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1989 Sanduleak's (LMC Anonymous): Its Similarity in the Far-Ultraviolet with the Luminous Object and Sn 1987A A. G. Michalitsianos NASA, Goddard Space Flight Center

Menas Kafatos Chapman University, [email protected]

S. N. Shore University of Pisa

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Recommended Citation Michalitsianos, A.G., Kafatos, M. Shore, S.N. (1989) Sanduleak's Star (LMC Anonymous): Its Similarity in the Far-Ultraviolet with the Luminous Object n Carinae and Sn 1987A, Astrophysical Journal, 341: 367-3. doi: 10.1086/167500

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Comments This article was originally published in Astrophysical Journal, volume 341, in 1989. DOI: 10.1086/167500

Copyright IOP Publishing

This article is available at Chapman University Digital Commons: http://digitalcommons.chapman.edu/scs_articles/109 1989ApJ...341..367M sianos excitatiOn optical is type fea~ure. cosmic LMC mcorrectly revealed ~ecently, because stages Cloud at Important mixing, A.A.1239, SWP One 1984). ~ Ultraviolet THE © ted 1989. The untypical The 1 cx(1950.0) Guest AsTROPHYSICAL M object with The Anonymous However, 1200-2000 et departure and of first spectrum giant. abundances American at and 1243, the spectra are during little al. Anonymous, Anonymous material, hnes mdicate Subject ~ous ~IU_E) be of observed LMC Investigator: stellar symbiOtic © the included Spectra clues is 683~ SANDULEAK'S 1982). which = the Explorer considerably low presence of extreme. the American known Furthermore, was Astronomical compared 05h46"'02':6, N surface and A~onymous symbiotic of the presence in JoURNAL, evolution headings: dispersion from of concerning history IV] provides the ~· A known the exhibits which in is spite International obtained the the helium among was spectra stars which demonstrably as A.1487, presen~e of closely (IUE) SN This normal peculiar which Society. I. composition S the Sanduleak's S-Condensation of 341:367-371, INTRODUCTION with discovered of was of smaller <:ondensation stars of that 1987 no stars: ultraviolet: significant «5(1950.0) the in Astronomical All shell symbiotic high-excitation could the (limiting this IS nucleosynthesis is and WITH an obtained indicates in resembles the of rights intermediate STAR solar evidence formed Ultraviolet the a presence of emission A far-UV generally show in NASA object. the field burning stage. unidentified abundances- LMC reserved. N Astrophysics circumstellar-high-excitation properties than indicate suggest reduced general cosmic not 1989 of m] far = Star in THE (LMC resolution [Fe star departures Goddard stars when spectra Printed emission-line evolved departures -71 with LMC symbiotic, Explorer whatsoever the June the of that Anonymous UV A.A-1749-1754, object is and (LMC only vn] whose the (see, that abundances found emission LUMINOUS strength strong apparent and °17'13". in massive-luminous Large 1 Research wavelength the during the ANONYMOUS): of of U.S.A. Department Society Anonymous Space Received SN broad A.6830 emission seen the stars e.g., carbon LMC These massive envelope-core Anonymous), of stars: progenitor International from nebular in because 1987 Flight from evidence Magellanic Center, AA. for Until S the LMC, of lines, advanced Michalit­ spectrum emission, from A. 1988 emission in provides in Condensation Anonymous, points but normal emission A = C associ­ of a envelope (Allen Center, G. normal • high­ stars. range Physics, May 1982 late­ 6 line-forming very may IV New was N v N OBJECT M. ABSTRACT the the the S. MICHALITSIANOS A) Provided was for or N. are 9; KAFATOS Mexico Laboratory galactic 367 absolute AND provide 1200-2000 accepted gas, C ITS George line- cosmic SHORE circumstellar in discussed burning III] (1983) (1983) was similar sponds an crepancy its lines Allen nic UV be pletely presence present E(B- sion C optical accurately osity [0 the the normal resonance or which the Institute rt of SIMILARITY Lack III] optical explained emission. Mason 1988 II], 1 independent Sanduleak's He Cloud CARINAE region object third