19 67 Ap J. . .147. .743S a physicalconnectionbetweenthetwo. concentration varieswithtimeandlocationontheplanet.TypicalamountsofH0areorder The presenceofH0intheatmosphereMarsappearstobeconfirmed,butindicationsarethatits the 1964-1965apparitionhavebeenexaminedforDoppler-shiftedrotationallinesofH0nearX8200. amount ofwaterinthevaporphaseseemstodependuponsizeMartianpolarcap,implying ments ofRank,Fink,Foltz,andWiggins(1964)theyderivedanH0abundance14± 10-20 uprécipitablewatervapor. Jungfraujoch, derivedaMartianH0abundanceofabout200-/1précipitablewater.The Martian H0lines.Fromtheequivalentwidthsofthesefeaturesandlaboratorymeasure- Mars obtainedatMountWilson.TheyattributedthesefeaturestoDoppler-shifted detected weakabsorptionfeaturesnearX8200Âonahigh-dispersionspectrogramof by anorderofmagnitude,clearlyindicatedtheneed foradditionalobservations. Mount Wilsonworkmustbeconsideredanexploratoryeffort. negative uptothattime.Thesituationasitstoodin1963iswellsummarizedKMS. been madebeforetheKMSinvestigation,spectroscopicresultshaduniformly estimate oftheMartiansurfacepressure.TheC0 studiesarereportedelsewhereby weak A8700bandofC0forbettervaluesabundance and,consequently,abetter sive observingprogramforthe1964-1965apparition. Wealsoplannedtoinvestigatethe We willonlysayherethat,becauseofthelackpositiveresultsinpreviousattempts, For positivedetectionandmorereliableabundance estimates,alargenumberofgood Spinrad, Schorn,Moore,Giver,andSmith(1966; hereinafter referredtoas“PaperI”)* the studyofbiological,geological,andmeteorological problemsledustoplananexten- appearance oftwoindependentpositivedetections ofwatervapor,inamountsdiffering the 1.4juH0bandinspectraofMars,Moon,andstarsasobservedfrom 7 /xofprécipitablewater.AlthoughvariousindirectestimatestheamountH0had 2 2 2 2 2 2 2 2 2 2 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem The spectroscopicresultsarecomparedwithphotographicpatrolstudiesduringthisapparition Nineteen high-dispersionspectrogramsofMarstakenatMcDonaldandLickObservatoriesduring At thesametimeDollfus(1963),byaphotometriccomparisonofintensities In 1963Kaplan,Münch,andSpinrad(1964;hereinafterreferredtoas“KMS”) The importanceoftheamountwatervapor,if any, intheatmosphereofMarsto HIGH-DISPERSION SPECTROSCOPICOBSERVATIONSOFMARS Space SciencesDivision,JetPropulsionLaboratory,CaliforniaInstitute Berkeley AstronomyDepartment,UniversityofCalifornia Berkeley AstronomyDepartment,UniversityofCalifornia II. THEWATER-VAPORVARIATIONS The RANDCorporation,SantaMonica,California Received May31,1966;revisedAugust8,1966 McDonald Observatory,UniversityofTexas of Technology,Pasadena,California Lawrence P.Giver Ronald A.Schorn Roger C.Moore Harlan J.Smith I. INTRODUCTION Hyron Spinrad ABSTRACT 743 19 67 Ap J. . .147. .743S spectra wereneeded.DetectionofthefaintMartianH2Olinesnearbothquadratures, when theDopplershiftswouldhaveoppositesigns,greatlyreducepossibility with timeandpositionontheplanet.TheobservedbehaviorofMartianpolecaps, serve MarsoveraslongaperiodoftimepossibletoseeiftheH2Oabundancevaried 744 wave ofdarkening,andwhiteclouds,combinedwiththesmallamountH2Obelieved greatly. TheMartianH2OlinesobservedbyKMSwereslightlystrongernearthesouth that weakterrestriallineswouldconfusethepicture.Furthermore,wewantedtoob- humidity. pole