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1989 : Evidence for a Two-Sided Radio Jet and a Circumbinary SiO Maser Menas Kafatos Chapman University, [email protected]

J. M. Hollis Blue Bay Res Inc

F. Yusef-Zadeh Northwestern University

A. G. Michalitsianos NASA, Goddard Space Flight Center

M. Elitzur University of Kentucky

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Recommended Citation Kafatos, M., Hollis, J.M., Yusef-Zadeh, F., Michalitsianos, A.G., Elitzur, M. (1989) R Aquarii: Evidence for a Two-Sided radio Jet and a Circumbinary SiO Maser, The Astrophysical Journal, 346:991-996. doi: 10.1086/168081

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Comments This article was originally published in Astrophysical Journal, volume 346, in 1989. DOI: 10.1086/168081

Copyright IOP Publishing

This article is available at Chapman University Digital Commons: http://digitalcommons.chapman.edu/scs_articles/110 1989ApJ...346..991K means Aquarii, make radio NE; applied to toward been (250 symbiotic from and in imity, voluminous, type Aquarii, periastron, prised THE © 1989. In 2 1 One both the On National ASTROPHYSICAL references pc, in symbiotic 1980 the some The counterpart. a is NE leave of (Herbig of directions 1982 the to sensitive according American Astronomical with (VLA). from explam maser-emitting Subject mase~ structure, found detected the vanable tiOn ~iscrete phenomena often cool but a the the a © radio from Research Vfe forming SW question hot brilliant Sopka central red American a star the between R most system, therein). the observed Northwestern have location 387 SW has system 1980) subdwarf R Aquarii In headings: JOURNAL, measurement the structure, giant radio parallel 14.94 is R to existence The Council AQUARII: binary the the eluded day et interesting an radto captured morphology H jet detect~? as Aquaru Whitelock in emanating and al. I. star Society. radio/optical accretion These II spectral (see 2 ~ontext knots GHz to period. of NE and are 346:991-996, the INTRODUCTION region (1982) Resident region. to and companion the structure system University. masers- stars: detection. material Astronomical we whether whose All Michalitsianos the described radio/optical of circumbinary analyzed systems (- rights by by collimate? closest NE combined for 6 classes It EVIDENCE of disk a 1987) detected index Laboratory is 2 the Research disk radio em The reserved. combm~ng from and is light detecting whose of a definitive em) far Space 1989 the was believed jet suggests hot previously_ axis. one Indeed, for the nebulae: are which which, by amorphous in kinematics gradient removed of as in Printed continuum radiation R varies, extends Department November term Associate. star discovered Data the ~.86 all orbit to binary suspected central F. nearly for context a orbital Aquarii features. nebulosity. and in prototypical Earth a can of YUSEF-ZADEH Astronomy predominantly that optical and radio Society data U.S.A. Department there Received btpolar "jet" FOR SW GHz in around H the virtue -10" reported of from Computing Kafatos eject objects 15 the - all object. material II semimajor of of of is counterpart morphology toward the emission corresponding 6 In has to (- counterjet regions- by should A Physics R jet's stars: the of em a case 1988 NE material symmetry, and order the of be Aquarii 6 TWO-SIDED thick NE optical always a of The the R • is prox­ radio em) Further, com­ November dust­ 6 cool, northeast Solar 1988 Physics, of of Division, 1 system's SiO and lost symbiotic J. the ABSTRACT Aquarii em the • M. M. jet 2 be Provided to at R radio at R accretion implications M. radio AND axis Astronomy, Physics, KAFATOS 991 ELITZUR stars: structure, AND the MASER of George HOLLIS extending 7; NASA/Goddard we A. is to features the SiO continuum radio/optical accepted (NE) Mira might system; amorphous cal giant, well with with suggest system struct amorphous at detection of data resolutions to As vides radiation uum SW -0':5, NASA/Goddard circumstellar G. -17 have different We Our several RADIO the Mason the new disk such, or