Revista Mexicana de Astronomía y Astrofísica ISSN: 0185-1101 [email protected] Instituto de Astronomía México

Loinard, L.; Rodríguez, L. F.; Gómez, L.; Cantó, J.; Raga, A. C.; Goodman, A. A.; Arce, H. G. A REASSESSMENT OF THE KINEMATICS OF PV CEPHEI BASED ON ACCURATE MEASUREMENTS Revista Mexicana de Astronomía y Astrofísica, vol. 46, núm. 2, octubre, 2010, pp. 375-383 Instituto de Astronomía Distrito Federal, México

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How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México rde USA. bridge, M´exico,Aut´onoma Mexico. de M´exico, Mexico. de noma Universities the Research at Cologne). Planck Astrophysics and Max Bonn and of International Astronomy for the School of (Member many Mexico. M´exico, Morelia, Aut´onoma de Nacional Astrof´ısica Astronom´ıa y de Mexicana Revista a ytm ihtreo oemmescnb dy- be can members more or three with systems lar 6 5 4 3 2 1 opc tla lsesa ela utpestel- multiple as well as clusters stellar Compact .Loinard, L. aeUiest,NwHvn USA. Cam- Haven, New University, Astrophysics, Yale for Center Nacional Universidad Harvard-Smithsonian Nucleares, Ciencias de Aut´o-Instituto Nacional Universidad Astronom´ıa, de Instituto Ger- Bonn, Radioastronomie, f¨ur Max-Planck-Institut Universidad Astrof´ısica, y Radioastronom´ıa de Centro ESESETO H IEAISO VCPE BASED CEPHEI PV OF KINEMATICS THE OF REASSESSMENT A 3 ao mlcnqelsmvmetspoisd saetel son Estos a˜nos. estrella 10.5 esta separaci´on de de una propios con movimientos Array los que Large implican Very datos el con tomadas Cephei n smt´ae o eaimsd ycio,oe adsrbc´ndlmaterial distribuci´on del la largo en deber lo eyecci´on, o a realidad, de Haro mecanismos en sistem´aticos podr´ıan, Herbig circunestelar. los desplazamientos objetos asimetr´ıa en de Estos una sucesivos a pares sistem´at chorro. de desplazamientos bisectores su los los de estrella de hab´ıa de inferido una se este Cep es el nebulosa PV no hacia de cercana Cephei estudi velocidad la PV anteriores alta en iluminaci´on hab´ıa que de La sugerido se r´apidos, sugiere la como movimientos resultado con domina Este desbocada que B2Ve 7023. reflexi´on NGC estrella de la 200775, HD VCpe,tknwt eaaino 05yas hs aaso htteproper the that show data These are . 10.5 this of of separation motions a with taken Cephei, PV smer nteeeto ehnss ri h itiuino h circumstell Words: the Key of distribution the an in from or result Har instead mechanisms, Herbig might material. ejection sys- by of shifts the the pairs systematic suggested in from These successive as asymmetry inferred result of flow. star been its bisectors This had runaway along the Cephei moving knots of PV 7023. rapidly displacement of eastward NGC a velocity tematic large not The tha is reflection studies. star Cephei nearby B2Ve previous PV the the 200775, that of HD suggests illumination of known– the –previously inates those to similar very 1 . NACRT RPRMTO MEASUREMENTS MOTION PROPER ACCURATE ON .INTRODUCTION 1. a a˜no mas 0 .F Rodr´ıguez, F. L. rsnao o bevcoe el srlad r-euni rnia PV principal pre-secuencia de estrella la de observaciones dos Presentamos epeettoVr ag ra bevtoso h r-ansqec star pre-main-sequence the of observations Array Large Very two present We − srmty—IM niiul(VCp S:jt n uflw — outflows and jets ISM: — Cep) (PV individual ISM: — tr:pemi sequence pre-main : 1 ; µ δ eevd21 ue1;acpe 00Ags 2 August 2010 accepted 15; June 2010 Received +0 = 1 .G´omez,L. µ . 2 α ± cos 1 . δ a a˜no mas 8 2 +10 = , .Cant´o,J. 46 ABSTRACT RESUMEN 7–8 (2010) 375–383 , . 