thanthenorth,whichalsosuggestedthatwemightbeabletodetectvariationsin made atMcDonald.Althoughthe120-inchcoudéspectrographissomewhatsuperiorto to existintheatmosphereofMars,naturallysuggeststhatlocalhumiditymightvary Because ofthegreaterdemandsonLicktelescope,mostobservationswere months aroundopposition,whentheDopplershiftofMarswastoosmallforourpur- effective forthedetectionofMartianH2Olines. the 82-inchcoudéspectrographinscaleandspeed,experienceshowedthatsubstan- telescopes werecapableofcarryingoutourobservingprogram.TheLickObservatory ment used—“L”fortheLick120-inchtelescopeand“M”McDonald82-inch poses. inch. BythetimeobservingconditionsatLickbecameuncertain,duetousualpoor ready untilDecember.Observationsbeforethattimewereperforcemadewiththe120- tially lowerterrestrialhumidityatMcDonaldmadethesetwoinstrumentsaboutequally spectra arelisted.Thefirstcolumngivesthedate,andsecondindicatesinstru- insured fairlygoodcoveragethroughthewholeapparitionexcept,ofcourse,forafew winter weatherthere,theMcDonaldcoudéwasavailable.Useofboththeseinstruments a grantfromtheNASAOfficeofSpaceSciences,andcoudéspectrographwasnot 120-inch andtheMcDonaldObservatory82-inchtelescopeswereinstrumentsused. corresponds tothebeginningofspringinnorthernhemisphereMars;L=90° shifts inangstromunitsofthesuspectedMartianlinesasmeasuredbySpinrad(AXjy) the beginningofsummer,etc.ThefourthandfifthcolumnsgiveaverageDoppler telescope. Thethirdcolumngivestheplanetocentriclongitudeofsun,L.=0 predictable. Anumberofunderexposed,overexposed, and/ormottledplateswere gives commentsregardingthevisibilityofsuspected H0linesoverthediskofMars. Doppler shiftofMarsderivedfromthetablesNiehausandPetrie(1961).Theseventh a plussignmeansthatitisreceding.Thenumberoflinesusedindeterminingeachaver- and Schorn(AXä),respectively.AminussignmeansthatMarsisapproachingEarth; produced, whichwereunsuitableforouruse. Furthermore, sinceneitherLicknor in speedofafactor20to50whenapplied IV-Nemulsions,wassomewhatun- Mars H2Ospectrawereobtainedonlywhentheterrestrial humiditywasquitelow.In blame forhalfthewastednights,restbeingdue toavarietyoffactors.Successful uled forthisprogram.Exceptionallycloudyweather atbothLickandMcDonaldwasto To bothmeasurersitappearedinDecember,1964, thatthe“Martian”lineswerevisible column istheestimatedabundanceofprécipitablewaterinmicrons.Thelast age isgiveninparenthesisfollowingtheaverage.ThesixthcolunngivesAX,X8200Â record theX8700CO2band (asdescribedinKMS)atthesametimeas X8200H2O layers ofthincloudwere uncertain.Onemoredifficultycanbelaidtoour attemptto McDonald possessedan infrared exposuremeter,exposuresmadethrough thecommon addition, thehypersensitizingroutineused,described inPaperI,whileproducingagain only inthenorthernhemisphereofMars. 8 a 2 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Since thelargestpossibledispersionandimagescalewererequired,onlyafewexisting The 82-inchtelescopeunderwentasubstantialmodificationin1964,madepossibleby The observationsreportedherearesummarizedinTable1.Nineteenwell-exposed We shouldpointoutthatthesespectrarepresent only one-thirdofthenightssched- SCHORN, SPINRAD,MOORE,SMITH,ANDGIVER II. THEOBSERVATIONS Vol. 147 19 67 Ap J. . .147. .743S No. 2,1967SPECTROSCOPICOBSERVATIONSOFMARS745 it