Ionized Gaseous Nebulae (Mexico City, 21-24 November 2000) Editors: William Henney, José Franco, Marco Martos, & Miriam Peña ages Wilson to large ture. the Mink grams blobs, man tricate, complicated, ob sho ample, rings Lic tographic clues repro with the high Key differen R diagnostics Mapas iones n largos tries require complicadas The problema, grandes imaging uestro evMexAA o 2 1 jects k wn Long Recen Ch UCLA, Moun Hubble y HIGH Wor small extremely with of o adaptiv duced Observ to de resolution to of ungbuk ob wski and Unfortunately tiemp with planetary t as de a who planetary brok app traba telescopios ds: this with jects. hierro NGC giv from ago, t t long the surv Division secured alta ansae and uno Wilson studies who Sp and A e eared in (Serie en an os atory secured e y fact National P TOMIC exotic jo the more DISPERSION Curtis ac their ey exp optics Aller The son alomar complicated 2392, structure de 1. para resoluci´ image deb the e a de obtained radio indicativ man with Hubble of nebulae, INTR nebulae osure diagnostic T orderly exp 2.5-m b de and m of next e alta con elesc imagined than y Astronom ob (1956, effects este high uy (1918) Univ at obtener the y planetary the Mink osiciones, Confer 5-meter rotator the jects. D on maps, y optica ´ ODUCTION large found ev diferen disp big op A reflector. ears of ersit Sp , diagn´ tan “Eskimo” e mono disp scale en T en e 36 to there o one Fig. of b ac , shap A of adv completed wski ersi´ y talizing y encias) oth p There HST 00 with simplicit telescop ago. , radio, e esp a ersion b and ossibilit at — T adaptiv ostico. Korea. bad tes that direct Crossley m ance c e T more on VI of elescop a nebulae es hromatic the elesc w ectros ust un the ´ and PLANET often , Astroph SPECTRA I. a The de ere the of revisamos and seeing w , im´ large Nebula, w although con 12). inner La slitless secure suggestions planetary 12 complex ere coude es op la y b as y a imaging irregularities, agenes the e extremely Crossley y wrence e of m fan long observ con , clearly simplicidad Reflector and ac (PNs) ysics. telescopio inadequate Wilson 95–99 uestran and telescopic direct iron and hiev first tastically w AR sp sp fo alta ere b ago. for brev y cus ectra observ ations directas struc- ectro- man ed outer H. Y ions nebulae ha with pho- with Olin (2002) w im- to ABSTRA are ex- for resoluci´ in- RESUMEN b NEBULAE T v que emen Aller as at F of y y o e o grandes, based of OR ap con ations address las high erture con 1 te rev que and on nebulosas PLANET el on feren bip grees et bip tually nary originally difficult suc tion, orderly NGC magnetized tions, or celestial up A but, A mo riv somewhat cally CT ealed with el spatial GB GB espacial diagn´ para se ed adaptiv the Siek to our al. del h olar, olar What Studies F T sho — alas or t as elesc b las stars symmetric of reac from shell adaptiv 2440, through star p and an etter 1998). complexit c of recen observ ostico TECHNIQUES: the osition Hyung structures. structures k collimation.” most rotating, to resolution imaginaba whirling man planetarias extremely opio h one describ Sun w e y w bulldozed and comfortable with “proto-t ac the a fain than of AR optics are winds t e alta v hiev y e ar high es needs del ha Planetary 2 the angles Kw These Esp particularly optics PNs outer t in esp y Y las v accretion wind running a ed features. w e disp episo e plasma debris ok—a in acial high observ fraction are are ards disp and ecially in yp to complex NEBULA tiemp estructuras as exhibit is ph tienen from b en ersi´ at authors V e” ground rely extremely from a y sho dic in ersion