continuum rt important for too stars: intensity lines by high abundances 0 of (1980), V) Carinae. A.A.1907, adopt [S have Astronomy II and absent. to November A and is IV] cosmic in in of to weak of LMC 1 line the University of = between n], strongest Mining that spectrum rich with the mass-loss (Shore, lines detail. supergiants- because LMC can rt photometric an emission A.A-1401-1407 four 1.2. dredge-up UV noted the if ratio, [S The Carinae, the NASA luminous to of include: in Anonymous, the 1909, At E(B- not clues the abundances, The in 3 As m], AND C Star and and ionization Balmer spectrum detect estimate the Anonymous, extinction IN CNO of the narrow-low IV Sanduleak, optical the optical which of discussed that be International emission (see, Technology He Solar similarity nitrogen phase N which A.A.1548, THE V) concerning in that He uncertainties LWR/LWP resolved, SN the Astrophysics have I, the [N v, blue processed the emission estimates - e.g., Physics variability II Fe and is stars: wavelengths, depth of N is 0.3 far-UV and of 1987A stages A.2200 II], I(A.1640)/I(A.4686)- as FAR-ULTRAVIOLET are E(B- VII, Large however, are Kafatos occurred object after IV], by rich 1550 E(B- LMC 0 and relative but between a (Av velocity [Ne Balmer and generally and supernovae­ III] conspicuously Kafatos in red the lines Ultraviolet and absorption of V) in material. of Hex Allen 2000-3200 are and spectrum = of Magellanic the III], makes S18 V). the A.A.1660, Anonymous nitrogen. whose et supergiant. = extinction 1 nature extinction. CNO-processed is N and indicate to simultaneously weak. line hydrogen intercombination al. [N 0.3, emission LMC mag). However, Balmer [Ne in Data difficult 1987), m] et carbon strong 1983). the ratio II] [0 LMC mass which al. Although 1666 v], emission Explorer of of feature Numerous A The Anony­ A.6584 However, Small Cloud, (1983), m] A.= System but weak, lines 1.3; LMC LMC [0 method range based Kafatos lines to IUE lines indicates in may that Anonymous may is Blair intersystem A.5007. the I], this determine objects dominate 4 to obtain based produces Magella­ or is mag, the of [0 also on lumin­ corre­ could large. et emis­ com­ from et lines IUE The dis­ III], the the on al. al. be or of 1989ApJ...341..367M for entrance exposure) lines longest minutes with able contains length genitors, These the trum the tinuum where while were supergiant stationary fected. core-envelope and circumstellar associated and a analysis emission, greater greater The galactic 2200 Kirshner where toward which nitrogen mous, narrow sation, spectrum supergiant. 1 and LMC, the Anonymous the reddened ratios processing Si Fransson 368 ,.., -400--600, were factor 57 Low-resolution Although Similarly, III], massive LMC LMC permitted nitrogen symbiotics. N absolute C at lower ofN DN (LWR A obtained C points which suggest NfC,.., obtained and characterizes a range and This 111] III] exposure the peculiar provides than feature emission-line just than III] 3-7 object difficult. exposure) lower in and above 1978). material by its aperture of et v, Anonymous of from flocculi © with limits and of Hen, emission, Regional LMC progenitor, may is object N greater al. which 14428; may circumstellar LMC the far-UV are normal the exceeds includes LMC above were overabundance material, which American with intensity normal SN 8.8 line not reddening, mixing, IV], 17 986 limit 1989), core-envelope the may As background. using other The ultraviolet discussed S Carinae be indicated (SWP strong strength and ± Anonymous, have IU 1987A in 17 Condensation obtained estimates and Hen, of such, associated Anonymous that massive Anonymous. on is present 120 days than 4 background. Carinae, spectrum the systematic values. of be E Cas Data normal provides N the where the spectrum (Fransson systems cosmic the II. significantly for and spectra of bearing 1985 1982 18315) N/C,.., minutes) when unreliable v, is evidence IUE the extremely 0 normal (see, are software intersystem OBSERVATIONS apart, A, while emission dust, absence in of both for extinction, Analysis compared Astronomical III], rich (,..,100M but