wasdifficultsimultaneouslytoexposebothbandsproperly. band. ThesensitivityoftheIV-Nemulsionsusedvariedsomuchoverthisregionthat spectrograms wereobtainedwiththe160-inch-focal-lengthcameraof120-inch jected slitwidthwasabout15pandthepositioned,withaidofanimage telescope coudé-focusspectrograph,atadispersionof4.09Â/mmX8200Â.Thepro- camera ofthe82-inch-telescopecoudé-focusspectrographatadispersion4.14Â/mm at X8200Â.AnimagerotatorwasnotavailableMcDonaldbutallexposuresmade rotator, sothatitpassedthroughthenorthandsouthpolesofMars.Typicalexposure times were2hours.TheMcDonaldplatesmadewiththe160-inch-focal-length 10/24/64 11/17/64 12/27/64. 12/26/64 12/24/64. 12/29/64 12/28/64 12/31/64: January, 1965,weremadewithaprojectedslitof 24 pandrequiredexposuretimesof4 hours. SucceedingMcDonaldspectraweretakenwith aprojectedslitwidthof18pand were alignedroughlynorth-southacrossthecentralmeridianofMars.Platesthrough exposure timesof6hours. vapor contentwaswellbelowthatindicatedinBabcock andMoore,whilesomeofthe scope duringmostoftheexposureslistedinTable 1 wasquitelow.Inallcasesthewater- Babcock andMoore(1947).Thewatercontentof Earthsatmosphereabovethetele- Jungfraujoch solarspectrum.Ingeneral,terrestrial H0lineslistedasintensity—1by Babcock andMoorewereinvisibleonourplates. water vaporpresentatthe timeoftheirobservations.Fromtherelativestrengths ofthe McDonald platesshowedwaterlinesasweakatthose inDelbouilleandRoland’s(1963) Martian atmosphere.However, themeasurementofintrinsicstrengths oftheH0 Martian andtelluriclines theyhadintendedtoestimatetheamountof water inthe 2 2 9/25/64. 9/24/64 5/14/65 5/18/65 5/24/65 1/15/65 1/16/65 6/10/65 1/24/65 1/23/65 1/19/65 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem All exposuresweremadewithammonia-hypersensitizedIV-Nemulsions.TheLick The plateslistedinTable1showFraunhoferlines ofintensity—laslistedby KMS usedU.S.WeatherBureauradiosondedata toestimatetheamountoftelluric Date Obs L L L L L M M L M M M M M M M M M M M 110 114 122 112 20 48 47 31 49 49 49 57 50 57 60 59 61 5° 6 - 377(5) - 468(4) -0 348(4) - 431(4) - 439(7) - .455(2) +0 334(4) + 307(3) - .327(1) - 377(1) AXfl(Â) Recent H0Observations 2 -0 428(6) - 431(5) - 431(4) - .438(3) - 426(5) - 368(5) + 391(4) + 340(7) - 409(4) - 517(3) +0 335(5) + 331(7) - 381(2) - 410(6) - 397(4) TABLE 1 AXß(Ä) AXcf (Â) -0 296 - 413 - 368 - 298 - .438 - 437 - .437 - 403 - 434 - 436 - .436 + 358 - 406 +0 359 + 363 + 361 - 379 - 394 - .376 ^15 ^15 ^15 ^15 ^45 ^15 ~15 ~15 ^15 ^10 ^15^ ^15 ~10 ~10 <15j <15 <151 <15) w*(n) 25 No Martianlinesvisible Probably bothhemi- Perhaps moreinS. N. hemisphereonly Probably bothhemi- In S.hemisphere;less hemisphere spheres spheres over restofmeridian Remarks 19 67 Ap J. . .147. .743S íí,, much moreaccuratedeterminationoftheMartianH2Oabundance. miles fromthenearestradiosondestations(Midland-OdessaandElPaso)itisnotpos- lines inthelaboratorybyRanketal(1964)enabledKMS,theirfinalpaper,tomakea 746 SCHORN,SPINRAD,MOORE,SMITH,ANDGIVERVol.147 sible tousedatafromthosestationsdecideifanightwouldbefavorableforourwork. In practice,wetookaspectrumeveryclearnightandthenexaminedit. being successful. entirely clearofneighboringtelluricH0lines,wasprobablyausableplate. dense cumulonimbuscloudswhichformedeveryafternoonpreventedtheattemptfrom