ysical resolution arious high v bac with Hubble “classical” large v N-ric the elop rather roughly ations. on. nebulae, SPECTR o y out olv wn outflo engaging. the disks, W on of k atr´ structures a formas highly the p ed e disp w rapidly e to a h conditions the to p olyp sp based T radio-frequency telescop scenarios core, as. remark briefly ard of osibilidad w second P am in ws d y ectroscopic than cen b ards eim ersion. high ´ MHD ebiles. the spherical radio e STUDIES simple olar observ P bi some through with extremadamen man bip in OSCOPIC tral as ara emerging optical ´ en b mo This tricate review highly fundamen the ert es, exp spatial reminiscen of ob olar that y maps, se in atender mo star, ving differen of Basados aciones and It arc. ject T are v de theoretical ected hot of planetary requieren olving yp dels PN the also shell w the observ “sev utilizar ev plasma geome- ob greatly (L´ e us setting spheri- , ork. resolu- This core— at direct HST I is olv more from op t tally jects with ma este co PN, eral con dif- t felt de- de- ac- bi- en ed 95 te ez a- of ol is y , Ionized Gaseous Nebulae (Mexico City, 21-24 November 2000) Editors: William Henney, José Franco, Marco Martos, & Miriam Peña 96 comp quan ing ing that b mo densities promising m e.g., coude dicted mean b W b spread 0.15 b Ruiz will and the slit sp W greater these sp of far ing cal Observ surrounding ature, in P the use mo 90 tion and a (P melange this y een eam e 2. eim uc e e traditional ectrum ectrograph eim T con del del, the useful Th The F y observ la cry length true is resolution observing a e are h use CHALLENGE not 2 ears of in or comparison tit A ˚ b found Garc & ositions alw y ma alw n closer b square tributing rev through us, ert pixels tricacy fo T ers b atory do atoms um y ert, appropriate in this at whic led L´ than e from y a giv cus. y extreme complexit a . to of a ealed. op es and ago. ´ as ys ıa-Segura, as ations. (1967) whic electron the of b 640 ys sometimes 885 Nor scenarios of e Luridiana, from er to study ez tak jets to . h not the a found necessarily a fluctuation w act a . 4 that among F their coude or temp photoionization on pro of W hop susp µ of 2000). the h ould 00 gaseous nm. the zeroth or e will hot Actually v Their m The e tak and is scop reflects in suc olume to the stars other the ga cedure—the structural the a With w efully y truth. co to slit giv temp used. ect PN. eratures. the TO imagined v it e diagnostics. e b b Because h slit star of v sp e that F v P e simple o e ha shells CCD accoun exist sho er en giv arious criteria. 3-m order, ranco, ost sp eim & a whic that the of ectrograph that nebula. ab temp nebular elemen v THE Hyung width , erature other the of the the ectra can metho e e b c T Th is Wh our out w and k b ha y used orres-P phenomena the that T Shane h e c ert and in unsatisfactory us correct are w t e hip idea erature v photoionization com ionization complexit range of y? initial represen & tak These SPECTR amoun observ 0.05 e simplicit throughout a in arrangemen use mo ts increase a of correct m v one analysis d This (1994) o the ma b throughout The es parameters. L´ required is obtain ev e real Th v bined ust with een of 640 for op del eim erlapping of telescop one aluating a A ˚ y ab in observ 379 us Hamilton electron photo-ionization ations a ez will t fluctuation is photoionization b to slice arcs, rev calculating PN b at out to prop t µ e spherical to y their fluctuation y one has ert w an OSCOPIST con m, can 2000; stages, spread the to considerably accoun whic an eal b 360 e some b of 1.2 a e 1.75 for the es . imp e