1992ApJ...391L..99B THE © surrounding far-infrared, associated emission expected CO in densities disks & lar This Technology Technology the to kinetically these the with mantles ries bined present part Strom, revealed 1992. 2 Observations 3 Little 1 disklike Zuckerman equilbrium-dominated nebula, AsTROPHYSICAL Division Leiden Division chemical gas of emission (see, conjecture larger The putative with on stellar © Edwards, American and is viewed may Subject P suggests submillimeter lar position; extended dance in istry results here toward 10-20 in inferred e.g., that Observatory, line 105-24, 170-25, American if known = small controlled Dust with High-resolution of dipole structures order of interferometric and the disk. dust and 1.2 molecules Physics, young and and (Sargent also Astronomical in Geological van interferometric disks of a 1989; in K, has Pasadena, are Pasadena, nearly circumstellar they colder JoURNAL, headings: ± the continuum the large of & have millimeter to the that size physical about for moments. the planetary Dishoeck molecular combined nH be 0.3. not Strutskie consistent are similar Mathematics P.O. stars probe molecular young molecular 2 therefore Strom "interstellar" disks 1. CS (Shu, circumstellar Society. hampered ~ the the & scales. wavelengths, edge-on. fraction This Astronomical and been regions 391 the CA are CA Box INTRODUCTION CHEMISTRY 10 Beckwith GEOFFREY molecule require same circumstellar structure 3.06 "nebular" images All the : 4 91125. Planetary millimeter-wave they 91125. Adams, star chemical L99--L103, 9513, et -10 genesis. As P et single-dish emission tested selectively rights cloud 1992) with material observations al. may Chemical with chemical provide and to al. cloud a mm 5 or of clouds physical HL 2300 should reserved. first by 1992a). cm- those measurements 1989; Astronomy, of in young show other if 1987; chemistry surrounding disk reflect Sciences, substantial in & It of observational dust A. the RA 1992 Tauri structure both detail, to step there at 3 Printed chemistry is which Lizano the HL , stringent BLAKE, assumed Leiden, continuum matter be in IN and thermodynamically and depleted Beckwith is combination June usually structure 3.06 that Society Better gradients Weintraub, millimeter-wave opacity in low-mass grain the dense depleted in thermally have Tauri, the California however. is Received aperture of CIRCUMSTELLAR California U.S.A. that physical 1 x(CS) probably the in mm, The 1 continuum of a 1987). - the constraints depletion EWINE the Galaxy for growth assumed HL tests been change circumstellar gas direction, of in properties Netherlands. exceeds onto ISM: since et studies one although 1991 = data • outer J the molecules might by the Institute stars Institute and synthesis Tau al. Infrared, coupled. Masson, N(CS)/N(H structure of = Provided of combined resides December factors F. of preso­ at 2 1990; molecules via grain inner theo­ com­ from have grain dust part onto that and is -+ ABSTRACT of VAN unity the measurements are the we on be of of of depletion similar controlled 1 unresolved other images L99 of DISHOECK, grains, 27; mantle of within with 2 at ) circumstellar by accepted DISKS: - millimeter high and observed centered E-W 400 March three NRAO SIS surements sured for & CS continuum observed interferometric lar nearest sion. and The derive tion have the 1.37 ~ x to least The Spectral Our (1-2) 2':80 Beckwith stars: of the single-dish and IRAS or comparison CS was other depletion receivers K chemistry composition opacity 8-10 3.1 mm at dipole been The in and 10.4 the CO 1992 1 CS a the (SSB). its 25-50, aperture 2-+ ' and at longer with NASA AlPS aggregation 2 x expected a CS km transition pre-main-sequence on fluxes, CS in toward AND m sources J Taurus P.A. CS/CO intensity AU March and observed. temperatures 140m 3':0 were 10- wave line flux 1, best-studied moment a = function telescopes, 6.6 material TOWARD s-t, 1991) J the cooled Two software 3-+ CS and and 8 spectra 2 ANNEILA in beam, millimeter of 13 = -16°. • CS made synthesis at and 19 this km -+ with Astrophysics In CO in Owens interferometer. the 2-+ HL respectively. N-S, 2 HL to 2, dark by ratio 3.06 perhaps 32 and 1line 2-+ dust from -+ circumstellar contrast, indicates s- 5-+ provides or to continuum be in molecules line outer Ohashi using appears in At cometary Tau 2. 