem- trend upwardtotherightinbothdiagramsrepresents polarimetric albedointherange0.14-0.21isnoted. are sensitiveonlytobroadlydefinedopacityclasses reddish B—Vnear+0.85,shallowPi0.7,and and nottodetailedmineralogicalorpetrologicaltypes. many moderate-opacitysilicatesinpowderedform(e.g., Hapke 1971;Dollfusetal.1971),andsomeofthese man andSalisbury1973).Asecondopacityclass, Such colorsandpolarizationsarecharacteristicof to thoseofspecificsilicaceousmeteoritictypes(Chap- asteroids areknowntohavereflectionspectrasimilar mn 0.99 1.03 1.05 490 279 A markedclusteringofatleast16objectswith C\ 156 156 Least squares 137 Other 1 9? -1.74 -1.729 -1.80 -1.66 -1.79 Ci Adopted 1050 — 490 222 570 — 279 110 253 - 190 157 156 190 104 - 156 - 137: 109 146 133 150? - 120 182 - 95 90 90 ~ 92 80 - 15.7: 4.1 6.0? 2.0? 1.4? ±0.02 -1.809 -1.760 -1.756 -1.78 -1.780 c% Ci= 1assumed ±0.014 Polarimetric albedo 0.084 0.197 0.200 0.102 0.213 0.187 0.155 0.278 0.068 0.201 0.069 0.145 0.188 0.218 0.196 0.155 0.116 0.073 0.148 0.186 0.184 0.165 0.175 0.058 0.057 0.179 0.058 0.170 0.147 0.210 0.267 0.258 0.239 0.270 0.255 av —logav 0.065 ö,Ä=0.30 ±0.003 0.052 0.058 0.058 0.056 0.055 0.70 0.99 0.73 0.81 0.72 0.66 0.71 0.56 0.73 0.67 0.81 0.84 0.93 0.76 0.83 0.74 0.70 0.70 0.75 0.78 0.77 0.68 1.08 1.17 0.83 1.13 1.16 1.23 1.24 1.24 1974AJ 7 9.1100Z Fig. 3.ThefrequencydistributionofthedepthPi scopically (JohnsonandFanale1973).Pigreater 511) isseenwithP—Fnear+0.7,i1.6%, comprising atleastsixobjects(1,2,19,141,324,and silicates andhasbeenreliablydemonstratedonlyfor than about1.6%isoutsidethemeasuredrangefor to resemblecertaincarbonaceouschondritesspectro- and albedosbelow0.09,includesobjectsreported Dembowska indicateseitherawell-consolidatedsurface dust andcandlesoot. or elseanexceptionallytranslucentregolithmaterial. Cl chondritesandcarbonaceoussubstancessuchascoal Nemausa, (63)Ausonia,and(21)Lutetiabecauseof Also inclassesbythemselvesare(4)Vesta,(51) otherwise unremarkableintheiropticalproperties. its largeinversionangle.Wenotethatallfivesmall objects inMars-crossingorbits(433,887,1566,1620, mn and 1685)fallinthelower-opacitygroupbutare mn mn The shallownegativebranchobservedfor(349) Deimos andthedarkersideoflapetusaresimilarto Fig. 4.Thefrequency distributionoftheinversion anglea 0 © American Astronomical Society • Provided by theNASA Astrophysics Data System negative branchforasteroidsandotherobjects. for asteroidsand otherobjects. MINOR PLANETS.XVI. lighter ones,butnoasteroidsexhibitthereddishcolor less effectivefortheasteroids.Thismayresultfrom on thelunarsurface(e.g.,Hapke1973)areapparently Mercury. Darkeningmechanismsbelievedtooperate the darkerasteroidsinFigs.6and7,Callistoto the reducedsolarparticleandphotonfluxin and relativelylowpolarimetricalbedooftheMoon ,or,aspointedoutbyChapmanand from subsurfacematerialwitharelativelyshorttime that asteroidregolithsarelosttospaceandreplenished Salisbury (1973),itmaybeaconsequenceofthefact scale. Fig. 5.Thefrequencydistributionofpolarimetric albedos forasteroids. 