9 ± − 1 3 3 u iiae o acncdspara conocidos ya los a similares muy , . .C Raga, C. A. a yr mas 0 he tr icuigB tef r oigaway moving where are Orion itself) in BN region BN/KL (including the stars of three that case is promising far, most so the process Arguably star-forming the 2000). im- of (Reipurth significant outcome very a the have stages on pact could earliest they occurred the star-formation, they during of if frequency because sufficient evidence events, with observational energetic direct these for im- of is search escape It to can stars. runaway portant sufficient– become and is members, birthplace acceleration system their the the the of to –if more lead which or can one of them acceleration body within few close occurring Indeed, encounters 1967). 1991; Allen Mikkola & Ruiz, & Poveda, Valtonen (e.g., unstable namically − 1 ; 4 µ .A Goodman, A. A. δ +0 = µ . α 2 cos ± 1 . δ a yr mas 8 +10 = intrinsic 5 dom- t n .G Arce G. H. and . icos 9 − os. ar se ± 1 o , 6 375 © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México A04.I slctdaot1. 2002a,b; about Goodman located & is Arce It 1997; GA2004). 1994) Kenyon (HH) & G´omez, al. Haro Whit- 1997; ney, et Devine Herbig & (Li Bally, giant (Reipurth, star well-studied flow Ae/Be a Herbig drives a that PV Cep is PV (hereafter 1) candidate. Cephei (Table potential another PV be star might Cep) the that suggested dynamical a The occurred have ago. to years 2009). 500 appears mere case, al. al. that in G´omez et et disruption Zapata 2005; massive 2008; the al. of 2005, center (Rodr´ıguez et the outflow near KL be to happens which Hri 90 ilsadsac o h nieregion entire the 7023 for 430 NGC distance of a of yields illumination 1960) the (Herbig dominates that star taot3 ms km 30 about at 376 oes,a le Hpiswr osdrd This considered. were pairs HH older as increasingly systemati- so, and were source, more the segments of the eastward found shifted of GA2004 cally however, bisectors Cep, station- the PV is of that latter case the through the if In pass — ary. flow to the expected driving are source the suc- knots such of joining from segments pairs distances The cessive equal jet. pairs its nearly along successive at Cep of PV located distribution knots the HH sur- follows of of argument gas study strongest the a The analysis from of careful Cep. morphology a PV and on rounding kinematics based the was star of runaway a be ob- 1974). Rieu pre-main-sequence & associated contains (Lepine low jects that is stars of 7023 young number NGC of a cluster of compact GA2004. estimate a by with older used somewhat pc the 500 with consistent is VCpadNC72 r ttesm distance 361, same (MWC the parallax 200775 trigonometric at HD measured are of The 7023 Sun. that the NGC likely from very Be- and is 1981). Cep it kinematics, al. PV shared emis- et this CO (Cohen the of itself of cause 7023 that NGC to from similar is sion velocity emission centroid CO the its and of 7023, NGC nebula flection oda re(04 eefe A04 have GA2004) hereafter (2004, Arce & Goodman h ugsinb A04ta VCpmight Cep PV that GA2004 by suggestion The − +155 91 c(ermne l 97.Ti value This 1997). al. et (Perryman pc − 1 rmacmo on forigin, of point common a from enpsto EunxJ2000, (Equinox position Mean Distance pcrltp A5 magnitude R-band type Spectral pc 2002.26) V 7 = ◦ . eto h re- the of west 5 a)teB2Ve the mag) 4 HRCEITC FP CEP PV OF CHARACTERISTICS ONR TAL. ET LOINARD AL 1 TABLE oinbtenP e n G 03 nthe In 7023. NGC ( and paper Cep present PV between motion and Cep, PV surrounding not kinematics gas the the of