through ts are 1995). osed flat-fields, tributions e the increases, 1005 describ wishes v less a c distribu- use PN differen orders rev some 00 the temp a h ariation nm hemical v at suc It mo ALLER practi- Rey radiat- ec eraged study- ortan It at p seems but pixels in t limit- 80 ealed encil than helle (see, shell h Lic long ma nm. PN. pre- dels is and and has the the T es- er- ed as to or or of it e k y a a a t t . & HYUNG only ga for larger mo p of factor observ the t or determination fined strata the et redw lev with p T ies IR. tron auroral b yield plorer example, the the densit necting a slits. primarily ratios [Ne trum N the reac d-electrons. single planetary as N dep w eratures, ortan oth o precision e e v o v al. els transauroral in dels get of e With With Most differen and ends arious and 3727/3729 I auroral highest h But requiremen forbidden examples: I ard [O a mo temp I What to T are 1995). PN atomic y [O fain ]. p ational of of (see, w t is b clue than e oin I lo to of w T oth e T the derate b I almost no the I and of that the I a e of w-lying e e high the I ecause the The can t gro on ] nebulae , iron eratures. the I . t. nebular N t w as big ]; whic to for transition w 91.2 features excitation t is N optical the ying temp Th that e in w The electron ould This N with nebular p parameters 3726/3729 temp 2.1 e forbidden reac required N fron there gas. ratio and tensit lines sp is example, A spread ions. 3 ts accuracy e and more us, Plasma t h en e ions yp -v nm. . ectral it as for alw lev w the temp ga eratures of h t. tirely an Plasma alues in lik the can eratures T lines e ere for enables to T region, v to of y in els has e v ticipated in our a transitions Since the e e e inclusiv Initially , olv plasma used densit ys 7319 The transitions), 7319+7330 get in p for primarily a the in for erature p a In to [S the giv resolution in oten v diagnostics on 2 of the e lines b and without biased ailable. line electron single ternational observing. same the I t [O een useful terms a and ha equiv e I Diagnostics and Lyman w accessible N a and ] for from w sp gotten y us detailed tial discussions o significan v e , I or e e , p ratio diagnostics collision radiating I e ectrum. n of but great 2 I and and from do our p to diagnostic compare densities. um ] emitting alen ion 7330, a [O with to 4 or of w (whic T 310 for Another the es suc densities to observ v e e w and can cut-off b if from the I equiv , demanding efforts of ariet p the w t I w ards ers, not and progress and ]; photoionization 4 study 3726+3729 w h W Ultra obtaining nm e p-electrons: the ould p infrared w t [O h e configuration. other 3 b the difficult strengths and e e can As la y one temp clues ha b observ e the alw alen e [O the the la I can w the to will y lo do y I just Originally of imp calculated violet v studies need w ] lines ers, e y our of abilit P w and e get a I ers. wn p the of dep ere ratios t I eim on can ys er sp criteria use auroral erature as hottest 4 ] a on c p- to ortan to whic is whic y e ho m so stud- sp ectra as lying for b ha b ends tem- b elec- high near con- con- b y and also and and Ex- uc im- F the oth oth the oth the the ose get ec- ert for do p v to or of in in h h h a e 2 t , Ionized Gaseous Nebulae (Mexico City, 21-24 November 2000) Editors: William Henney, José Franco, Marco Martos, & Miriam Peña tion. lines configuration tain b group, 4363/5007 T observ rather Keenan from from from et of deriv large. ions: the esp our distinguished the 6741 abundance gaseous 12 arise that T of excitation the of ously NGC [Ne configurations strata. p [O [Ne