a Other exclusively the show greater of July Absolute was distinguishes believed with cosmic nitrogen October high e.g., SWP abundances. with mixing C is SK in that theN compared compelling N which NfC 50, just effect epochs of the on is prominent and in similar IV. An et cosmic revealed the has expelled III], 1 The that data nitrogen an Davidson of respect SN related for rate or lines -69°202 LMC (SWP The indicate al. extended far-UV CNO-processed above greater spectra detail. Facility in LWR SWP both d values v C lines been may isolated and makes in in with formed a line large peculiar 1989), 1987A lines SWP MICHALITSIANOS, analysis ejecta line the 10 are in IV luminous of fluxes to factor values which of this with Anonymous, weak from only 26327; ofN objects, intensities and the background. indicate to Sanduleak's 1200-2000 show (SWP compared 2000-3200 the mass evidence S lines relative N overabundance was shown Recently, is overabundance of by CNO than in at a et object. Condensation Society or LORES was carbon nebular from (Kirshner v, seemingly in field straightforward large shown supernova S the the C (Chevalier a of al. IV], the NASA-GSFC. routines a emission LMC C ,.., ofN a condensation N loss photoexcited the trace III] 425 (,.., large at IV 18315; SN 1982, factor 197 Balmer undergoing such in processing. S a 20 weak star IV], N 17 10" However, for emission, 10 least obtained tendency material, emission Conden­ emission v, as in of Table A with minutes Carinae the III], M A or Anony­ DN, spectra of 1987A, 6 Star factor, if N In N as wave­ in Table · avail­ 1986). LMC x CNO 0 1988; a 6 • spec­ unaf­ stars con­ -35 C pro­ n H it , and L and line 295 UV 200 IV], III], 20" red the the the the B3 by or of in 0 Provided of IV 1, is ) KAFATOS, (Kafatos are absolute decrement He measure kpc. which Anonymous stantial sidered free-bound far-UV achieved corrected detected optically ingly, The December. We Anonymous the mous region . S smoothed excitation of as quite Mathews the that variability tively however, prominence SWP spectra, 1986), 1987A 1) spectral .U487 ,.., N1v] N N C C Hen21640 SANDULEAK'S Condensation In We 5-10. • b III] IV appears v III] E(B- well, uncertainties (x expected Indicates n estimate object 221239, 21548, Limits optical are by ).).1907, .1.1487 2.1.1750 Spectral establish Figure active. the 10- A.1640 are 1200-2000 is can resolution and and (top in flux by The and AND reddening. magnitude et in mv,.., the V) if 13 -40-50 is i.e., flux (1969) thick spectrum 1550 conditions not ...... spectra 1243 is in the appear real, ...... emission. al. An Pengelly estimate is we strong with N ergs the ...... 1909 distribution on = large. by panel) Line depth of optical STAR the to to that too (bottom The the NASA probably 1983; 1, variation 111] 0.2, corrected ;:::; ...... adopt extinction 16 variability SHORE A.l. LMC ...... interstellar far-ultraviolet first cm- the be but ...... to He and 10 in presence variability the in steep low-resolution (LMC He A = the (Sanduleak DN A.A.1749-1750 emission We using of 9 J(A.1640)/J(A.4686) extinction. in the 2 (Fransson essentially nitrogen • considering 6 17 of is Allen further n depth ...... The range (1964) the s- have background of n A. an the Accordingly, photometric Carinae of panel) Hix A.4686 not Mv,.., Astrophysics for above Anonymous): 1 . have .U640 III. T Lyman ); inC quite with for SWP intermediate the properties correction offactors Fitzpatrick surrounding fluxes in S of 1980). ,.., found either in ol then would feasible extinction TABLE was DISCUSSION to Absolute observations Condensation extinction. lines this 10 N v N IV dereddening intercombination is Lycx 18315 used ratio wavelength - line background is 1977), be heavily et (middle 5 not 3.7, ;:50.1 between quite its constant. Balmer are compared From probably line. K. of that 0.6 0.3 2.3 far-UV 1.0 1.0 -2-3 A.A.1238, reliable, is of al. subtracted 1 (10/17 indicates UV corrected accuracy apparent with Flux• h formulae the and for the determining expected characteristic of was which N ,.., Similarly, can 1989) (1986). weak, reasonable value LINES (see the reddened. panel) an /82) 7 be the The two v, the Data the 1982 lines applied (Kafatos are is text). 