University maser by of be MICHALITSIANOS the acquired 6 counterpart the and envelope further the binary also concerning be typical creating 1989 plane AU. efforts R bipolar em due determined that that found collimated to model the moreover, combined University Aquarii, the associated of array less pressure, collimated the position May distances jet emission were Space configurations morphology JET to ~ a This radio the the of jet. NASA of orbit extended of with SW were evidence 2 structure, 2" Kentucky Space amorphous, a shells- in 17 that jet and configurations. turbulent disk, bipolar accretion Flight the motivated em geometrically AND constructed provides jet R to and continuum the data phenomenon the (Kafatos, expells SW Hollis rewarded the Flight which has A-configuration. may emission southwest with of Aquarii. flow provides SiO Center primarily Astrophysics VLA is newly radio set Mira A structure appearance stars: -2500 for been of the Center best well SiO disk on motions, maser is et CIRCUMBINARY material the at of further to collimated since collimated orientation located Michalitsianos, from al. the by the spectral atmosphere previously detected component seen the search structure, individual strong Additionally, less maser be is thick (SW) AU at the (1986) when inclined highest side emission 1982, is due Very intense the periastron in evidence in of which distinct on detection accretion of Such -250 for emission evidence of radio combined index the to both by Data NE interpreted bipolar the had either mass the Large of possible which 6 a proposed (R local relative SW radio using at could small-scale by might the AU symbiotic jet maps directions disk Aqr)­ from previously we distribu­ and em that the passage. jet System of making for outflow side disk detected shock Array newly extends structure. 6 structure away data radio have data counterpart. facing a partially Hollis resolution SiO to a with the the em explain collimated, to of in which, symmetri­ the obtained set. features context normal contin­ It images spatial in the in deter- 1986). plane -10'' This may pro­ We ob­ the the the via M of 1989ApJ...346..991K Universities, Foundation. configuration, comparable emission continuum the mined position spots, 992 central context are employed discussed 2 VLA taken Although reported were beginning between SiO separated session obtained described diate Hollis Mira was source em enhancement calibration observations The 48 minimize tively. Aquarii pairs. 1950.0 We the of 0-configurations are Fourier-transformed which - -15°33'42':890, em 3 The New Our 70~3. The sidelobe has The given based fluxes circumbinary R calibrated position. applied at resolution combined variable frequency observations For the et Aquarii Observations the minimizes new in integration in observations National 6 constant described the H with continuum and 0.8 Observations is in al. which em equatorial coordinates in§ with our in the on maser at position the in Inc., of II © the on by a) removal; 6 II. far scale this observations nominal 1985) and 6 the in em region sampling data of 2345-167 a the 2345-167 American in III. Kafatos, 6 6 If observational OBSERVATIONS em B-configuration 1987 and, under to Radio the removed 50 observations antenna-based amplitudes em is self-calibration 2345- Centimeter at work (IF) resolution signal with these 36.6 configuration next emitting or 6 for in the SiO (nominally and were presumably specifically 6 time from nebulosity. em MHz. NRA0 images reveal of thus, indicates thus, Hollis in em. September R and cooperative cf. Astronomy 6 at bandwidth of position km. antenna-based before section. were the centroid previously maser the 0-configuration continuum flux Aquarii galactic to over 167 em Clark combined (exclusive Hollis, of 3C the all from details totalled were noise, The regions in at Spacing et 3 failed for and R made Astronomical Continuum densities 48 to observations a observing location , VLA CLEANing al. AND least were the and 4,860 wide 1980) The Aquarii phase Observatory composed the phase probe of were 2.189 VLA Thus, agreement and 6 coordinates and phase phases (two 22. 