relativ as e ossible, e ([C 000 attac al. p seems I PN, ions ecially Un Abundance The Some ]. one V IV made abundance ossible ignorance then , e complete from I forbidden lines ], some as Thanks w (1995) the [S 7009 I ] til ely ed Should w K corrections I than w ere T He ]) k hand of of and e et in I nebulae w e able vs. preferably real; I recen b w ], and should PNs tricate isothermal. ell w observ no 3.2 in y collision I co un al. whic greatly 3. a and to as abnormally I has determinations. ob ork v , [O 6800 Wyse that w recommend ol [O ailable til the w particularly . as 1 DIA H often get and (1995 an prop jects b tly with other 3.1 e I collision A of of ha compares h lines? region suc et a I I I data of obtain , ], on I ational bundanc collision w determinations same analogous K. try I w structures v T . O higher it the GNOSTIC from [O this ] to fundamen as e h osed (1942). differing [Ne e een Seaton p ++ in that strengths. allo has space suc zone; et Some the 3 ions? and I al to data as on hindered I the most ], . ma Configur at IV seq.). sp l The h ws as the ric differen in pro The errors. strengths obtain relev [O found temp NGC temp e the w N ], ectral T y the to as mono high h of strengths absorption, e 1945 e Determination us NGC Not e In ha (1954). v I [Cl (Aller [O correction striking high tal ], the excitation, v of use en in in F the difference an infrared NGC CRITERIA alues v end to erature or other erature and I e I resolution from ations t in the PN m Y 2440 c v I region. as t N. The I efforts and atomic I a T hromatic T I ery get example, et ] HIGH parameters ] uc 7662 comp excitation e e the profound of man of for lines [S and obtained 1956) v P a requires h discrepancy found 2440 w arious [O difficult applied eim An general the w the I w large suggest progress ords, determination I than fine early as p b ]. osition ere y of elemen while is seems I [Ar 3 e DISPERSION I e.g., parameters, b to I diagnostics diagnostics analysis Sim ma the often imaging ert ] his and applied radiations from configura- suggested spread structure P and radiating a IV compute m effect the da y eim that jor v from shell to ultane- Belfast outline for the [O ust ailable (1978) t ]. ts to a to ys yp could t NGC quite from C yp PNs lo ma b axis I See hot the ob- e I ert w b on w- on b p I p to I in as of es of in I ], y y e e 3 3 I I SPECTRA larly whic actually abundance (A sho iron fact deal of stars no e.g., buy c and sisten nen sitions state. structural the b more pro in w tions whic (hence tronic son These as (Netzer those w Orion, sho times the with planetaries, regions. I are ion hemical (4861) et e e v abundances GNs) app a w w w note duce a Man One In It t. lines usually ha problem. 1993). 4. aforemen h h this ev complicated ions, more een Ab that remnan in strong, t that ha tigh around some has w with PN v ears for F Sulfur presumably collisions, olution SOME Rubin of dogma tensities e In the eak ell e y v of 1988; = b v F man in the and assertion e comp I tly stars The aries for F elo celestial OR esp I the will long the 100, are iron and v in to 30. e SPECTRA the resp suc lines 0.1, iron “iron ery where lines w. I ts, 3d- y b whilst I tioned ecially 7 b has stars quasars et Netzer [F factors some REMARKS PNS ound. in capable ha of of same largely h ositions e and from terms sp eV although kinematics b ect Probably there nearly 0.2, e and up the al. een ionic are as v and PN the and ectra PN · fashion. a of e forest”) are · found sources Shields originate nebulae. · to (1997) to suc to S 3p lines ] situation one or F PN esp complications excited situation in In kno univ F & that whic lines 4s-electrons b e recom fall seems or largely displa the b e 4 lines. 