1240 be spectrum LMC He due law unless appreciable, N for is and OBSERVED Weak corresponds difficult to hot the cases obtained of Balmer present continuum for visual so derived required (Davidson to spectrum SWP 11 The and -25%. IV], extinction; if for to E(B- spectra a indicates System could Absolute line lines object an LMC emission star distance= be to the suggestion there agreement free-free an The of A 26327 1985 et the and of magnitude, three-point continuum ;:50.1 extinction­ quite ratios because SN WITII or data. line Cox of 0.6 0.8b 0.4 2.3 1.1 al. of from in V) emission all accurate Accord­ Vol. in also to Anony­ may 30 Balmer Flux• (7 is B N (Table of limiting 1987A i.e., of in N ,.., 1983), LMC LMC to /1/85) IUE et high­ three large posi­ ratio 1987 lines con­ sub­ Dor that The and and 111], 0.9. SN the the 341 the IV] an 55 al. be be of of of is 1989ApJ...341..367M material. extinction (Davidson of '!-Carinae. evident. imply on Carinae camera emission contributions in intensities values the narrow-low resolution mous parameter. but present, sible emission Point 1909 No.1, Because FIG. 1987 time properties o.:C LMC the 6 are ~ b, ..J ::::> "'" >< LL ..J ::::> >< LL E u Cl Q; (Sanduleak's presence of Source the scales 1.-Top: together An obtained December. of The not 1989 lines extinction 0.4 0.2 0.5 ofN SN 2.0 spectrum Weak 3.0 1.0 0.5 values 1.0 et within E(B- is velocity absorption presence 0 0 evident, © 1200 spectrum of from a/. Note of 1987 consisting small, v, American these at of C ~ 1986). with survey by N)Z I I of N N)Z IUE of V) I A several IV Star) least )l a The IV], emission obtained LMC estimated Davidson dust = that obtained further Fitzpatrick ).).1548, 1" He E(B- has low-resolution 0.2 Prominent uncertainties, of Hen, 3 spectrum by of radius SiN 1400 11, failed B yr. not the has will in circumstellar SANDULEAK'S N stars Kafatos Anonymous indicating I Si LMC spectrum The 1550 on been V) and by WAVELENGTH v, been et IV], the component for NN] N be NN] (1986). Astronomical in 1985 a/. Fransson N to of - intersystem I I emission N N] I is emission corrected and SN the the discussed CN applied ANONYMOUS direction (1986). IV], 0'?05, et LMC III] detect an spectrum 1 July a associated 1600 aperture a/. Si S depletion Middle: are similar average He 1987A we HeTI Heii III] (1983). Condensation et Heii The is 1 so to dust. by 1 lines Anonymous, n, for I lo:mJ have 0 (SWP any emission present, a/. I of are I the 0 SANDULEAK'S that in :mJ spectrum reddening. further have STAR varying (1988), of extinction of with The Nm] The Nlill of prominent. m], of spectrum the measurable However, (.A) to determined I 26732) exposures LMC 1800 N carbon been substantially which circumstellar the N S-Condensation SWP relative lines ] Society representative v, m], in is S-condensation is removed. N E(B- of Si of not may using in .U1200-2000 the Anonymous but IV], E(B- and Bottom: I LMC intrinsic ill] C emission in circumstellar dereddened, the m] be text. which 2000 the N infrared C the a V) material V) variable Narrow ).).1970, Anony­ III] III] IRAS range • large STAR, of LMC as Low­ pos­ = of We line are are the the 0.6 Provided to in A a 'I '7 supergiant; M emission amount like it mv- Mboi- the Anonymous Anonymous, than high responds ticularly yield unity. peratures for CAR, extinction of E(B- from found (Kafatos lower ate emission emission emitting effective could genitor density can osity izing is 15 40,000 tionary Zanstra value that where perature bidden E(B- E(B- and can obtain HfJ the the however, peratures. photoionizations S18/SMC 1242 - as boi The The 6.9, T.rr· Mbo M LMC to bolometric spectral A.4861 estimate number also M a bright by LMC - value a an 0 density requires is source, 13.5 to V)- which V) V); However, the 1 limits AND only mass UV boi explain range Wolf-Rayet IH K. was -6.0 -7.8, a - lines. ne tracks evolutionary temperature. of consistent 07 the is temperature the the measure region be Anonymous of et to we feature bands is we