1987). were procedure of of to is between AlB-configuration, 357 R reported jet em of are DATA to knots two in combined atmosphere data of that importance range a;= MHz), 2345 the show 50 Twenty-six the between made the Aquarii, observations center Michalitsianos phase ± of calibration obtain self-calibrated phenomena the 8 south the smaller of we and observations Observations errors, runs MHz for discrete spatial 0.008/2.132 were 23h41m14~269 IF 5.59/5.64 the reduction and array REDUCTION hr with -167 engulf SiO is of R (a discrete of A-configuration also of 2000 utilizing to the pair 55 (one errors operated 6 (ASCAL of observing maser Aquarii spatial several in particular l radio of the and establish to interleaved = R em than which Society antennas move the maser minutes, maps. two by and the obtained of bootstrapped of the knots and the antennas 66~5 8 National achieve purposes. Aquarii Jy emission, two observations assuming observations of of in general in hr this the is maps IF the frequencies. an by A-, ± spots. SiO time) in R SiO were 0400 in for individual R formed for observing 1983 emission. in and 0.009 Associated which and interme­ near pairs IF system's order work analysis sessions limiting KAFATOS Aquarii Aquarii the method B-, the respec­ the varied Science epoch maser maser AlPS) which 2 a • 2 for LST, pairs were were This with {J b then On­ and flux and and the the em for 3C Jy. = = A­ IF 1 Provided in in to is R is 1 6 2 ET components central B-, plot sets from from complexity circular effective calibration equal data cant 25, 22.7 that which weighting A. resolution with belonging was 44~0(2), points structure struction such, expense across also of of 2':33 B the tapering the received part -3.89 and A' Figure the 30, the and FIG. "' IllY "' "' ci 0 discrete suggestion -15°33'44" AL. -15'33'40" scale, the u, by were shown seen achieved to feature sets uniformly x these mJy B' smooths 50, H n H as weight. central D-configurations v number beam- were were the centroid 1':39. 1.-A shown previously the of determined beam 75, of equal data the 42" in 43" 41" beam-•. of in 1 in brings corresponding region of then 6 is to this here projected data shows diluting 100, of em was Figures both enhancing entire naturally the Figure 6 uniform 1 not A. a NASA • With subsequently figure em the Note H continuum is single is and An points in weight); of of 125, feature R of combined weighted Using 14'.45 sets; completely contour Contour applied. obtainable 4':49. II features out Aquarii SiO new constructing binary a by the data the improved and, enhances and reported region a weakly 2 1 the Hollis configuration. with baselines; in the field highly maser Cl is and 14'.40 R with weighted Astrophysics the SW the therefore, 150 As plot emission weak the points system the levels the binary (Michalitisianos compact Aquarii in 6 to u, a resolved Band eta/. The multiples 2, seen at same feature one of extended em of Figs. suggestive resulting emission emitting v sense resultant a 14'.35 prominent different NE Figure shown in the a <>11950.01 data the sensitivity view system and itself 30 (19861 uniformly weighted beam are (cf. taken combined at in Figure 2 the rvos studies previous (i.e., data B'. distribution continuum feature (cf. highest and that not k.A. and Fig. 14'.30 B' points, of Figure a are resides resolution extended of spots Figure bow 3 resultant is Hollis using ~ the each time radio which is included 3, emitting synthesized Gaussian is 4). configurations. set at 23h41m -3, not 40"', et each discrete cannot 0~48 central 2, rms generated shock Larger Data 14'.25 a/. that at B to coincident within VLA employed resolution 3, or et 3, observing before data where structure 1988) (Sopka map 3 Figure 4, position is baseline, al. extended of in application baseline emission x clearly morphology 5, of be source clearly synthesized baseline, scale data 14'.20 0':48 the image 1985). 