of July14,1965,weattemptedtoobtainadditionalspectraatMcDonald.However, (equivalent widthabout6-9mÂ),andonwhichtheterrestrialX8227H0linewas 2 listed inTable2accordingtotheirlaboratorywavelengthX.Thesecondandfifth 2 ponents moreoften,asonewouldexpect.About two-thirds oftheMartianlinesmeas- only oneoftheplates.Ingeneral,stronger terrestrial lineshad“Martian”com- plates, “b”indicatinglinesvisibleontwotofive and“c”thosevisibleonnoneor Babcock andMoore(1947).Thethirdsixthcolumnslistthefrequencywithwhich columns ofTable2list/bm,theintensitiestelluriccomponentsaccordingto led totheX8300Âregion’sbeingatjunctionof twoplates.Asaresult,“endeffects” ured werecommontobothmeasurers,thesebeing almostentirelylinesinourfrequency each lineshowedaMrtiancomponent,“a”denotinglinesvisibleonmorethanfive ured threetimesbyeach measurerandtheresultsaveraged.Wefoundthat accurately often reducedthevisibilityoflinesbeyondX8274. use severalpiecesofemulsionforeachexposure,combined withourdesiretorecordthe class “a.”Wewishtopointoutthat,duethepresence ofadditionaltelluriclines,some columns ofTable1.Each terrestriallineandsuspectedMartiancomponent wasmeas- X7600 bandof0alongwiththeX8200H 0 andtheX8700bandofC0often water lineswereusedonlyforpositiveornegativeDoppler shifts.Inaddition,theneedto bisecting thestrongterrestrial H0lineswasquitedifficult.Furtherthe microscope 0 2 2 2 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Because McDonald,wheremostofourusefulspectraweretaken,isseveralhundred A usefulruleofthumbwasthatanyplatewhichshowedtheX8700CO2linesclearly During anobservingrunof10dayscenteredaroundtheMarinerIVfly-byMars The terrestrialH0lineswhichweinspectedforpossibleMartiancomponentsare The measurementsofSpinradandSchornaresummarized inthefourthandfifth 2 8141 936 8161 434* 8158 019.. 8169 995. 8164 54f 8162 35t. 8186 371* 8176 975 8193 113 8189 272 8181 848. * Usedonlyfornegativeshifts, t ProbablyXo827423(—1Feilab),notMarsH2O. t Usedonlyforpositiveshifts Xo(Â) Telluric H0LinesInspectedforMartianComponents 2 /bm III. WAVELENGTHMEASUREMENTS (20) (20) (20) (20) 10 9 9 9 9 9 8 Visibility TABLE 2 8197.704. 8226 962.. 8218 114* 8243 488f 8256 515.. 8274 354J 8272 042* 8282 024. 8279 600 8287 940 Xo(A) Ibm (20) (20) (20) (20) 10 12 12 9 9 8 Visibility 19 67 Ap J. . .147. .743S 1 No. 2,1967 positions ofthecenterandlimbMarson the characteristiccurveofIV-N from NiehausandPetrie(1961)afterthemeasurementsweremade. probable errorshere.Weestimatethatoursystematicmeasuringcouldeasilybe some detail,soweshallbebriefhere.Itisimpossibleforustosaythataparticular personal biasinthemeasurementsMartianDopplershiftat8200Âwascomputed As isclearfromTable1,thisplaterepresentativeandwasnotchosenforparticularly line, forexample,isvisibleinbothhemispheres.This strengthensourbeliefthatmostof possible CNblendsmentionedinKMSdonotaffect ourresultsappreciably. blend isXo8274.35,andanFeilinehasbeenobservedinthelaboratoryatX8274.35. good agreementbetweenmeasuredandtrueDopplershifts.Infact,justtheoppositeis convincing. Table3givesinmoredetailthemeasuresforMcDonaldcoudéplate4290. respondence ofmeanobservedshiftsandpredictedforeachplatebecomesmore crosshair tendedtoobliteratetheweakMartiancomponents.Forthesereasons,andbe- emulsion, aFraunhoferlineshouldbehavesimilarly