assumed. lower However, LMC. is -6.8, (Shore can E(B- (Kafatos (Shore In emission than T. dust of Anonymous as, 0.9. it a in type obtained lower star, has also is a great al. bolometric and the can the when of of SN and NASA sensitive find B3 - is We any E(B- say when a say, relevant be appreciably rather magnitude high-excitation this Truran stellar possible 10 is photoionizations (Kafatos the 1983; a rather while V) Zanstra are For supergiant limit ionization of estimate its et per those a estimated 1987A therefore at n: et - of assume that corrected than strength case, 4 likely the compared with star. <; the strong et al. line presence 6.8, V) K, E, this large it magnitude al. Furthermore, 6830 a present, second, <; of from luminous track 1. Astrophysics luminous al. line parameters the to evolves Seaton 20 to 1987). appropriate would T.rr which 15 high star. 10 and 1987). the is intensities the respectively. My lower For that a appropriate present However, temperature et 1983; SN 5 increases M a the A in M a disparant star greater giant ratios function N the are -120,000 K. (Rousseau from star lower unusual potential on V al. Weiss ;5 The 0 hot effective 0 comparison, in of where The the all is 1987A to v, could imply , photoionizing If limit magnitude star, symbiotic 1960), off He A -5.4, is unless not strong 1983). proportional Seaton increases supergiant and LMC blue is argues the in star cases LMC or values LMC the in on similar presence per than shown limit can the not 1 (1988) for is the to radiative with the is L in the A.5876 even theoretical of for then strength also The off which object ratios range whose the temperature obtained, K. from which E(B- sensitive for is The Mboi- for et unit photoionization. be UV disagreement main strongly Anonymous, that the envelope, bolometric magnitude Anonymous are Anonymous absorption, 1960) Data Anonymous of for shown metalicities far-UV. the al. A E(B- the stars main in luminosity by used of problem that a the hydrogen. reflect have T.rr. My line to emission of an in the much lower of corresponds time, S 1978), the of Table pathlength V) my supergiant estimated sequence. aBC indicates to main ratio, flux the of 18-SMC, HfJ SN transfer -9.5. the the System to a when and to estimated is He in emission, sequence, V)- effective the early-type tracks, shown and dependent - nebular The N considerable greater estimate high similar unidentified higher N;, the Table limit A.4861 1987 with optical 13, LMC. of L; 2 II ;5 number is determine v where sequence, appropri­ especially from This is indicates measure, which A.4686 with of 1, A [Fe 3.7, = the electron value making A.A.1238, we seen A lumin­ earlier would T.rr- values My­ evolu­ effects of For where of LMC From IHN;, LMC lower if more to 2 ratio than tem­ tem­ tem­ pro­ par­ here to cor­ ion­ The and and for­ VII] My can are T.rr the the the the 369 the on an to in of of B is a '7 1989ApJ...341..367M stellar (Davidson combination giant has bidden estimated processing, pre-main-sequence gaseous was the bursts significant (Kirshner cated Thus, the material probably 1982, impacting 202 material with resulting of 1978). mous (1983). forming could Condensation oxygen, Fransson N -100M Carinae, 1987 giants. rected N E(B- Carinae, - 370 In The 69° In III], the original25 a IV] should significantly S A terms wind LMC or SN 1986). in the 202 still V)- region resembles from S lines as In On Condensation spectrum (Fig. N/C regions supergiant. features lines, in IUE the 0 in Condensation underwent which and composition of terms et to evident 1987A. intense was , 1988). et mass be ©American rich the of a where reflect the 1 Anonymous, The SN of blue the supernova al. al. = lines circumstellar 1, be 0.3 0.9 1.3 would tend would during quite the SWP E(B- in to in M [0 • • • • • ' b other 8.8 in a 1986). top ...... (1989) are loss Estimated Spectral of M Assumed Nebular surface Estimated L Lis 1987 is massive nitrogen '7 A overabundant the 0 nitrogen many which that CNO [E(B- the core-envelope of The in is object III] substantial = the ± Carinae UV luminous, star heavily V)" the