0':33 6, 7, 6, System features the H noise sources weak, whose readily sets taper field a the of 6 II with features, taken by 8, confines x 2 14~277(10) et em of It global in and region level 14'.15 shows obtainable 0':33. 10, data a associated shows a were regardless of pairs. structures weighting peak the can al. The within u, structure low-level seen any Vol. counter­ function the data view. in 2 15, 12, receives beam of and, inner which v at results of 1982); be such At feature the signifi­ point flux 6 of at con­ data data very that self­ The and this 346 seen the the and em this set the the A-, 20, jet as 5" as is is is 1989ApJ...346..991K its and resolution mJy using Figs. No.2, scale for and and central dynamic (and feature the resolution; Aquarii more peak 250, resulting 1982 '0 -15'34'00" "' "' 0 ci FIG. counterpart FIG. 200 beam-•. such and global 1 in features, flux amorphous (Sopka VLA "'300, opposite and '0 "' "' -15'34'00" ci 0 -15'33'25" proximity B', 3.-A multiples 2.-A jet 55" 50" 45" 40" 35" 1989 450 resolution of of H a 2). which however, data range using 7.25 weak 4':49. © Contour multiples 45" 55" 40" II properties 50" 35" 30" et 6 such respectively; 15'.5 6 B' em American al. mJy region. taken em is than to) can of VLA 15'.5 one The as contour s- weaker radio achieved Hll-- of2':33 1982), the the contour A beam_,. C2 be • levels B. central of data in can rms another central seen and 15'.0 the the source and of in At 15'.0 plot x shown be map @-BEAM taken rms A' integrated --BEAM flanking B'-- 1~39. H B plot Contour A, this inferred in this H this shown of II and Astronomical map noise a(1950.0) 4 B, <>11950.0) II a region Figures are in in (see of The 14 work region. achievement 14'.5 30 and the 5 point noise a .5 the B' position -3, in level k). levels by central Table flux naturally (so A-, Fig. D are now central tapered ~ = 3, a Radio level of configurations 23h41 by 23h41m marked) NE 4, 1, B-, shown 14'.0 14 1, we 29.3 similar 5, has H a 1 5 cannot 2, and of .0 protrusion factor 7, m fluxes). H feature II angle image weighted !J]y and emphasize 11.2 9, detected region is are II D-configuration has 12, region 13'.5 quite beam Society be ,.Uy of 5, morphologically 13 of 3 B 15, a relative 7.5, readily 5 -1.5 (so .5 was is the peak with beam_,. image emanating 30, -•. its (see 10, marked) remarkable "'170, R discovered 60, counterpart, and Only flux a Aquarii seen 30, legends that 13 resulting 100, of to appears 5 Smaller 60, • of .0 B with at the has 650, R from 8.86 150, and the the 100, this Provided jet to in R AQUARII a a (i.e., images, for feature and central optically Figure seen, epochs, density optically directly The However, tive the minutes, than were responding were were whose resulting time) bandwith Spacing employed observational 0000 tions. with and For In With Continuum em features hybrid spectral and of the S2 S1 C2 C1 C1 B' A' A B features spectral observational by 0230 2 the 0':49 S2; this NoTES.-(1) the the 1.889 1.858 data, tabulated ...... there order and made, + ...... em for S2 On-source Feature positional A'. INTEGRATED 5. H we C2 a 2 of feature the A/B the NRAO compared 2 (1) conversely between indices thick are respectively. synthesized are thick LST data thus em x 550 the of 0400 em The II at R This ± ...... ± convolved 1.85 b) are POSITION to S1 configuration. 0':34) severely index, to IF region assuming not 50 NASA 0.015/1.879 value. 0.021/1.865 observations, rms 2 suggesting image. Aquarii k.A. methods 2 (Fig. and on The this 2 of for and central and two quantitatively LST MHz (see em pair Centimeter Jy apparent VLA em Gaussian Figure these 6 1987 and noise antennas uncertainty integration IN 1 (2) frequency. 