nearbothlimbs.TheXo8274.35Fe exactly byFraunhoferlinesofintensity—1seems tousbequitesmall.Inaddition, “Martian” componentisnotafaintFraunhoferlineshiftedoutfromunderthestrong identifications andwavelengthmeasurements.ThisquestionwasdiscussedbyKMSin column givescommentsrecordedatthetimemeasurementsweremade.Toreduce cause ofthesmallnumberlinesinvolved,wefeltthatitwouldbemisleadingtoquote be requiredtoobtainthem. Mars. Whileacenter-to-limbvariationinlinevisibility couldbecausedbythedifferent the faintDoppler-shiftedcomponentswereoften seenoveronlyonehemisphereof Fraunhofer linesofintensity—1inBabcockand Moore(1947),butlinesofintensity Thus wehaveomittedX8274.35fromconsideration.Asageneralruleourplatesshow whether ornotanyMartianH0componentswereseennearothertelluricH2Olines. In everyplatethatwassuitableformeasuringinregionthisFeilinedetected, telluric absorptionline.TheonelinethatdefinitelyisaffectedbyaFraunhofer columns give,respectively,themeasuredAX’sofSpinradandSchorn.The“Remarks” true. ThefirsttwocolumnsarethesameasthoseinTable2,whilethirdandfourth the “Martian”linesarejustthat.Forreasons given,wehaveconcludedthatthe — 1.Thechancethatasizablenumberofthetelluric linesweusedareunderlaidalmost — 2and—3arequiteinvisible.Theintensityofthe “Martian”componentsisroughly ±0.040 Â.Thescatteronindividualmeasuresislargebut,intheaggregate,cor- 0 2 2 1 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Veryhigh-resolutionspectrograms ofJupitercouldresolvethisproblem,butanimage tubewould Observations extending through bothquadraturesenableustogreatlyreduce the It remainstodiscussthepossibilityoffainttelluricorFraunhoferlinesaffectingour Wavelength MeasurementsforMcDonaldPlate4290(December24,1964) True Dopplershift 8256 515 8193 113 8158 019 8197 704 8181 848 8176 975 1889 272. Average Xo(A) SPECTROSCOPIC OBSERVATIONSOFMARS •Tbm (20) (20) (20) (20) (20) 9 9 -0 348 -0 438 AX„(Â) 0 385 0 306 4ÍÓ 290 TABLE 3 -0 335 - 418 - 464 - .460 - 455 -0 434 AX(Â) fi 0 428 Poor line(bothmeasurers) Poor line Poor line Good line(bothmeasurers) Good line(bothmeasurers) Remarks 747 19 67 Ap J. . .147. .743S 1 -1 -1 militates againsttheirbeingtelluriclines. used toderiveW\,theequivalentwidthofMartianH0lines.Fortheseand known recognizeroflinearpatterns,itcanpickoutlineswhicharelostinplate-grain very weakH0lineslieonthelinearpartofcurve ofgrowth,wemaywriteforthe with thoseofnearbyFraunhoferlinescomparableintensity(0or—1).Fromtheatlas generally haspooraccuracycomparedtoitstypicalperformanceinothercases. meter ofprécipitablewater. AccordingtotablespreparedbyKaplan(1966) thiscor- amount ofH0inaverticalcolumn our valuesofW\foreachplatemaybeuncertain byafactorof2.Assumingthatthese plate ofJune10,1965.ThescatterW\valuesforindividuallinesisquitelarge,from2 lines, andthustheequivalentwidthsofweakH0components.Typicalvaluesfor responds toS=1.3cm“ perprécipitablecentimeterat200°K.Thelatter temperature et al.