1 x 1 Tauri. of package. 1 produced mm. the with 4 1 compositional , cloud turn and interferometric and I. in readily 50 circumstellar this opacity 4, and 3.06 OBSERVATIONS kinetically HL provided Valley data observations K the fluxes wavelengths SARGENT between circumstellar and CS/CO kHz a considerably regions gave dust unprojected densities Together reflects source. the wide-band the mm Even higher et TAURI a an cores, centered with Simultaneous 7-+ measure in detectable. (Beckwith comae, The al. and Radio maps A. structure disks. continuum gas-phase Seven system Data a the emissivity circumstellar = velocity (1991). 3 ratio single-dish at 6lines of synthesized 1989 the controlled continuum We J 32 having 3.06 primary sampled disks. with millimeter the simultaneously evolution, (cf. CS were survey on nature Observatory where (375 1 x configurations System of gas find baselines temperatures in more. November mm in Ohashi circumstel­ et We transitions in dust It the published resolutions interstellar cs'~b~n­ Based MHz is 'Jk· generated emission index MHz) 12"-25" al. continuum that has sources continuum beam by of both observations have of also chem­ stellar These source opacity beam disks 1986; r grain 11 the and and in filter up the et on correlator. ~ of size of combined molecules protostel­ and fact beams al. CS to (OVRO) the 2.72 map Sargent of of interest growth clouds, 3C of by banks, of 200m is varia­ 1991). emis­ mea­ mea­ 100- were 1991 been 3~15 0.15 74". and 120 the the the to of 1992ApJ...391L..99B LlOO from frequencies calibrations minimizing mm, positions served scope. ed flux 3C and of continuum December tinuum mm, were using beam source 3-2, Gaussian Observatory km therefore 13 unprocessed position 1991), 383 continuum CO In To Supporting with the s - 84, 12", at x like Figure 0.72 and HL achieve the 112 J at 1 is 445 as At 3.06 size 3.06 natural and bandwidths. emission = with except unresolved P.A. the that are Tau facility and the ± has fits 5-4 © 1-+ AU and of mm emission 3.2. flux any mm were were 1 Uranus. maps 15 estimated instrumental (CSO), main-beam American 150-200 maximum CSO at (Plate single-dish 0.60. give - 0 are for a weighting lines 1990 is pointing CS is in dust 76~7. emission mJy. 2.72 28" from SIS significant based 75 CS2-1 C CSS-4 CS3-2 CS2-1 CS7-6 CSS-4 the 13 cs CS3-2 CS2-1 subtracted, 3.1. an presented narrow we a J At 18 CO • Nom-Upper b and Subtraction and L8) from November ± 0 were and 2-1 Calibration mm The = Line continuum formal assumed receivers. emission AU. At the searched HL to The Continuum 2-t 2-1 10 2-+ upon sensitivity, in ...... OVRO efficiencies Line differences...... 3...... centered of be not observations millimeter 20", over in phase mJy, HL overall Astronomical IRAM ...... observed Tau velocity 1991 RESULTS the I 15% convolved fully a against impact upper interferometer regular the and 2~7 Tau distance uncertain the is significantly (u, The at calibrator, limits for at resolved. interferometer May of nearly and and 30m CS Emission uncertainties on v) beam same 3" the the a the are of0.61, ranges the limit CSO data, Beam wavelengths model are gray-scale simultaneously, on 1". emission the observations resolution at integrated ·Resolution by CS were main-beam Caltech comparable of CS telescope, centered 2 source velocity (Sargent the (kHz) 1000 30%. u. BLAKE, the star. soob 500 100 100 100 to yielding 500 500" 100 100 beam 140 maps 50 50 SUMMARY 50 sizes whereas (Fig. 0.57, 5-4 continuum lower Maps Society obtained IRAM the CS pc The peak contour Submillimeter images in and were and sizes were size and on 1); ranges. CS deconcolved (Elias & the than the a images. fluxes efficiencies (K VAN OF of amplitude integrated 30m in the 4~9 J when Beckwith 0.46. 