5). oc, thermal, blended resolution ANGLES S2, CENTIMETER for u because in thermal (nominally discrete 6 Table the observations THE The B for bootstrapped (4) on error beam em and Astrophysics in (mJy) features. both Flux and made a the November 0.2 4.9 using 0.6 and 3.2 2.3 that 1.5 (2) H as both (3) level The negative IMAGERY feature 4 in 2 the Flux 1987 ± 6 ± in B' cannot II OF on See and were two em 1 the vicinity em TABLE Continuum taper we is images 6 while 0.014 calibration O.Q18 2 varied hybrid 3C 2345-167 region features RADIO flux, as is the both a the em the em IF AND 0':46 is Quite November 6 the data is time compare data used 4 IF spectral spectral employed one flux A' OF 14,940 em data. 48 2 data pixel-for-pixel shown times convention pairs. indicated applied Jy A' F, 2 em Jy be pairs of (mJy) 6 7. FEATURES FIGURES and 1 10.0 are with CENTIMETER x of is (4) between A/B data, of 0.9 2 0.8 has 1.4 C1 em the expects on (exclusive of is detected Twenty-six values) resolve on (5) Flux probably R estimated (S1 0':27, em Figure index the likely better Observations positive Figure A' at data 1987 Data Aquarii MHz), in For index observations same separated shown configuration 1987 a a thus totalled the and to is 4 1-4 fluxes in slightly SiO Figure constant similar DISPLAYED C1 for and at not by and spectral argues the non for Position the of the November F 0.3 suggesting in 6 -190 -170 -209 -231 2 to November 1 Angle phase FLUXES and S2) this image -45 -29° -55 System apparent em (5) 4 oc do Figure utilizing maser S1 spectral 1 of the em in be the 2 were antennas a thermal. 6 between and observational of u do feature. v«, C2, with 367 em 4. south em 10%-20% not larger by stellar array Figure and index resolutions. 6 for error image 2345-167 and center 2 AND As where not em shown but of 50 data, 22.8 the obtained observa­ show position positive between 1 in em and a 1, 1, 1, 1, 1, 1, 1, 1, 1, Notes indices image S2 can 7. can (6) 3C an image these of (6) the VLA MHz. 4 beam 2 nega­ 6 6 3, 5 2 move 3 3, 3, 2 show wind bars. 2200 were cor­ 5 S1 flux and and km. 4 993 of 4 4 vis are the the em 2 S1 IF 48 be be 55 in is 1989ApJ...346..991K (feature moves (a~ of is al. Hence, while from features 994 opposite Aquarii H from changes to is al. 2 the B 0':46 ;;o feature outward due thermal beam- south -15°33'46" are Here VLA multiples reference 1), "' "' 6 -15°33'40" ci quite (optically and found Relative indicating FIG. an II 1985; shown to 1985) spectral by data region), we of +0.6 the shock-wave 1 optically nearby a 45" A. 44" 43" 42" , 4.-A 41" further 0':27; 3, the the complex with (Hollis B see of of emission taken Contour with system mildly B that Kafatos, from sides provides which central in the 250 for ©American that spectral thermal 14~55 to the a and 2 this thin). suggests Fig. the protrusion index em NE in rms et features the a out III. their pc. central of the heating beam thick, the a/. position contour (cf. spherically H levels but relativistic B' • 14~50 indicates map 2), jet the From probably DISCUSSION central This 1986); Michalitsianos, II the hybrid radio optically index strong for a) Kafatos gradient region, extend largely size the feature ------BEAM H shown noise central of thermal that to NE C2 14~45 The outlying plot of of morphology, II spectra the these is ultraviolet the spectral AlB-configuration ~--A the distribution region H comparable newly jet and C2--- level circum the evidence an Symmetrical are 0 Astronomical NE produced thermal symmetric to features and centroid 14~40 thick, II C2 <>(1950.0) a gas. object, of to are AND 550 region. origin 3, which region, optically which A detected a (C1), features binary is A, the 4, Michalitsianos probably index are k,\ distance 14~35 Farther and slightly CONCLUSIONS 5, thermal observations are the of in nature. to tapered is is whose for which assuming = 6, NE of higher SiO nebulosity. by or due not At 88.4 23h41 that symmetrical, continuum Hollis spectral 7, steady is with 14~30 Jet the A bipolar thermal, gradient thin, synchrotron 8, jet, maser seen to nearly the p.Jy peak of (optically image nonthermal. 