0.3 the of efore of h OF with I ev the Willis e effect, ecially I part configuration wn ions most themselv Mg the IC en kno ersal of as the (cf. ev in h greatly Configurations Sun suc suggest or are same w ON in 40’s PLANET details, olving binations result y the elemen the 351, as less. that b w Heretics the from to wn are of excited They ev F with h Viotti y from c the e 1983; of unexp prominen sev app uniformit e hemical activ THE in the and en radiation, as the 1500–4000 exist can precision energy is ab the IC m Sun. hindered eral the W es as one sp in ears the F η diffuse in 1.00 tied uc ts out there arising first 50’s are shell e F e e Na 418, 1988), determine disadv ectra ARIES ectedly to Carinae, detectable to IR b n e h who is galactic measured of sp a but lo y of umerous most as I v the ON up to I PN. more depleted w not whic and on t comp w ectra fluorescence comp y e to Aside comparable NGC to the is to its as nebula. & w lik sp configura- of from refused radiation, obtain of the in an structure A ˚ from lo the and e ION another, also particu- ectra the in Johans- A e h w massiv comp [F ok ground hottest taged. b promi- region, grains, osition etition QSOs. sup eak of teract 3d n is study eliev e 2440, great scale their from uclei lines elec- lines PNs iron p in VI 6 PN the the the ten er- er- 97 In to to as in 4s o- of I e e ] Ionized Gaseous Nebulae (Mexico City, 21-24 November 2000) Editors: William Henney, José Franco, Marco Martos, & Miriam Peña NGC 98 6790, PN NGC 3639, atoms cen iron jects. sho diagnostic to example cade role where consider, grains & alen tical Not tion degree descend the tim T densit conjunction energy the One ? , Czyzak 4 t w um A Note in r t although distance D (Chen only states, ma excitation can , lines. to termediate a NGC 6537, p-electrons. 0 y and Some determination 7027, [F and and are , b distribution situations, n y and y e an a to 4 um ma that use are These F VI exist for direct Hb 1983). raised not p & W 0 the NGC NGC IC Nebula NGC NGC NGC NGC IC NGC NGC NGC NGC 6818, but in b Of y PN ] , ossibilities NGC with temp there from er the and Pradhan they ( termediate example, and 12. b with 419 2165 r b ground course sp almost are e ), of ELECTR m e suc capture 4 7662 7027 6572 7009 6741 2440 6790 6884 6818 from observ NGC 6543, W observ ectral the [F erature uc P where W iron w the 7662, w a 4 P lik h e esterlund-Smith in G equiv h e lev ere e ossibilities large VI of as ely 0 appropriate can of found atoms the 2000). star the lev el all ion 6884, greater NGC I lev ed NGC able lines the extremely [F ] from the in N IC alen b lev ON are el as n e set in y v stellar els e 4 in lines. 11 11 11 11 um to VI olv F with [O F el, collisions 4846, and at iron F usual, tensities un t NGC 6572, pla the can e By TEMPERA 40 constrain 000 500 300 500 I the e from the ed ground b ], d-electrons I than all. abundance usually 4 er o ] ion ys P and ccur T with radiativ the where gaseous ma sp also con equations of radiating e w IC 6886, a NGC from Still, T ectrum, lines whic are eak y 25 exist p v ? NGC emission tin and of errors ery lev for ossible 4997, reside b 12 12 12 11 describ ts strong 9 7 [S in e uum. the the in h in the NGC whic e 6741, 650 el in 500 TURES 950 400 500 750 on stage. [F imp excited I to for pumping, the they there I 6741 some some is of ] all e of and electron v to BD+30 fluores- lines in a N ALLER I ioniza- olume. h ortan equiv- tric In es F I (Aller of atomic lesser 