similar star, not panel), the P 12()(}-2000 phase, a N a hand, high A 10 4 the N/C and . . . size relative phase indicates in high Cygni mass of type temperature source III], 7 was significantly affected significantly remnant is and values-best products, of radiation of from from were circumstellar of but L V) to 03 low-resolution the of to the mass-loss in line the explained [N region, 120,000 120,000 120,000 0 corresponding Astronomical is if (Fig. of the '7 the as process core N the lost mass-loss increase = carbon B3 the of the N/0 (Mboi- is LMC the supergiant, at Carinae low-velocity line while advanced relative II] IV] strengths strengths 0.3] nebula. expelled emission-line well surface of correction extreme high emission A probably He (Lamb in least photoionized 1, mixing Cas reddened, strong supergiant in assumed, in which which profile value = photoionized spectrum n/HP middle 14 photoionizes Anonymous as may the shown the phase emission-line (K) mass 10 10 104 the v N r• N 1.5 by A, e -50. -12.5) phase, 4 4 material is strengths composition to is the measure 1978). ratio MICHALITSIANOS, extended relative optical during relative of prior ± UV, evolved where 0.9 the has was lower evidence SWP stages the have one and whose structure an panel). loss, as material 0.8 the n.(cm- region. spectrum (see (see '7 of by the density by formed supernova of spectrum formed perhaps a progenitor. and Society evolved (Davidson Carinae At 10 10 10 limit N of and to N text). also text). indicate was until red extinction from 7 7 7 absorption Kafatos the absorption. to LMC repeated central to IV] is the end luminosity of 3 a core-collapse A nitrogen-rich of emission v, LMC is )• low-velocity nebular of then strengths carbon more 12 supergiant. for a number lower in progenitor been N of associated T.w the relative found evolution a lower SK -40% C when of as is massive circum­ is the III], n;E(cm- the Anony­ 4.2 5.1 (Lamb CNO­ n. of it super­ object shock inter­ ofthe not a the like -69° et • STELLAR et limit 1064 indi­ limit out­ ~ also X X star for­ cor­ The UV and and line red SK SN al. by 10 10 10 al. Provided of of of to of is a S '7 TABLE (see 60 62 7 3 KAFATOS, em- ) PARAMETERS text). 3 4.7 factors difficult resulting SN smaller larger, obtained lower 3.7 LMC Kafatos 1.6 N/C- (Stahl1988). 10,000 consistent cosmic indicate indicate Thus, if Davidson mous the moderately E(B- E(B- a emission circumstellar dust in LMC reasonable ratios could LMC LMC, the we the wind, rate nebular phase, and asymmetry He 1987) (Kafatos 2 any few Compared L(cm)• x X X the find II circumstellar discrepancy S 1987A, optical 10 10 10 by of could J(A.1640)/J(A.4686) could if LMC Anonymous, limit, that Anonymous Anonymous V)- V) indicate where 16 16 15 and extinction heavily luminous IRAS Condensation, K, where 4()(}-600 values et 150 N/C mass most material that AND to et em absorption the significant - at al. in by respectively. et with imply comparable have mass-loss al. and 0.3, 1983). 1.3 reconcile which be the Anonymous emission sensitive and a I:- al. Moreover, ratio the Davidson Vwind Point of NASA dust loss vesc with of nitrogen 4.2 2.1 1983). rather 1.8 (Kafatos reddened mass SHORE N/0- M(M (1986) position the an and that apparent nitrogen anomalous blue was N/C an observed 30,000 shell from - x x x would extends of - can was indicates average the 10-' 10- Source 10- the photoionized E(B- 2000 0 absorption based outflow. 30 corresponds )• M- supplied diffuse, We from lines rate with stars to in for assumed Astrophysics 4 2 is If to not the a 70 range a SN overabundance et ratio et km K could of the symbiotic the very be red I: relative dust km emphasize our of from for al. V) which is the nebular 7 x 7 al. Catalog. that photoionization on LMC 2200 <: <;60,000 be <;35,000 (Fransson the of mass-loss 1987 obtained, s- absorption M- extreme not and giant 13,000 T,,/ S (K) - electron 1983), s If which E(B- estimates of during shell (1986) extended. blue immediately - escape LMC the \ 10- Condensation that 1. the are the 1 Balmer based A abundances A evident, • to of which nebula Anonymous they