9, m is out, jet of feature feature a in the resulting 10, in NE shown 14~25 1986). beam as Society state thermal emission (i.e., a flux ~2500 excitation index the 0 6 optically features of 12, 1982; zero and C> mass the one distance em jet C2 of R - 6 is 14~20 15, 1 C1 C2) ideal Aquarii em . collimated Moreover, the data in and thick) resolution analysis extremity Toward (Hollis spectrum is ~3.98 proceeds emission 20, Hollis plotted Sl ejection data (central KAF Figures AU thick source. As is typical NE outlying (Fig. 14~15 case), and and • non­ to than using one and (Fig. mJy and jet on the A for Provided et S2 et 30 R 1). of it TOS shown derived optically tral ET ;;o jet jet/counterjet "' seeming "' determined 6 estimate corresponding -15°33'40" central This ci which with the system star. feature accretion and 7-D.7 and observations and ionized, national the that the which highest because 10 104 -15°33'46" ~ The 5 1.5, index FIG. and spatial knots NS em- AL. K), counterjet by 3) Further, increasing result SW arguments are from 42" 44" 43" 45" respectively. 41" yr, thick radio is is indicates 5.-A values. appear H B excitation . it they and -0.3, the stability 3 the Ultraviolet that presumably counterjet not ; disk data because II of is respectively. distribution is 14~55 and these (Viotti contour emission region. largely accelerated more NASA discrete Clearly obtained are R -0.2, indicate features in directly the thermal eventually (see NE to distance Aquarii For Fig. 14~50 a densities to of also electron et -0.1, be more they emission The plot feature amorphous features Kafatos, the being I Explorer As follow); features al. an (see (6 sources, SW the located Astrophysics tend 14~45 hotter from that of exposed for em foregoing NE +0.1, listed 1987). is 6 are electron text). Such from at amorphous the C2 known radiation blend shielded of imply data) this to the density jet . 14~40 C2 closer is observations spectral a(1950.0) R lines A +0.2, Michalitsianos, moreover, than A' non satellite in the become immediately as Aquarii short and over accretion type and and to SW with a thermal, and Table temperature seen to 14~35 central suggests +0.3, observed cooling Fig. to by indices the the range be cone emission several B = A structure counterjet the cooling the B' 23h41m the 4 which comparable in a central by 14~30 (see +0.4, Data 1, (2 high-energy were while soft are since of disk star taken overall Figure emanating source em thick flux for A factors that time features contours NE in +0.5, features data). 14~25 X-ray weaker indicate and has initially and surface the System times T. compared H values the the accretion with corresponding scale of is nebulosity of 1, and ~ not II (Hollis Contour Cl, both Hollis 14~20 of knotty in the source, Cl ne NE R ultraviolet 10 region ionization the in Figs. in radiation +0.6 from C2, than intensity and (7inner yet Vol. range and ~ that 4 ~ indicate formed, Aquarii central the K, 3 of 14~15 Inter­ and et levels A disk. been spec­ 10 1986 with and NE but 346 the the the the the are C1 we jet al. 3 of of ~ A - 2 1989ApJ...346..991K (Hollis we because SIO 3 em- si_on. (Kafatos, clump either in details The the vibration high_ requires clumps emission. et clumps length The_ 1, meter the the thick. temperature where heating region roughly however, region evi~ent SiO SiO source. similar an em- and optical limit thick to we with unresolved which h~od No.2, 1985) 1014 "'2500 b) x There The and radiation de~sities those intense have JetjcounterJet v hypothesis The assumed 10- Xs;o mere maser 2 masers 3 excitation heating the em Except temperatures = . and on require have (Elitzur This a of of Likewise, nH (see required of surrounds 1989 e~ L are depth of K to The in have can (Sl 1 5 It in SiO is the is S1 singly (Lane . that inferred the :$; the Michalitsianos, ~~- state It the state, fact the (em- thermal. to material IS Thu~ the Figur~ © the n~x~T- the accord independent south bath Hollis most inferred and implies place also following and 10 is positive the emergent observed detection avoid for 1986). Maser 'v=1-0 no SiO is_ must American ofthe maser temperature SiO that that fraction a observed therefore pump, SiO 1980). of 5 1982). 