of of morphology analysis conclusions and an the on that based were however, GA2004 par- Note, star identifiable) in- runaway cluster. (still a might ent its of Cep from example PV ejected an Thus, dynamically with us 6). provide Figure deed their (see ago e a eneetdfo G 03aot10 about 7023 NGC from ejected been had Cep n e ai esrmnso h rprmotion proper 7023 itself. the NGC Cep of PV in measurements of star radio brightest new the and of optical motions published combining proper measurement, direct a httet h rbe fa model of analytical problem an the Cant´o developed & treats that have jets. (1995) HH curved the some Raga explain by to presented proposed morphology been have merical) onsams exactly GA2004 almost by points obtained vector velocity the remarkably, oret e2 ms km 22 be detached central to fully the source of are velocity flow the estimated the GA2004 along clumps, knots mov- Assuming HH is the surroundings. it that its that to thus, relative and the westward to position, ing current somewhat its be of to east used source the that suggests oedtce cup”ta rvlo somewhat on be- travel eventually trajectories. that velocity straighter “clumps” ejection detached jet come larger the the by On in created surfaces changes (1995). working Raga large Cant´o the hand, & by of other jet, predicted model the path jet the along steady following created travel are working they knots) and small HH velocity), (i.e., ejection surfaces jet the moderate in by changes (caused variability regimes. different low-amplitude two identified For and sidewind a Raga a in & jet of Masciadri simulations recently, numerical presented More (2001) sidewind. a with α δ d R 67 = 430 = 20 = 11 = eea hoeia oes(ohaayi n nu- and analytic (both models theoretical Several nadrc esrmn fterltv proper relative the of measurement direct a on .AR-NLSSO H BISECTOR THE OF RE-ANALYSIS A 2. ◦ h . 57 − +155 1 45 91 ′ m 38. 53. pc ′′ 681 s 9550 §§ ± n ) ewl rvd such provide will we 4), and 3 0. − ± ′′ away 1 RESULTS 008 0. sedsuso in discussion (see s 0014 rmNC72,a fPV if as 7023, NGC from steady e interacting jet § ) Most 2). variable 5 yr © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México h est fteabetgs ntepeetcase, present the In gas. ambient where the of density the olwn A04 eadopt we GA2004, Following au is value a on pe ftecupmtra,and material, clump the of speed sound mal Here, hto t e.Tevlct ftesa eaieto relative star be the to of taken velocity is The surroundings to jet. the perpendicular its the exactly of to direction that relative a (follow- moving in assume is gas we Cep ambient Cep, PV PV that GA2004) of analytic ing case that the examine in To solution simulation. fully numerical obtained of those in to case similar solution, trajectories analytic idealized produces completely which the Cant´o et a has that however, clumps showed trajec- Recently, detached (2008) the clumps. obtain al. equa- the to of the numerically tory integrated motion and of be- had tions clumps, ejecta the detached that come assumed GA2004 pairs, HH foefrhrdfie h angle the defines further one If h qaino h rjcoyi ie analytically given is trajectory the by: of equation the yG20 seterFgr )sosta h an- extremely the agree that trajectories well. shows numerical 2) and Figure alytical their (see numerically GA2004 obtained by path using the obtained and parameters trajectory these analytic the between ison e32k s km 3.2 be ρ soni iue1)i bandfor obtained is 1a) Figure in (shown oyi aaerzdb distance trajec- a The by parametrized description). is