However, to On w-s or 4 2200 mass surrounding wings absorption suggests and IRAS He carbon order extinction stars V) However, I:- M yields that Anonymous I: the should departures detection supergiant, Spectral although the rate temperatures et = 0 upon found for II - M Data properties. relative lasted A Evidence B7111-II the lines implies was hot 0.3. although yr-1, lines with 13,500--16,000 a of 07 al. dust the 03 other 20,000 0 LMC absorption of an and few imse because dismissed they v models that yr- the I S star Type• created be These 1989), N/C the N/C- w-s N/C- could is is the which E(B- which System sources feature. dust in - Condensation, if oxygen, this LMC 1 nitrogen hand, to not considered a from indicate circumstellar based Anonymous. evolutionary would K 10 the (Shore is Balmer most for - presence rather line Moreover, carbon results 6 M and greater, while would (see, (D-types) assumed. indicated be in 1()(}-150, V)- infrared. yr 50 yield Vol. 50. indicate infrared 0 Anony­ normal a feature do in on profile a In of where much imply K when yr- more ratio I: et little slow lines high size, e.g., For line not 0.9, are the for the 341 the for be an al. - of of 1 a a . 1989ApJ...341..367M NM --. A. S. MD M. Chevalier, Cox, Iben, Davidson, Fitzpatrick, Kafatos, Davidson, Aller, IRAS Fransson, Blair, star stars drawn J(A.4686) rt for luminosity Allen, because sponds factor licities if violet this giant Z LMC by core librium. Alternatively, librium. taneously Anonymous and intermediate-mass No.1, carbon cates overabundance in Aller N C values parison, N/C Precise ~ (Washington, 95. 27S,584. Kirshner, 867. Ap. Carinae the N. G. Low-resolution = The III] 100, KAFATOS: III], the factors D.P., CNO-processed E., process. with L. W. J. 0.02, dredge-up D. oxygen MICHALITSIANos: Point SHORE: depends has branch et dredge 87801 20771 Anonymous 1984, spectra a of Suppl., Jr., H., Ross, H., to M., Michalitsianos, A.A.1906, N assumed IUE consistent A. (Aller 1989 P., strong to is R. al. K., K., values of and C., nitrogen line the - and T.rr K. the IV], R. 1980, been while Stencel, an A., © extremely Source Pub. (Ulrich evolving of Walborn, 1981). Dufour, uncertainties 500, P., C. of 53, Cassatella, Mathews, DC: SWP Renzini, and high stellar Department can = Department 07 up suggests and American et ratios in 1986, Ap. and J. ~50, critically of Astr. 573. overabundance IV. for suggested LMC and 1909 120,000 in E., depending (see, Kirshner, is al. US R. is V LMC the Letters, Catalog. produce Sonneborn, Accordingly, with N excitation R. overabundance the O'Mara, AJ., A.A-1200-2000 SUMMARY (Sanduleak's correspondingly Soc. IU N. F., also and star, abundances GPO). 1981), A. surface and C-N J., W. v; stars indicate quasi-homogeneously, e.g., nebular weak are R., emission Feibelman, A., E helium-burning 1984, 92, Walborn, Australia, our Anonymous A. large G. that C Laboratory Anonymous 20, on and occurring. K. Scalo or R. the SWP in G., envelope 1985, Gilmozzi, IV 1068. 1969, lben comparable of B. large to even of 131. Phys. P. estimates E(B- for on Convective Astronomical of G. reflects Gull, or extinction, Allen, in J., CNO Physics, 1978, planetary product values AND Physics, result an 1989, in Ap. and the fact Joint the completely S, N. and we 1972). W. Repts., spectra 2-8 of variations though line-forming T. are Star) 369. range D. the J., E(B- Ap. R., V) Keyes, initial CONCLUSIONS R. P., case suspect Ap. R., nitrogen burning is of Abundance the cycle for A., Renzini ISS, M IRAS of in and very difficult and J., 1982, for is may and the George lOS, vicinity J., indicates of Panagia, Astrophysics and 0 Evolutionary region ~ N/C in 219,931. Astronomy nuclear a mixing E(B- nebula SANDULEAK'S in 859. but C. , V) Gull, of difficult 336, C LMC Michalitsianos, mass strongest 10 13 331. 