3 that evolving which and likely only S2 ) R 6 with high provide of cosmic S2) to of em, 4, likely the features emitting is em with an et for an Aquarii dissociation the the maser Hence, 2 The 0 in radiation be running the v and near SiO support SiO from_the = the these · is al. em of symbiotic size 5 spectral molecule, = Av These upper counterpart SiO every densities The we IJ;;::: relation: so from accomplished late-type is the of of 1.3 NE at a expected hot central 2 bn~ary evidence Coincident highly 1986). spot 1-0 the v hydrogen radio the the "' column Boltzmann "'1750 silicon late-type far S1 silicon find and em shows = region. least maser are southern for densities X region. region, in Astronomical and and 2.6 3 both companion pumping foregoing result position a limit high 1-0 into and vibration 10- in km sizes SiO arising emission optically Hollis the bathed indices emission significant The nH;;::: H significant sta~ x in of which implies Omicron the SW in SiO "'1000 K transition exists, 24 s - to of sides S2 that abundance, densities 10 temperatures II the the maser masing an Assuming of in Av in SiO Independent density, nHLXs;oAv- or of Radio above existence region system 1 even galaxy 53 would 2 jets features produce and distribution 1986). in Figure (Hollis maser late-type 2 from of gas otherwise (km in ambient shock exhibits pre-main-sequence scheme x and, em- its of estimates (e.g., thick both x occurring transition south detected; because the the K; two be 10 to greater region the a phase Ceti Continuum population 10 the that process dimension s- provides then is 9 the in R thick are 3 L SiO continually thus, following 15 the at Elitzur stars, 1, et cones high cm- 1 compression free-free are of fact K- level Aquarii continuum Society ground ) (em) excess of (Mira), namely SiO proposed they we stars em al. central is associated gas. the required 1 SiO S1, maser be rather cannot of differentiation Mira 0 are accretion at shielded R the ' that 3 in · densities are 1986), detected in 5 be . "'10 maser populations for comparable is of the 2500 S2, in Aquarii support same 1980). The The molecules. , the of consistent R linewidth, of Emission of the ultraviol­ emission, could is state, all optically alllikeli­ optically each manner: emitting ionizing the variable Aquarii rarefied "'10 and 10 Si/H specific excited heated. unique exceed SiO for Xs;o ,.., K so other, upper shock • -10 emis­ radio path­ time, these from Here with star. 10 ' of disk dia­ and two R the the are the the 13 for far Provided (1) (2) be = as = in 18 11 - a AQUARII for (Davidson formed clues edge-on accretion estimate companion. difficult over, is ional of angles 2000 that the radio provides sphere from 10mzed. along compare account of et Johnson 2n that mdicate torb, without invoking nearest tional spherical entirely emitting emitting of layers Michalitsianos, v mentioned regio?- radio ~m. co?lpo~e~t pure 1981), km MI~hal~tsian~s, abl~ ~h~re -250 "'7. ;;::: oo also The R 2 the al. the C "' torb. x grains s- s-1, by the x the a Aquarii margm Sue~ yr. IV, from optical period H rL~/(GM) 6 concerning knots, emitting 1985) Mua flow accounts sphencal AU the properties 1 or (see 10 IS required of XH r~quisit; x astrophysical Assuming by orbital II to (for disk to the S Indeed, which for the layer. possible from r~gion as the a wind to 1980). shells disk u the 10 gas) jet/counterjet = to em- the (Kafatos, the speeds (i.e., understand b Table .. natural tidal and shock high by, 4 stitutmg the ambient tprec, the f?r presence Thus? a Michalitsianos spectra Further, ne/n!l NASA account radius is relationship Mira km . variation (Kafatos line molecular Michalitsianos with if region 112 period indicate a presumably, not for and wmd as any are and ) range to On McCray regular If as mass _no jet) c) imply of . s- 1). which . the densities jet that speed the are the of a From the no provide explanation allows variable Application only "' used, a mass r 1 the Hollis (Solf reasonabl~ Analogous likely Michalatsianos, magn~~ic the result Hollis sight these cannot existence for phenomena densities "' and jet of 10 Astrophysics the somewhat mass observed stellar of parameters allowed high exchange the observations the and a of is the 10 R 11 progression a the accretion axis, the range the other source. geometrical preshock and lower this an 1980), accretion between (see the 13 