schematic tory a for 1a Figure mass of clumps plies 08 ie by: given 2008) rvddthat provided 0 x 2.1 1 = nteraayi ftebscoso successive of bisectors the of analysis their In = M nltcslto o ul eahdclumps detached fully for solution Analytic . ξ tan . v 5 ∗ sacntn fitgainwoenumerical whose integration of constant a is ξ ≈ y × and 4(atoe l 2008), al. (Cant´o et 14 = θ 2 10 − − × 1 3 v s 4 10 ssgetdb A04 compar- A GA2004. by suggested as e 0 cm s s M 0 0 − r perpendicular, are ≈  v 4 − ≡ 0 6 3 r jce tavelocity a at ejected are M v v tan . odfi otedt points data the to fit good A . = 4 3 ∗ 0 4 ⊙  ×  p θ ftevlefor value the if " ξρ 10 Mv v = 1 ∗ 2 0 18 − c + v v 0 4 4 ∗ e  m hs ntr,im- turn, in This, cm. v  v , e 1 θ e 2 1 / 5 ms km 350 = − . v as 3 ∗ n individual and , s . v s v c 0 0 0 ∗ RPRMTOSO VCP377 CEP PV OF MOTIONS PROPER steisother- the is sin y ssimply is 2k s km 22 = Cn´ tal. (Cant´o et c θ stknto taken is  1 − v / e 4 1 ρ # (see and 0 − (2) (3) (4) (1) . 1 is , n o otnosjt[ae c;see (c); [Panel jet continuous a for and r eivdt einzd oteaporaesound appropriate the so is ionized, speed be to believed are negn psdso xrml ihaccretion/ejection. high extremely of episodes undergone h stemlsudspeed sound isothermal the beasmtosfor assumptions able h aso h jcab erytoodr fmag- of orders two 1 nearly about by to ejecta nitude, the of mass the see (b); [Panel clumps detached fully the the represent for show lines fit dashed to circles the best according and filled source GA2004, the of black to results relative the The ejecta (c) the of and positions (b) system. A04used GA2004 ftesa,teevrnetmvstwrstelf along left the reference towards moves the of to environment the frame respect star, the with the In of star the environment. of surrounding the motion the to perpendicular in() ti la htt banasmlrvleof value similar a obtain to that clear s is it (1), tion i.1 a ceai iga fasa hc jcsa ejects which star positive a the of along diagram outflow Schematic bipolar (a) 1. Fig. v iprino the of dispersion trms hnb nrae oaot4 ms km 40 about to increased be then must star 10 00cm 1000 a,te utb eymassive very ionized be of must clumps they detached from fully gas, ejecta indeed the are if that Cep conclude PV We fit. good a obtain 0 e − 7 for oices o40k s km 400 to increase to tsol emnindthat mentioned be should It sacneune nti cnro VCpms have must Cep PV scenario, this in consequence, a As y 2 ai,pouigacrauei h ioa outflow bipolar the in curvature a producing -axis, M c ⊙ 0k s km 10 = − c oevr h rnvrevlct fthe of velocity transverse the Moreover, . 3 ≈ h jcams tl aemse forder of masses have still must ejecta the , 0k s km 10 c 3 = ambient − . 5 1 . × − ms km 2 ihu eotn ounreason- to resorting without ρ 1 0 10 nteraayi,however, analysis, their In . and − oeua a.Fo equa- From gas. molecular 2 − fteejecta the of − 1 M v 1 and 0 ⊙ h yia velocity typical the , n a oincrease to has one , vni n allows one if Even . x 7 c n h velocity the and , ai,i direction a in -axis, neuto 1 is (1) equation in ρ 0 § odces to decrease to 2.2]. uhejecta Such . − § 1 2.1] to © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México ftejtcniee eecnb sue ob parabolic. be to assumed be can porti here the per- considered (GA2004), moving jet jet not Raga the the clearly (Cant´o of & are of direction wind Cep the PV side to in pendicularly the knots the of Since direction 1995). the with aligned s km 22 the that larger even be might Cep PV of 378 and where h e n h onejto h aeprbl)de- parabola) same the by on scribed counterjet the