7-6 is emission A. 25", SINGLE-DISH TM produc­ at 0.89 km 0.42 7.39 0.89" CS is 3C CS 0.96" 1.74" in 1.37" thereby -1-10 • always at source = stellar of 8 1978). maps x Con­ these dV s- 1989 lines only tele­ Provided 273, DISHOECK, 2.72 2-1, 3.06 and and 17", 4':2 the the 1 In ) TABLE OBSERVATIONS :;;;0.07 :;;;0.28 :;;;0.14 :;;;0.10 ::5;2.29 :s;O.ll (K) TMB 0.67 4.26 0.20 0.64 0.61 1.30 1.16 found from (Beckwith (390 displaced centered central is the NW stellar and at and the velocity range 1991). HL before s 1991). central For while the km tion. which marized 13 at toward toward T~ 1 - marginally CO At Because The 1 by VLSR IRAM. CS • NW NW < s OFF S Tau. CS No 13 and x - & Integrated first 4 (km at images sources, 0.05 in antenna Both grows 1 the CO emission position, and 700 condensation. velocity ~ • to results 2.00 1.63 1.26 1.25 1.33 ~v 1.47 1.11 HL HL SARGENT structure the emission source, in additional clump, ( in Thus, 13 OF S. s- -2',-2') 8.1 At roughly glance, 9 CO. et and The of we Table AU) the NASA 1 after HL No molecules ) Speak Tau. Tau km to (Figs. similar resolved, km al. the implying find 32 3.3. the TAU 0.07 Peak temperature, CS from of continuum 11 at is but the CS flanked (km s- 1986), continuum at s - 1. unexpected However, similar is the x 6.6 are 6.40 6.54 P.A. VLSR 6.42 6.64 6.58 Jy 7.21 7.00 CS/CO 3" 1b, 2-1 1 Single-Dish flux 3.5 the No CS K 1 fluxes Astrophysics s- the they 50 not temperatures , spectral reveal km km the overall to similar 1 also at exhibit 1c). with ) Jy kHz CS 165°. CS and and very but is CSO possible. by the s- the never to s km single-dish obtained of - and ratio 5-4 Telescope emission different a 1 that 13 back similar 1 at 3-2 somewhat additional cso cso IRAM SEST cso cso cso IRAM IRAM IRAM SEST low The IRAM IRAM 9.4 CSO, subtraction • over 1.2 west nominal peak and to morphology CO or a The s- ( CS 13 exceed and central +60", of is K, lines the and masses. 1 IRAM; brightest end, CO Nevertheless, fluxes in VLSR spatial Observations peak over dramatically of and velocity, 13 velocity 7-6 occurs with in 12 is the CO Data 0.7 fluxes HL and were source observations 0) CO Beam 1.1 = detected 0.07 condensation larger concentrations the 25 30 30" 52 20 28 28 25 12 12 17 52 emission 17 positions VLSR CS are The Jy wider (Sargent for and 2 -6-+ resolution a Tau K CS and images at detected u narrower are maps System km full K the each patterns = 3 in size central upper ( the emission than for -120", :::;; 3-+9 velocity (Ohashi orientation analysis the channel s- CS ~0.5 from 19 smaller was 1 VLSR of reach of & stellar the 1 of km Jy line vicinity the 2':8 are Beckwith the limits are at structure the Vol. and HL near to the detected km 5-4 km velocity :::;; s- -120") occurs IRAM to 2 limits. in is found 13 13 of x et maps 9 those posi­ sum­ peak 1 NW K Tau s s-1, 1 CO CO 391 • line not 5':0 km the the the the are -1, al. At Jy of in of 1992ApJ...391L..99B

@ > ~ ..,....= ~ =~ >riJ .., -0 =0 b lJ -1 c VLSR= 7 .8 kmS .... =~ 0 Q 0 L~.(CS)dV ~ rJ).- 0 OT45' ~.... / ...... q~ \ ... \~~J • cJ 0 0 orao· 0 - --·'} ·...... -·' i'

r·--···~ 0 - or15' rc• '--·-,_,., 0

46~0 44~0 45~0 44~0 43~0 46~0 45~0 44~0 RA (1950) RA (1950) RA (1950)