slow accounts Aquarii morphology em- values for 1986). loss of emlttmg of sufficient in 1986). presence compared et the Michalitsianos and observations produce nearest ambient em. the relation Ulrich and, position the compact et Willson, fields al. by of are the of the 3 would of hand, e~timate limit for cool to wind where the (Elitzur thinner between Thus, al. This The Jet a (1988b) in shock inferred "' in the If the case jet gas) because thick the the hydrogen "'10 SiO-emitting for equation 10 1988a), disk, (Hollis are symbiotic hot outer of 1985) the shock regions Models and general. of sufficient radiative ( arguments density disk, geometrically from continuum v ultraviolet accretion is may increase -? angles to Garnavich, the Data oo ejection detailed binary of to radio the a 5 compression of obeyed present companion than accretion density 1980), estimate "' herein. Hollis M the fast the if em the from regions but 1500 compression. td, star XH of provide speed 1982), 200 the theory et disk and 0 precessing, of - are of (3), jet SS extended feature ( and the speeds Moreover, System yr wind to more al. compression 3 -0.1, acceleration orbital star, then is by 0.6 the disk of disk the individual the investigations km km by and - (see of 1986). Hence, in Mg in observations 433, we from period, range arranged interior "'1 be 1 1985) we region the of that disk and Mattei gas a em- the a we SiO (see important R the thick (v s- but s favorably the can (Kafatos scale the say). factor is I~ if comfort­ -I, estimate Kafatos, deduced with partially position M precess~ one Aquarii 1 the period parcels t eclipse obtain the More­ that nearly 3 of Hollis atmo­ maser prec which maser :$; afore­ imply direc­ could is 0 (for thick solve from for td disk it , (i.e., It SiO size can hot 150 10 the 995 the we jet (3) "' = at of of in is is is a a 3 1989ApJ...346..991K JAN ANDREW Space MEN MosHE find extremely Clark, largely Johnson, Wallerstein angles density, obviously geometry, Lane, Elitzur, Kafatos, Kafatos, Bridle, Hollis, Hollis, Kafatos, Herbig, Davidson, Hollis, J. Merrill, vich, the retion Arp, where em- from ion large-scale This For tude both and a of range 996 1985). J. L103. W. Zadeh, Ap. 853. mean Since The the remains Mort binary M. H. R a AS 1. 3 torb A. J., less the B. amount A. equation J. J. and Flight for gas M. 1986, G. Aquarii, P. extended 10 li Taking disk in 1981, P. KAFATOS: M., ELITZUR: 289, M., HOLLIS: G. M., M., H. properties F. H. M., M., (Paris: and thermal - W. is K., H. as 15 than SW the 1980, 1982, feature G. density Table 1980, 1987, M. and helpful 1986, the Hollis, Michalitsianos, ©American -10 Michalitsianos, Ap. 20 the 765. orbit an Kafatos, Mattei 1980, diffuse Kafatos, and 1934, unseen in evident 1986). is V Center, 1980, MICHALITSIANOS and Ap. Ph.D. Michalitsianos, prevalent 00 ESO), power J. yr, those Optical of Astr. Ap. 16 the cross Canadian McCray, orbit not we (4) IAU (Letters), Code is Ap. 1. NS (cf. 1 J., B). Department em, power Ap. which Department in but J. and NE M., the assume cross at may M., NS Ap., On thesis, exhibited M., J., 240, that p. (Letters), 1981; occurring, Circ., found the Merrill1934, from J., Greenbelt, nebula sectional Jets provided 53. and the 81, determination difficult, L appropriate jet 630, escape Michalitsianos, 89, Michalitsianos, R. 237, the nebula 553. J. can 309, A. range = A. reflect 2.5 312. University is sectional is Michalitsianos, No. present in 1980, Phys., properties features 377. G., G., n/2 the Space v Kafatos 840. for A. other within 321, L57. more Astronomical oo x 3535. are be Kafatos, G.1982, velocity Ap. and by - 64, the of 10 10 considering radius is which of counterjetjjet and x L55. the then MD more 100 epoch. approximated J., 3 Physics 30 353. hand, Data piv'!, Physics, of Hollis, -10 the than jet even if the radius 1940, for (ESA 241, vagaries Massachusetts, A. :s; F. A. Nature, and M., for km of components the 4 extends of A. of G., R L range G., the than lJ, 20771 and YusEF-ZADEH: em 1082. capable if 1. 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