and jet the h orei epniua oteeeto.Tedis- The of ejection. motion the the This to which perpendicular in 1a). is case (Figure source the the source for the valid of is relation motion the to allel rpsdb GA2004. by proposed t ftesuc,abplrflwi ieidap- sidewind a in flow shape bipolar parabolical a a follows source, proximately the of ity fti oe oteseiccs fP e ilbe will Cep PV of case specific in the discussed to applicability model of The this results scenario. of bisector wind steady the a explain in GA2004 to required that velocity be jet. sidewind would steady the a estimate such therefore, of us, existence Let vicinity the confirm immediate Cep gas the PV in molecular (Marvelof 2002b) entrained masers fully Goodman velocity & water not high (Arce is of of matter and detection 2005) of The ejection see the episodic. flow; that ionized and an exists of base the § free- from traces emission (which the radio Cep free PV centimeter Indeed, with compact associated steady, emission “on”. of always underlying existence an is very for which however, jet evidence, continuous also therein). is references jet and There (GA2004, the Cep along PV present by driven certainly are of de- suggestive clumps fully knots detached are HH Well-defined they if clumps. an tached than along if jet perturbations curvature continuous small ve- jet such underlying given are sidewind a knots smaller HH create the a to necessary Masciadri that is of shows locity analysis (2001) the Raga Moreover, Cant´o& & of paths: model (1995). different analytical Raga along the by travel predicted that those knots developed. HH have perturbations create amplitude clumps lower earlier, detached mentioned As fully perturbations to amplitude large leading which in jets describe eo)dmntae htsc otnosjet continuous a such that demonstrates below) 3 8 h rjcoiscniee in considered trajectories The ssonb ato&Rg 19) ntevicin- the in (1995), Raga Cant´o & by shown As ate u,tejtmvso erysrih trajectories straight nearly on moves jet the out, Farther 2.2 y stecodnt epniua to perpendicular coordinate the is x h Hkoso VCpa ato an of part as Cep PV of knots HH The . sprle oteiiiloto direction, outflow initial the to parallel is § 5. neligcniuu jet continuous underlying y = 2 x λ 2 , § . appropriately 2.1 8 wt both (with x n par- and ONR TAL. ET LOINARD (5) − on 1 tance ial,uigtevalues the using Finally, ihteNtoa cec Foundation. agreeme Science cooperative National under the with Inc. Universities Associated by where oteosre oiin eotdb A04using yields fit GA2004 (5) by best reported The equation positions before. observed as the meaning to same the have eters  the environment: determine the to for (6) velocity equation required use now can we value, tain M ρ rvdsa nua eouino bu 0. about of configuration resolution angular and an wavelength provides of combination This fG20 ntecs facniuu e.W will We jet. continuous in a point of this to case return the results in bisector GA2004 the surround- explain of to its required and be Cep would newborn ings PV in between dispersion clusters– velocity stellar stellar typical the of 1c. Figure in shown is 07Jl ihteVr ag ra VA of (VLA) Array Large Very the NRAO with the and 2 10 July January 1997 2007 on obtained observations uum a 0266 ihbosrpe u este of densities calibrator flux phase the bootstrapped 3 and with GHz) 8.4 2022+616, at was Jy den- flux 5.20 adopted of an sity (with 1331+305 was amplitude absolute calibrator The weighting. natural with ages 4o h 7atna fteVAwr sd ihan with used, were VLA the of antennas only 27 epoch the first of the 14 For respectively. epochs, second ˙ . 0 λ 36 ms km 1 9 × × 10 = hs eymds eaiemto o h order the –of motion relative modest very a Thus, nti ae,w ilmk s f36c contin- cm 3.6 of use make will we paper, this In ≡ h ainlRdoAtooyOsraoyi operated is Observatory Astronomy Radio National The 50cm 1500 = ± 