7009, NGC e ] LMC these solv e solid they , also cas- but r PN ob- op- op- the VI An are ky T to T IN in 16 is 19 19 e 11 11 11 e 10 12 11 t I ABLE . , [O 8 9 500 500 750 300 000 SOME constan 750 750 750 670 000 750 & I I ] HYUNG a a a tak ultimately zone bly plex b are nebula T of temp with ture as lines imaging. is the (b) data an length men [F 4945/5721 the of the is metho fully 1 e e e ts esp v REPRESENT the the Z in e successful I The W estimate ery no b 4607–5412 17 expressions ted data I or of p [Ar 12 11 13 I 12 12 erature. in And ey 18 11 are of exploit of ecially the e suc ] olyp w ds 5. 3d radiating to co observ PN via fine-structure ond prominen 500 750 050 useful 900 300 200 700 m neutral b high IV b dense, h v SOME 6 more An y with ust, successfully HST accoun ecoming erage or olar a w ] a sp and ground go our theoretical e in w ations. ectroscop attempt of CI the accuracy only will o (Keenan a teresting , again, ob A ˚ useful go d y 5159/5721 capabilities for from lo atoms N or A Cygni. CONCLUDING tly t region [Ne 19 21 19 as 13 spatial adv jects o range. w TIVE e ha also d a , for configuration adaptiv the 800 v 500 980 500 to (Keenan v excitation IV w an imaging, ailable 5 the e in should emphasize y D, e w suc rather giv and ] to tages, mo the and & plasma (Viotti and dep e A NEBULAE com ma The resolution. infrared 3 resort h e t Norrington del, m P, ratio. e c y molecules go ends as at high sp and ust hanges get bination b 12 optics relativ et simple 3 they o ev ectral e NGC an the suc H, d 1988). 14 diagnostics, 12 500,6800 12 10 12 10 14 PN 11 11 [O to made aluate al. a 9800 (c) on ha excitations dep diagnostics. Of REMARKS endea that h 3 to 400 500 500 000 200 900 000 000 400 presen mo fix I F, v m I (a) e 1993) as tec required 2440 e mono IC I end iron resolution. the ob In ] ust p dels. v and to on (Kw 1991). sp ariables opulations hniques to is v a T jects. fact 4997 or e explain ultra t ectroscopic wide on b the are ions, attainable c largely use ok time, 3 e that hromatic from W G the N [F supple- the b proba- e violet, stellar 1999). These Giv sho w terms Com- e y e these m F suc ma that a VI size and but e the the the ust v fu- T ws en in of I e- I h y o I ] Ionized Gaseous Nebulae (Mexico City, 21-24 November 2000) Editors: William Henney, José Franco, Marco Martos, & Miriam Peña P ing (1990) easily brigh list tories. Th its ob in est tical ob man structure, p ture and trum nosit amenable most more tensiv P for regions. that ob on els cate La so as imp our Aller, 06372-01 Siek Aller, Aller, No. Krf er ossibly erhaps wrence ject jects ject the that us M2-9 the & high and PN NGC 361-763, California This concen of ortance b limit. w y 2000-1-113-001- the No. and ev y; relev sp tness Hyung: efore Hall) it ork amenable to L. ely (see L. L. of target to past olution and suc mo with sp ectrum, its In stricter is a complete , H., densit total H. our H., offer. It ric whic 2000-015-DP0445, them observ researc 95A. 7027 at ectrum laid mind. an more trinsically to not H. dels. h kinematics, trating It cen Aller and our h references ma 1956, but & ma t Ross, as Korea mo this an efforts Aller: has ob sp h Departmen observ surprising tral 90095–1562, out mass Czyzak, y of y has y ey NGC NGC complete classical deling. ectrum, highest constrain ma ed jects. see, to in also h et and lie pro complicated stage kno one Gaseous Our es. mo teresting J. REFERENCES for star on ob theoretical y w b UCLA, (h al. should near 5, of ational v e.g., een E., v as wn. y b dels ric yung@k jects; e 7662 of 6302 A us. these ery oung therein. and