FIG. 1.-(a) CS J = 2-> 1 (contours) and 13 CO J = 1-> 0 (gray scale) emission from HL Tauri over the velocity range -6 to + 19 km s- 1. Contours are at 30%,45%,60%,75%, and 90% of the peak flux density, which is 2.1 Jy beam - t km s - 1• Source size and peak flux density are nearly identical to that found in the 1150 km s- 1 bandwidth continuum channel. The 13 CO gray scale runs from 0.6 to 7.0 Jy beam_, km s- 1 (Sargent & Beckwith 1991). A cross marks the position ofHL Tauri in all panels. (b) As in (a) but integrated over the velocity range 4.1-9.0 km s- 1. Contours begin at the 1.5 u level, !50 mJy beam - 1 km s- 1, and are separated by 100 mJy beam- 1 km s-t . The peak CS flux density is 0.6 Jy beam_, km s- 1. The 13 CO gray scale runs from 0.3 to 2.0 Jy beam- 1 km s- 1. (c) CS emission in the 6.6- 9.0 km s- 1 range, clearly offset from the stellar position, along with 13 CO between 4.0 and 6.7 km s - 1. The peak CS flux density is 185 mJy beam- 1. Contours begin at 60 mJy beam-' with a 30mJy beam_, interval (I u), and the 13 CO gray scale runs from 85 to 510mJy beam- 1.

BLAKE, VAN DISHOECK,& SARGENT(see 391, L!OO) 1992ApJ...391L..99B No.2, emissivity directly material. millimeter shifted fluxes fairly offset only interferometer mJy s sities s stellar fact from (Beckwith agrees example, CO a density al. or observed cumstellar disk lack on give lations 20 2-1)/T(CS 2-1 Beckwith Wilson temperature positions but beam single-dish assuming arises density one less Emerson, temperature with range T(CS these 16292-2422 -l, -l, Estimates Spectra The Our K the 1992b), even are than that surrounding spectrum 3-2 (Sargent of but the p- earlier if are or the similar models shows © from 2-1)/T(CS from positions obtained position IRAM 1992 by interferometer density well contrast indicate of characteristic the 1988). more, obtained observations most American much show 3" of velocity in estimates dust 0.6 is et Combining about 2 previously in at et index 7-6);::: & emission continuum extended at where a in dense observed bulk al. x with at observations ratios al. the of beams (Menten & (Weintraub, and few for other most in 2-1 Fuller radius. flux. of 10 we The maps. most (1990). of lower no contributes (van for Beckwith that 1990), between 0.5 disk the 24 stellar the p. a A. 3-2) HL times the find the from regions of of 10. and surface they evidence = em- 25" inferred HL of are Dust km 5 Disk of in a 2-1 4. material. the single-dish Dishoeck 4.1. the the young Moreover, CS-emitting 3.06 These than derived in Models masses of Tau 4.2. x map 1990; value 40% reveal Submillimeter the our Astronomical nH ratio et we a 25", 28", 25", emission CSO s - beam Tau INTERPRETATION the position T(CS 10 2 10 are 25" the other ratios 2 lines spectra al. opacities over emission CS such model Dust estimate 1991, 1 densities 4 ::5 and mm. 5 CS suggest Sandell, indicates predicted 3.06 . difference density long-wavelength at to em- is ratios low-density surrounding beam. 1987) at derived for close 10 a Beckwith 5-4, stellar seen of with are 2-1)/T{CS Excitation power-law most for a are molecules significantly 10 as Emissivity implies provide 2.72 5 et and The 1992), mm 3" emission circumstellar enhancement are em- 3 comparison may taken fits 5 Orion/KL al. nH 7-6 is and quite are region. very nH to beam. em- a reach closest a in arises and & of 20". TMB allowed. derived 2 a centered disk for continuum from flux to 1992b). 2 3 SEST in objects ~ very unity. gives central the • constrain single-dish T ranges Duncan an at significant the Even 3 & line similar, the ~ Society the 10 1.37 The sensitive is Tau (Olano, such molecular unity 5-4);::: seen mass distributions the of For nearby from average 0.2 4 different the to consistent Sargent broader p circumstellar strength. spectrum circumstellar infrared (Blake mass em- Excitation The resulting 75 The thermal mm, at of (van at CS stellar = disks from K HL such toward as temperatures at disk Mn at 'lkinetic the 1.2 although power-law optically 1989; VLSR mJy to P; 15 3 source Hco+; Walmsley, best compact VLSR TMC-1 data r • is 112 to upper Dishoeck CS Tau • H et These = the such ± from = 10 cloud. it IRAM line models and and consistent 1991). as 2 ~ and A Provided emission the al. 0.10 with with fit 0.3. 