v v

λ ∗ ∗ M 10 0 10 ˙ − πc − . neuto 5 sgvnby given is (5) equation in 0 = 3J n 3 and Jy 03 3 × 1 − 7 Mv stems-osrt,adteohrparam- other the and rate, mass-loss the is ρ 2  ˙ cm 9 7  M ρ 0 . 0 M nisms xedd()configuration. (A) extended most its in 0 = e 0 ms km 100 M ms km 9 3 v ⊙ − ˙ ∗ 2 ⊙ 3 − .OBSERVATIONS 3. yr !  . 3 17 yr − v 1 − / e eemndb A04 eob- we GA2004, by determined 1 − 1 2

λ / − h orsodn trajectory corresponding The . 1 2 . 7 = 07 10 1 ! − 4 =  § suigams osrate loss mass a assuming , 1 1 − ms km 1 ± 5. /  7 2 . . 8 3 64 0  v M / M v × . 2 e ˙ 2J,frtefis and first the for Jy, 02 ∗ 0 ms km 100 ⊙ ×  10 5 ms km 350 = yr − 10 10 1 18 − v 3  19 1 e ρ cm − cm ! 0 1 m ihthis With cm. 1 − − / , 1 2 3   ′′ 3 − o im- for 3 / 1 2 − / 2 1 . and (7) (6) nt © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México ta.20) h ml aito nflxdensity of type flux this in Galv´an-Madrid, for variation common (e.g., small is sources The epochs two Eisl¨offel the (i.e., 2000). between Cep PV al. by the driven most et at outflow is the gas of emission ionized base from the radiation and un- free-free the be epochs, probably to for both appears Cep source at PV The resolved of 2). (Table densities epochs contin- flux measure two to The and used the were positions 2 in 2007. the Figure given in for shown position images calibrators uum of refined catalog observations the VLA 1997 to the updated for was 2022+616 calibrator the 2003). pack- (Greisen software age (AIPS) System Astronom- Processing the Image using ical The calibrated and hours. edited 3.2 VLA, were of the data time of integration antennas 27 on-source the an sec- of with the 23 For used we hours. epoch 4.2 ond of time integration on-source +86 = tef eas h msini agl oiae by star dominated the largely of is motion emission the the emission) because closely radio follow itself, the to by traced expected (as is Cep PV by driven ue vrte1.7ya iebsln fteob- the of mea- baseline source time the are of 10.47 servations motions the proper over The sured east. the µ oresosasaldslcmn ( displacement small a shows source the of velocity the of or rate variabilitywind. mass-loss moderate the reflects of likely either most and 2004), i.2 L . miae fP e o 970 lf)ad20.0(ih) h contours The (right). 2007.50 and (left) 1997.03 for Cep PV of images cm 3.6 VLA 2. Fig. oiinadpstoa ro tte19.3eoh h afpwrsynthesi half-power The epoch. 1997.03 the at error positional and position 2ad1 ie 9ad12 and 19 times 14 and 12 δ oesr cuaeatoer,tepsto of position the astrometry, accurate ensure To scnb eni iue2adTbe2 the 2, Table and 2 Figure in seen be can As +0 = 67 5739.4

◦ (J2000) 20 4554.10 o 970 n 0. and 1997.03 for 38.0 38.2 38.4 38.6 38.8 39.0 39.2 . 2 ± 1 µ . a yr mas 8 α 54.05 cos δ ′′ +10 = 54.00 µ 30 − ybeam Jy RIGHT ASCENSION(J2000) 1 × h aeo h jet the of base The . 0. ′′ 53.95 vl,&Rodr´ıguez & Avila, 4 A=+39 = PA 24; ´ . 