W e S. task and 1981 the ma it These the h densities while Omara, fruitful supp the that e n ob examined t ts J. the picture F Key ma um repro Nebulae sp luminous y prop probable or of start U.S.A. PN (Harrington Division has b they jects mo 1983, ma structure ob is b ha data ectrum and highest y y b b orted ao.re.kr). maxim etter it a es, are Science PN. NGC y er mo jects v to deling STScI y b NGC ose description ducing ma has an e B. e in put with b the Aller, extensiv references ApJS, of obtained. among kno b deling. HIGH are construct e w (London: y ([email protected]). W een a J., in kno tracing in p put ell ev 7662 whic these in of NGC um has b in firm e erhaps few teresting 6302 wn K of more Gran a e and olutionary man & Education, trinsic certainly Astronom wn their OSEF v to & part 51, more near on ob et ery of DISPERSION h p the Key among seems candidates, The ely constrain erhaps dra F PNs is 7027 y are ric jects ob t al. of PN 211 the the eib complete Chapman therein). Of massiv the for es, most No. sp sp another the studied h w b jects regular the surface reason 1982), Gran elman ev y struc- ectra, ectral equal lumi- mo come in sp more C. up ha ric with suc suc y PN. olv- his- AR up- the op- the tri- ec- in- and v Ch d- h- D. ts e, is h h a e t ungbuk Astroph SPECTRA P Netzer, Netzer, Na L´ Viotti, Wyse, Key Seaton, Kw Keenan, Rubin, Keenan, Keenan, Keenan. P Rey Hyung, Keenan, Harrington, Keenan, Chen, Curtis, Garc op eim eim v National ok, Vittone, 138, Vittone, 138, mation mation 1998, 4551 P K. 1995, ed. & gins W 199, RevMexAA, ASP), RAS, McKenna, H. 1981, Kastner, ASP ulae es-Ruiz, ez, es, e, ysics, ´ ASP ıa-Segura, b b arren, S. ert, ert, G., 1982, L., G. A. Y. S. J. R. R., C. H. H., S. H. to M. 331 247 Asymmetrical I Rappap F. F. F. F. Conf. , F. I: F ApJ, P MNRAS, 281, F. 1999, X., A., B. Cra & T 235 M., 8371 M. 102, 1994, 1988, . . . D. Microstructures, ASP OR D., of of 1988, et P J. F & erzian P P P & & G. P M., J. MNRAS Johansson, 1978, N. 1999, 1998, ., rom 1942, P ., ., ., & Univ Meaburn, wford, ., F F al. 1918, 1967, Willis, 1954, Luridiana, 1073 ., M. M. F. Aller, Aller, 493, e e P , & et Aller, 59 PNS A. Ser. G., Planetary Math Aller, Pradhan, Sok 31, ort ., 107, & ApJS, I I in Aller, 1997, in I I C., Norrington, F F Origins al. (Dordrec 1993, Seaton, ersit in MNRAS MNRAS ApJ, riedjung riedjung L´ Lines Lines 197, IA F er, 803 Publ. IA ApJ, (San 147 MNRAS, 199, op F. ranco, 1997, L. 148 IA B. L. & L. 199, U U Sciences L. ez, ApJ, Planetary & y 90, L., H., U J., L. 95 Ramsb S. H., , J. ApJ, 95, Collo H., Collo V., outside outside F Asymmetrical 156, H., S. A. to Lic 48 Symp. Nebulae J. 517 rancisco: M. 1993, 1983, & ApJ, 119 Bryce, h H., Hyung, (Dordrec (Dordrec eds. J., 304, 295, Hyung, 356 t: 479, & & Rappap Microstructures, k A. K. Hyung, Ramsb Gaesin-dong, quium 114, 410, P quium 825 J., Reidel), Obs. T ottom, & . F Bell, Building, 2000, J. 2000, orres-P 487, eib H. 27 683 A&A, L L ApJ, 76, 332 Nebulae Adams, L´ TE, TE, M., H. 154 430 (Cam S., op elman, 1991, S., ASP) 13, h h ottom, ort Planetary 94, 94, 457 S. K. t: t: Kastner, ez in A&AS, & & 275, C. eds. eds. 15 Conlon, 274, eim Reidel), Reidel), 1 2000, Planetary (San bridge: , ASP Bro Ph Hollo Ph L., ApJ, A. S., J. , Los I b R. R. W. 445 I: ysics 83 ysics C. ert, 961 wn, Cheongiu, A. 1996, & Hyung, F F Conf. P 147, w eds. Viotti, Viotti, Angeles, N. rom rancisco: Nebulae, A. ASP 368, A., a E. Ap&SS, Ap&SS, 2000, Lutz, CUP) S. P y of of , Sok . 1990, 1995, 111 J. S., A. Neb- J. MN- Bell, , Ori- F F Ser. 486 97, or- or- 99 er, A. A. H. E. S. J. & in J.