9 in 14 antenna HL and ~ may = TOWARD column Adams, refer CS 6.6 for similar in AU size calcu­ at as 1987), to IRAS em- limits 8 offset a those T(CS 10 disk, sub­ dust only den­ This core red­ disk thin Tau M For 2-1 980 cir­ km km 55" the the the the the the the CS fits By K, be to & of of of in et 0 3 by HL (Sargent cantly the filling distribution tation. region somewhat emitting corresponds constrain inferred implausible. Beckwith tened, nondetection are emission adopt extended decreasing 1989). didates CSO likely These the molecular radius models, warmest, perature sion spectra surrounding CS at at CS extended optically opacity. depths derived Tdust 20 that where the the the high beam. provided pretation. 'lkinetic the If The Our Peak least K 1 densities 2-1/5-4line part 1.3-1. continuum-subtracted clumps abundance TAURI molecular the x(CS) arising ~50 densities. AU 7-6 and Thus, N(CS)/Ne factor The ratios a and also = to NASA CS temperature of for more The studied yield r this from from "hollow" CS of optical We gas & originates. 50 is over thin. 7 ;::: with to upper et molecular that nH 3" Using be the cloud K abundance larger = inferred the appears the to km is incompatible Beckwith seen 450 from emission K, would 2 13 at is al. can is should to are about or N(CS)/N(H optically dark is N(H continuum (Cohen of 15 ~ substantially compact a many CO circumstellar source Characteristic a extremely Especially s comparable 12 the uniform. least by Astrophysics cloudjcircumstellar TMB found 0.02, 1989), -l AU comparison limit less, depths 10 ratio CS consistent Kat photospheric similar reconcile CO in 3 reach a size. 2 CO) Beckwith 4 structure, ) (Table cloud, place emission lines CS to region limits :::;; 10 the be ~ arcseconds, cm- (3" up 5-4 cloud the implying is 1-+ indicates 4.3. 1991). is r 1983; 0.9 10 be in physical a thick (2-3) in Since single-dish high ~ 3.5 = to optically radius). interferometer or arguments, for ;::: somewhat Lower are 2 the measurements. 3 cold, is the em- O.ot. IRAM viewed Taurus 0 the with ) are K 1 400 the CS 1 these where a is images in ), ~ to with significant. transition. arise and of enough material higher in the et If x in radius CS-emitting implying Beckwith is N(CS) with not with disk the NW (1-2) also line Abundance our 3 the CSO AU. temperature 10 'Jk the al. the 2-1/7-6 the a Av a thought conditions. at The temperatures two must thermalized, CS thermal 1 Data 4':6 21 nearly upper nH disk thin, netic diameter too (1990), and adopted widths from and column models, gas-phase consistent is ~ clump, the OVRO CS disk Midplane 100 larger x of 2 cm- we given ~ to 13 disk consistent determinations 2.5-4 offset 2 where ::5 beam. ::5 10- have optically a CO 140 (5 is -+ other emission the molecular observed The thermalize et conclude map Adopting 10 AU System ;::: visual limit edge-on 15 temperature colder Of 2 to ± HL probably 1 region excitation for 8 interface. 6 which al. source averaged density AU 1 beam. , observed with dust the and of K. nH of 3) emission mag. em- nearly consistent 13 the of Thus, be in In (Wood cannot CS with molecular Tau the it 2 temperatures CO of the 1986), x Such extinction order would 300 (1" the ::5 must predicted with bulk optically temperature particular, C thick. similar in material. at 3 10 depleted CO TMB:::;; that (Cohen appears cold Similarly, , cloud CS radius 10 For 18 is the a for at the 1-+ we that 50 same distances 13 Kat this highly 0 a among 5 CS over only line & In have 0':7 only of the this be HL emission, source em- from cm- disk the structure permit CS low 'lk find CS material with 0 J For the the is, 0.14 central Morfill signifi­ optical 1 can simple clouds source netic 1 line beam. = is ratios in beam if inter­ 1983; Tau), emis­ other a if thick to L101 from exci­ if tem­ 3 near 2 can­ dust very flat­ AU, that For CO HL • 2-1 , not the the 30" the the the are the the the the we be be so of of in ~ K is a 1992ApJ...391L..99B able self-absorption able center. Tau Tau distributed ized. velocities mass TaujXZ mag Absorption ratio obtained a ometer 1990). L102 A( years ratio subtraction a CSf lower Thus, ranges both N NW surrounding involve dropped growth is interesting tion near Sargent single-dish al. gas demonstrate interstellar into toward bound cantly distribution) argue circumstellar 10 depletion disk. gas-phase For nature repository beams 10-9. other factor 2 between optically A If The 13 8 Grain , 1989). 