9 − ± 1 h m os ftefis n eodeoh,rsetvl.Tecr The respectively. epochs, second and first the of noise rms the , ∼ 3 RPRMTOSO VCP379 CEP PV OF MOTIONS PROPER 53.90 . a yr mas 0 0. ′′ 1toward 11 53.85 ◦ 1997.03 o 075)i hw ntebto etcre fteimages. the of corner left bottom the in shown is 2007.50) for − 1 ; 53.80 20 4554.10 o D207 a efudi uorn tal. et Ducourant in found motion be proper can entire (2005) reported 200775 the recent HD of most motion providefor The proper should the motion of cluster. cen- proper estimate its its good near and very a mass, be to of likely ter is 200775 HD cluster, pnil o oto h luiaino G 7023 re- NGC star of bright illumination the the published (see degrees of 200775, reliable most few for HD found sponsible a we is which within motions for proper star Cep) only 7023 PV NGC the of of star indeed, of only motion The (and motion proper 7023. the NGC proper with within above the stars derived compare Cep must PV of one 7023, NGC eycoet h trsnetegsdniytypically density gas the since as located star falls is the which to wind, close the very in gas density highest the ih emvn at moving be might ue eecnsfl easmdt ersn the represent to assumed Cep. PV be mea- of safely motion motions Rodr´ıguez, & can (Loinard, proper here N the Tau sured T Thus, of or Pech 2003). Rodr´ıguez 2007; 2010) al. al. et et (Loinard observa- 16293-2422 can multi-epoch IRAS the themselves of from tions motions instance, for stellar seen, the young be trace from can emission free-free stars of observations VLA in o VCp oee,tervle of values their However, Cep. PV for tions 10 ots h rpslo A04ta VCep PV that GA2004 of proposal the test To ned uorn ta.(05 lorpr rprmo- proper report also (2005) al. et Ducourant Indeed, § 10 ) ic ti h rgts ebro the of member brightest the is it Since 1). n hygive they ; ( 54.05 r ) e emfrec pc (0. epoch each for beam zed ∝ r 54.00 − RIGHT ASCENSION(J2000) 2 h ihacrc ihwhich with accuracy high The . .RESULTS 4. µ α 53.95 ∼ cos δ are 2k s km 22 +11 = 53.90 − ,3 ,5 ,7 ,10, 8, 7, 6, 5, 4, 3, 3, 53.85 − ± ′′ 2007.50 48 1 s ak the marks oss a yr mas 2 × wyfrom away µ 53.80 0. α ′′ 8;PA ; 28 cos δ − 1 = ; © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México agrerr hnormeasurements. our than errors larger tv eoiyo 0k s km 40 of velocity ative cnroasmn on pe f1 ms km 10 of speed sound a assuming scenario − µ 380 andi h ipro aao,weetereported the are where motions catalog, proper Hipparcos the in tained eddwr oiga 2k s em- km is Cep 22 PV at which moving in PV proposed were cloud by model gas bedded driven the the if by jet GA2004 explained the by be of still surround- morphology could its The Cep to relative speed gas. that ing at moving be to µ ealta A04peitdarltv eoiyof velocity s relative km a 22 predicted GA2004 that Recall tv rprmto ams nieyi ih ascen- right ∆( in of entirely sion) (almost motion proper ative ftevle utdb uorn ta.(05 are obtain: we (2005) figures, al. Hipparcos et the Ducourant Using by used. quoted values the if o eur VCpt emvn wyfrom away moving be s to km 22 Cep at 7023 PV NGC require not nieyt aebe jce rmNC72 about 7023 NGC from ejected 10 been have to Cep unlikely PV of motion marginal ward Hippar- a the suggests anything, value If cos right in declination. both and 7023 ascension NGC to relative stationary nearly diction, ossetwt n nte tte1 the at another one with consistent oino VCpmaue bv rmta of that from proper above measured the is Cep 7023) subtracting NGC PV by of (obtained motion 7023 NGC ausaeicnitn tte3 the at inconsistent are values δ δ 3 11 5 ± = titysekn,teaayi fG20 does GA2004 of analysis the speaking, Strictly h eaiemto ewe VCpand Cep PV between motion relative The hyae fcus,ee oeicnitn ihterel- the with inconsistent more even course, of are, They +2 = rago. yr a yr mas 7 G 03 ecnld htP e svery is Cep PV that conclude We 7023. NGC ∆( ∆( − 11 1 − µ µ . 