1109 1974AJ 7 9.1100Z 1110 particularly for433Eros,weexpecttoidentifyrotation well-observed objectsincreasedtoperhaps50,after will besubstantiallyimproved,andthenumberof Wolff theoryshouldpermitdirectcomputationof least forafewofthebrighterobjects.Insomecases, range fromtheultravioletintonearinfraredat photometric aswellpolarimetricquantitiesinterms laboratory andtheoreticalworkisalsoneeded.The from themoresophisticatedtechniques.Support another ’swork.Wehopetoextendthewavelength and aspecteffectsinthepolarization. polarimetry ofsuper-darkmaterialsallkinds,since nomical work,hasyettobeapproachedinthelabora- investigate deviationsfromtheslope-albedolaw,or surements havebeenmadewithsufficientprecisionto of fundamentalopticalproperties.Fewlaboratorymea- etry ofasteroidsisneededforinterpretationresults such asPmin.anda)polarimetryfreeofsystematic niques suchasradarbackscattering andinterferometric to delineatewavelengthdependenciesinparameters tory. Weespeciallyfeeltheneedforprecisionlaboratory errors atthe±0.01%level,acommonplaceinastro- diameter measurementswill prove invaluable. asteroid albedosmayrangeaslow2%.Newtech- Minor PlanetCenter,forfurnishing accurateephem- 0 The precisionofpolarimetricparameterslistedhere A majornewprogramofhigh-qualityUBVphotom- We areindebtedtoDr.Paul Herget,Directorofthe © American Astronomical Society • Provided by theNASA Astrophysics Data System Fig. 7.PolarimetriealbedovsB—Vcolorfor asteroids andotherobjects. ACKNOWLEDGMENTS IV. FUTUREWORK ZELLNER, GEHRELS,ANDGRADIE B-V Bowell, E.,Dollfus,A.,Zellner,B.,andGeake,J.E.(1973). Bowell, E.,Dollfus,A.,andGeake,J.E.(1972).InProceedings Aeronautics andSpaceAdministration. telescope time.Someoftheobservationsweremadeby Planetary Laboratoryforgenerousallotmentsof Bowell, E.,andZellner,B.H.(1974).InPlanets,Stars, and others.ThisworkissupportedbytheNational G. V.Coyne,L.Dunlap,M.Howes,K.Serkowski Kea, andStewardObservatoriesoftheLunar erides andtotheDirectorsofMcDonald,Mauna Chapman, C.R.,McCord,T.B.,andJohnson,V.(1973). Dollfus, A.(1961).InPlanetsandSatellites,editedbyG.P. Chapman, C.R.,Morrison,D.,andZellner,B.H.(1975). Chapman, C.R.,andSalisbury,J.W.(1973).Icarus19,507. Cruikshank, D.P.,andMorrison,(1973).Icarus20,477. Dollfus, A.(1971).InPhysicalStudiesofMinorPlanets,edited Dunlap, J.L.(1974).Astron.79,324. Dollfus, A.,Bowell,E.,andTitulaer,C.(1971).Astron. Dunlap, J.L.,Gehrels,T.,andHowes,M.L.(1973).Astron. Gehrels, T.,andTeska,T.M.(1960).Publ.Astron.Soc.Pac. Gehrels, T.(1970).InSurfacesandInteriorsofPlanets Hapke, B.(1973).TheMoon7,342. Hapke, B.(1971).InPhysicalStudiesofMinorPlanets,edited Gehrels, T.,Coffeen,andOwings,D.(1964).Astron.J.69, Lyot, B.(1934).C.R.Acad.Sei.Paris199,774. Jones, T.J.,andMorrison,D.(1974).Astron.J.Tobepublished. 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