(1964)havepublishedvaluesfortheintensities SoftheH0linesatX8176.97, of DelbouilleandRoland(1963)wedeterminedtheequivalentwidthsFraunhofer other platestheintensitiesofsuspectedMartianlinesalsowerecomparedvisually of thestrongtelluricH0linesforthisLickplate,whichwastakenwithrelativelyhigh prints ofthespectrathemselvesandreproductionstracingsperformpoorlyas noise onamicrodensitometertracing.Figure2showsmicrophotometertracingofthe content oftheatmosphereatthattimewascomparabletoourlaterMarsspectra.Close possibility ofcontaminationbytelluriclines.Theprobabilityfaintlinesoc- and r]istheeffectiveairmassfordoubletraversal oftheMartianatmosphere.Rank illustrations, fortheusefulH0linesarewidelyandirregularlyspaced.Still,Figures1 southern thirdoftheLickplatetakenJune10,1965.Thisisoneourbesttracings,and telluric linesarenotaproblemhere.Ofcourse,thedifferenceinvisibilityofweak examination ofthesesolarspectra,whichareingoodagreementwithBabcockandMoore on ourplates,formosttelluricH0linesofintensity—1areinvisiblespectra.In Solar TelescopeatKittPeakin1963.Thedispersionusedwas0.95Â/mm,andtheH0 addition, oneofus(Schorn)tookseveralsolarspectrathisregionwiththeMcMath we feelthatalineofintensity—2wouldhavenegligibleeffectinproducingconfusion 8226.962, whichhasanearbyunidentifiedlineofintensity—2atXo8227.25.However, where Wistheobservedequivalentwidthofaweak lineincm,Sisthestrength, taken inashorttimeinterval,shouldbeconsiderably moreprecise.Weestimatethat to 15mÂ,buttheaggregateofseverallinesonaplateand,especially,plates terrestrial humidity.Becauseoftheabove-mentionedfactorsourspectrophotometry Figure 2showsthatthesuspectedMartiancomponentsaresuperimposedonwings traces wereusable.^Thelinesareextremelyweak,asFigure1shows.Astheeyeisbest X 8189.27,andXo8226.96. At300°KtheiraverageintensityS=1.0cm percenti- W\ are4-10mÂ.Thehighestvaluewefoundforwasabout15mÂ,theLick and 2areusefulinillustratingsomeofthedifficultiesthisinvestigation.Inparticular, the MartianlineswererelativelystrongoversouthernhemisphereofMars.Both “Martian” H0componentsbetweenthetwohemispheresofMarsatcertaintimesalso quite small.BypickingourlinesaccordingtothesignofDopplershiftwewereable curring atanumberoflocationsonbothsidesourstrongtelluriclinesis (1947) andDelbouilleRoland(1963),increasesourconfidencethatblendswith to avoidalltelluriclineslistedinBabcockandMoore(1947)exceptpossiblyforX 748 2 2 2 2 20 2 2 2 2 0 2 0 © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem Tracings ofplatessuchasthosetakenonDecember24,1964,andJune10,1965,were Most oftheplateslistedinTable1weretracedonamicrodensitometer,butnotall SCHORN, SPINRAD,MOORE,SMITH,ANDGIVER IV. ABUNDANCEESTIMATES 19 67 Ap J. . .147. .743S © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem \ o< O H x~ 0 0< s 0 0 u 1 0 ^ rs r"2^l P No. 2, 1967 SPECTROSCOPIC OBSERVATIONS OF MARS 751 Several blue clearings occurred during this apparition: planet-wide clearings were ob- CDr- served on December 6-10, 1964, April 16, 1965, and July 13, 1965; northern hemisphere oc clearings on September 26-October 7, 1964, December 29, 1964, January 2, 1965, and March 10-15, 1965; evening hemisphere clearing on January 11. These blue clearings produced no spectroscopic effects that we noticed in the region XX7600-8700 Â. VI. CONCLUDING REMARKS The present work indicates that H20 does exist in the atmosphere of Mars and that the amount present varies significantly with time and place on the planet. Furthermore, the mass motion of H20 in the atmosphere of Mars appears to be correlated with polar- cap recession and growth, and possibly with the frequency of appearance of white MARTIAN DATE APRIL MAY JUNE JULY AUGUST 54° 57° 60° O 63° Z) <1 - 69o 0 (-cc 72° 1 75° o £ TS» < 8 Io 84° 87° TERRESTRIAL DATE Fig. 3.