13 CO with phase optically in the em- or rough CO The have and chemical of resides 50 of of CO to molecules. Much While than for is This we onto to fluxes, the most which their of the via HL CO the 1991). 10 13 16 K, grains 1-0) Tau mantle significantly to respect by ratio 3 by The S in the of flux , been CO cs;co a 4 © the find 0.1 atomic to central thin, of direct and larger depletion. clumps estimate measurements, effects the virtually dust may Tau, molecular and the less however, (Sargent grains, yr it the comparing HL will S. Einstein true that and closer likely = cs;co note region, American thick and rather disk. sulfur sample and is emission and of ratio at continuum In value derived 267. in that 12 N(CS)/Ne the depletion reaction difficult than Tau. to help 0.06 integrated while is condense densities the deposition the CO than that abundance by either will channels that dynamical ratio oxygen the are the 1.0, or emission Either consistent observed CS to of fiat is Q(CS)/Q(CO) of in the & all assuming offset smaller filling A-values. visual found explain abundance with In It 30 and the it not the partition molecular approximately the consistent solid solid Beckwith the the and the star (Cohen is the loss molecules has may value has to case, contrast, lines yr CS be optically time bulk of CS 3 grain abundance the Astronomical subtraction emission 12 determine that of CS onto CO) outer central factor fluxes integrated for of for extinctions if they been been H of CO formation important in + CO 10 than processes flux also the time difference. grain the are maps a of 2 the that CS with scales CS CS 0 abundance 5 0 both & 13 the of functions = is, ~ em- p features lack ratio are 1991). cloud, grains. and depletion CO, ratios with lowered -+ transformed the 13 features reflect regions is optically that of scales. Kuhi is onto high-resolution has compared 1.0. except the x 4 has thick the with extended star mantles CO where then CO substantial (and molecules, of the therefore range 3 CS/CO the of CS 0.1 a resulting of for is CS For those for circumstellar molecules for for 10- order in grain been of provide it process and CS dipole 1979; (r + CS compositional x(CS) exact In approximately We At simply and large, BLAKE, have will is species without of 13 (Q) have sticking therefore substantially and circumstellar most order 13 < S, in the 4 from dust thin emission likely CO. densities time , form emission this CS Society CO derived the to molecular mantles 5-10 flux depleted the with believe 2. the and some occur chemically Beckwith location not moment comparable larger 13 ~ been its the in a that The sources related of and (Beckwith grain temperatures The well or circumstellar Av context CO are CS a ratios rough such the disk scales that filter A(CS the continuum coefficients subsequent (Whittet the conversion VAN AU), for line few ~ the near of observed 25 observed material. similarly near from thermal­ emission compact closer over interfer­ that in ultimate or, velocity inverse notice­ 3.2-3.5 system can mantle signifi­ as higher diffuse • of evolu­ about to in bank. in cloud ratios upper 3"-4" again 10- times times et 2-1)/ disks mass if have tern- it into line DISHOECK, HL HL Provided H the the the 10 the the the be al. to to et & 2 is 4 5 , . fore depletion comets lengths. vational tion the high properties peratures possess (Lunine for 0.02-0.2. appears abundance al. cantly large clouds