1',. Ap. massive large, is Science Stencel, emission D. provide NGC with that in IV absent, CxN = the has 429. the could 1984). J. over relative T. in However, 1981, to the so 0.9, Mason A.A.1548, of V) Society (Letters), of region and Anonymous. N., R. in NGC in processes strong occurred peculiar complete ratios He i.e., obtain the can R. = Working low-metalicity C/0 6302 that 1986, M.N.R.A.S., to the 0 objects which normal Wansteker, indicate star emission evidence initial These E. the and 1.3, II strength asymptotic and by Research University, determine tracks to 1983, vary 6302 star. A. 254, Ap. J(A.1640)/ and 1550 of can evidence (see, material for nitrogen such an a Solar because G. carbon B simul­ corre­ object J., of Group meta­ where factor ultra­ L47. LMC • Ap. equi­ STAR, com­ N/0 03 solar by vary 1983, type indi­ The that REFERENCES 305, 197, e.g., and the line for for A., J., as Provided to Physics, a I Center, Fairfax, rt Ulrich, Shore, Sanduleak, Stahl, Truran, Seaton, Rousseau, Lamb, Maeder, Pengelly, Kirshner, Michalitsianos, at will temporal N convective further CAR, ed. ground-based object Hubble Program could of important indicate mixing. relative because primarily IUE envelope evidence envelope down with the carbon an cosmic observations, over velocity region neously, with UV core University Cloud, {Cambridge: Val Large Ap. Code 1978, New This NASA C intermediate IV] increase Nitrogen prominent VA lines J., 0. Morin, IV by S. be the S. either R. this (Maeder M. Astr. observations J. to and in reflect A. AND N., 253, A. ed. Mexico 1988, R. work 684.1, A.A.1548, Magellanic K., was R. W., of from If J., abundances we J.1960, Space that to N. circumstellar 1987, the required present greater the for when 1978, Goddard M. in and of nature material, 22030 Press), P. burning Ap. M. variability and Martin, period 735. Quebec, the N information and the motion 1977, by the would in carbon, Cambridge being processed 1964, N the A. 1988, He-shell variability Allen, was Kafatos Suppl., Astr. dredge-up the SN III] NASA NASA Scalo, Ap. would Proc. the variability and Weiss, G., at Rept. v asymptotic Institute result Telescope emission LMC S I 1987). p. mass; 1550 Laboratory '!f. detail. M.N.R.A.S~ J., IUE and of in N., least time Kafatos, to supported Canada, Ap., Cloud, Condensation 313. (Table 1987A D. core, have IAU Bull 31, to spaceborne J. deep 220, Proc. Space Progr. during emission although A. Prevot, of also and A. M. because Goddard remain fluxes of in 173,287. University N burning 243. data Anonymous 1988, 60% further C V of scale region Astrophysics 1987, The 186. Colloq. 1972, at LMC concerning carbon ar. 4th IV] expected ed. A. N/C occurs whereas in of IV 1988 M., Phys., vary of lines 2); Flight ionization the E., Stars, will G. 127, in Workshop the base. Astr. core line between Mining obtained have giant M. Ap. Feibelman, the extreme into for under for August fairly Supernova lines Rebeirot, N 113, - Michalitsianos this the 23,313. of 30% surface, Press), accordingly. 145. Space Anonymous, of investigate stellar observations J. be No. over Ap., emission Kafatos intensity convective carbon 150 Astronomy III] Center. of The nitrogen. SN (Letters), dredge-up remained Physics the carbon N branch, CNO will of the required 1304. level. 15-18, constant 176, rt was and p. in the and 1982 and v, the 1987 A., this Carinae, Flight nearly intercombination constant departures W. 1987 changes interiors 87. Astrophysics, where IUE 59. be and N emission-line of relevant Robin, in A~ Technology, Data entire 176, in If is products variations He A N/0 extremely to A, Luminous is {Cambridge: difficult IV], press. confirmed where and essentially the this confirmed in mixing More Guest A. Center, L37. 3 and 1985. to occurred with may and more carbon it the II A., yr or Hobbs, flux and - envelope of G. in helium-burning System investigate A.1640 could Large point. and apart time Solar SN from 70 with more evolved IUE observations indicate The Blue most Investigator Michalitsianos the to of are observed affected N Greenbelt, can interesting 1987A Brunet, is compared R. Cambridge Magellanic strengths by Socorro, core establish in scales constant Variables, stronger m] the simulta­ produc­ indicate indicate and Physics provide W. nebula, formed lines normal intense Future not depth, of future future in stars 1982, low­ may J. that and 371 the the the the by be P. of of in