—North polar cap regression during the 1964-1965 apparition according to Capen el al. (1966). The solid curve and solid circles are measurements in red-orange light. The dashed-curve crosses are yel- low-green measurements. clouds and intensification of dark features on the surface. All these conclusions rest on a rather weak observational base, however. Clearly these results must be checked thorough- ly during coming apparitions. Although large amounts of observing time are required, using the finest available telescopes and best coudé spectrographs, no instrumental “breakthroughs” are needed. We intend to follow the problem up thoroughly to see if the results of this paper stand up in the light of more and better observational data. In this largely observational program we owe a real debt to Dr. F. J. Quimby and Messrs. Claude Knuckles and Graydon Hicks for helping obtain our spectra, and to Mr. Marlyn Krebs and his staff for speeding completion of the McDonald 82-inch coudé improvements. Mr. Charles Capen has been most generous in his time and efforts to keep photographic and spectrographic studies of Mars on a complementary basis. Schorn acknowledges the support of the Jet Propulsion Laboratory, California Insti- tute of Technology, under contract NASA-100 sponsored by the National Aeronautics and Space Administration. Spinrad wishes to acknowledge the support of the Jet Pro- pulsion Laboratory and ONR grant N(ONR) (G)-00006-66. Moore’s share of the work was sponsored by U.S. Air Force under project RAND, contract AF 49(638)-1700. © American Astronomical Society • Provided by the NASA Astrophysics Data System 19 67 Ap J. . .147. .743S Babcock, H.D.,andMoore,C.1947,TheSolarSpectrum\66000-\13495(CarnegieInstitutionofWash- Adamcik, J.A.1963,PlanetSpaceSei.,11,355. .1965,ibid.,261,1603. .1963,Compt.Rend.,256,3009. Delbouille, L.,andRoland,G.1963,PhotometricAtlasoftheSolarSpectrumfrom\7498to\12016 Kuiper, G.P.1952,TheAtmospheresoftheEarthandPlanets,ed.Kuiper(Chicago:University Dollfus, A.1961,PlanetsandSatellites,Vol.3:TheSolarSystem,ed.G.P.KuiperB.Middlehurst Capen, C.,Young,J.,andV.1966,JPLTech.Kept,(inpress). 752 Leighton, R.B.,andMurray,B.C.1966,Science,153,136. Lebedinskii, A.I.,andSalova,G.I.1962,SovietAstr.—A.J.,6,390. Kaplan, L.D.,Münch,G.,andSpinrad,H.1964,Ap.J.,139,1(“KMS”)- Kaplan, L.D.1966(privatecommunication). Niehaus, W.C.,andPetrie,T.1961,TablesofStellarPlanetaryDopplerShiftsfrom1962to1982 Rank, D.H.,Fink,U.,Foltz,J.V.,andWiggins,T.A.1964,Ap.J.,140,366. Sagan, C.1961,Ap.J.,66,52. Vaucouleurs, G.de.1954,PhysicsofthePlanetMars(London:Faber&Faber),p.219. Spinrad, H.,Schorn,R.A.,Moore,C.,Giver,L.P.,andSmith,H.J.1966,Ap.J.,146,331(PaperI). ington Pub.579[Washington,D.C.:CarnegieInstitutionofWashington]). © American Astronomical Society •Provided bytheNASA Astrophysics DataSystem (Standard OilCo.ofOhio). Chicago Press),p.362. (Chicago: UniversityofChicagoPress),p.381. (Institut d’AstrophysiquedeFUniversitéLiège). SCHORN, SPINRAD,MOORE,SMITH,ANDGIVER REFERENCES
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