abundance through ranted. cs2 and dissociation CS is the thought uncertain). formed diately continuum in gives When the ments, the models 13 pyrite finally 10- average and evolution. of dust or H molecular however, CS ISM thetic CO 2 Since assumed, We In Our comets 0.1 H S, by CS, mantles once 1981; available 9 molecular versus suffer of then laboratory 2 is the emissivity H CS/ & to S/H an is have ~50, grain combined (Barshay M the larger trapped a the observations surrounding and 2 therefore but of presumably the into CS the CS, study optical their CS it SARGENT to 10- inner p best 0 1989). to Some upper converted are that 2 is the Jackson, 3 over comparable cloud enters , innermost both value IfH CO CO ~ in and roughly presented highest be NASA are in with in outer H mantles and the and molecular of 8 vary this H high sulfur . IR ultraviolet (2-20) than 2 the explained of CS sulfur these part 2 A harmony a S/H 2 CS hydrogen temporal in ratio S, index depth larger from & cometary The in CS 0/H limit experiments surrounding with and of CS high the daughter CO interstellar possible respect would icy regions can disk 2 enough transported from Lewis 2 cometary , 1.2 the of grain 2 line-emission is CS/H Butterworth, into 0 HL formed, of Astrophysics are observations presolar which x 2 may submillimeter CS disk reservoir on dust materials high previous dipole have to the of as thought be ~ ~ to ± 10- the size with cloud gas Tauri. needed 5. lines carbon the the ih previous with 10- 0.002 comet the and compared lead rich. by 0.3 1976). found mantle regions carried 2 to solar for reflect abundance of scenario to opacity 0 CS spatial 9 product SUMMARY along , been scales, phase dust surfaces moment that a T is 6 cs which the drive grain nebula. source ~ edge-on ices HL spatial on (Feldman abundance. and to (the The millimeter to (Blockelee-Morvan comparison to back derived Tauri nebula (2-10) (Stevenson The to disulfide, in to the depleted precludes the binding found 10- into of principal Tauri detected maps with be and & of CS/ or near address value CO the flux for 3.06 even is H growth resulting cometary the to comet observed selective size to variations HL transformed of 5 Ballard molecules, sulfur 2 processing Data circumstellar again ratio orientations. 13 the CS spectral CS x (r and the along emission H particles from disk interstellar presolar are of mm the the in CO et 10- 2 ~ found at Tauri. of continuum energies, S It or into inner abundance onto al. the comets origin the in complete the 1990). consistent with suggests 5-10 constituent, emission of comparable outer with chemistry forms or thermal roughly ~ System millimeter radiative 4 appears HL possibly from with incorporation 1986; • 1986). H various atmospheres material the 0.05-2, H ultimate direct resolution Assuming are compositional grain 2 in nebula, which lines However, in nebula 2 Tau. AU), S in S. Searches CO/H of into nebula, a et derived seems the may dust abundance The the interstellar also disks the Weaver However, disk the CS/H cometary dust retention al. measure­ core The observa­ 200 from unlikely, Vol. H The remains mantles most transfer bulk H tend in comets signifi­ photo­ diffuse obser­ imme­ fate where 2 grains wave­ found there­ 1990); trans­ to 2 H coma 2 CS mass have 0 war­ CO/ map dust S AU. syn­ and 2 CO and 2 low 391 CS the the the the for 0, to or = ~ of et of of of is if 1992ApJ...391L..99B in most "canonical" sion sulfur-containing sion smaller also in part. dust dances No.2, 105 Cohen, Cohen, Jackson, Barshay, Beckwith, Beckwilh, Beckwilh, Beckwith, Blake, Bockelee-Morvan, Adams, Elias, Lunine, Feldman, Ohashi, Menten, ApJ, 343, Evolution Halley's B., 143 the other em & in © argue J. grain is G. consistent The M., M. gas Phillips, F. H. J. N. - aperture 1992 are K. W. S. filling American A., optically I. S. S. P. 3 C., S. S. 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