48 1 α α ± n hwta VCpi nfc very fact in is Cep PV that show and µ ∆( ∆( oadtews,crepnigt rel- a to corresponding west, the toward cos cos ± α − a yr mas 2 1 cos µ µ 0 ; δ δ δ δ . µ = ) +0 = ) 4msyr mas 54 = ) +1 = ) δ δ +9 = ) = 970 20 1997.03 075 20 2007.50 µ Epoch − − α − − 4 1 cos − 14 − 1 . . . . 2 1 1 7 8 1 bandi h eahdclump detached the in obtained ± D207 sas con- also is 200775 HD . tol eursP Cep PV requires only It . ± ± . ± ± δ a yr mas 3 − a yr mas 7 +6 = 3 3 1 2 1 OIIN N LXDNIISFRP CEP PV FOR DENSITIES FLUX AND POSITIONS . . hs w ausare values two These . . . a yr mas 1 a yr mas 6 a yr mas 9 a yr mas 7 h h σ 45 45 . − ee ihti pre- this with level 74 m m − 1 − 53. 53. 1 ± α 1 . oadteeast the toward 5 h observed The . (J2000) aesignificantly have − s s 0 − − σ − − 9449 9651 1 . 1 1 4msyr mas 64 1 1 level. (see , , . , ± ± § 0. 0. ONR TAL. ET LOINARD 2.1). s s 0167 0051 0467 0014 oiin36c Flux cm 3.6 Position − to- AL 2 TABLE 1 ; ◦ ◦ 57 57 os hsi aeitreit ewe h two the between intermediate case a is This mass- enhanced jet, loss. of low- underlying episodes steady, rate) undergoing a mass-loss periodically moderate consider (i.e., should level one situation, that i aelkl encetddrn psdso signifi- of mass-loss. episodes increased the during cantly analy- created but been bisector likely system, their have A in the sis GA2004 in by present strong considered clearly knots therein). of is signs references jet clear steady and show (GA2004, does Cep variability PV by driven in flow continuous a such of sidewind. al. terms a (L´opez et in Cant´o 30 by (1995) HH interpreted Raga by was & driven shape curved jet whose the relevance 1995) of particular case Of the morphologies flows. is curved stellar the young other explain of to used been wouldhave in presented velocity astrometry relative the § small with consistent a fully such be and a of data, 7023 tor NGC s and km Cep few PV between velocity ative eaiet ohP e n G 03 econ- We in because 7023. mentioned however, as NGC unlikely, (i) very and possibility Cep this PV sider both to relative tr htfre ihnit. within formed that stars ns ol ceeaea niemlclrcodto mech- cloud physical molecular s km what entire 22 an clear accelerate not could is anism it very (ii) are Cep and PV with similar, and 7023 NGC with associated oatetetbsdo h yohsso tayjet. steady a of hypothesis naturally the more itself on lend based does treatment and a Cep, to PV in that than uous entv osblt spoie ytecontinuous al- the in obvious presented by One model pairs provided jet Cep. HH is PV successive possibility by of ternative driven flow bisectors the the along of east- shift systematic the ward be of interpretation to different must a one appears seek observations, surroundings present the its with and inconsistent Cep PV tween ′ ′ 12 38. 38. .W oe ned htcniuu e models jet continuous that indeed, note, We 3. δ J00 est (mJy) Density (J2000) ti motn ont,hwvr htteflow the that however, note, to important is It ie htarltv eoiyo 2k s km 22 of velocity relative a that Given oeta h o nH 0apasoealmr contin- more overall appears 30 HH in flow the that Note ′′ ′′ 680 682 − ± ± − 1 atclrywtotas ceeaigthe accelerating also without particularly , 1 0. 0. ′′ ′′ ol esffiin oepantebisec- the explain to sufficient be would 1 0 017 0 0 008 .DISCUSSION 5. § ,terda eoiiso h gas the of velocities radial the 1, . . 14 18 § ..I htseai,arel- a scenario, that In 2.2. ± ± 12 0 0 . . 02 01 ocmltl describe completely To − 1 be- © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México daie ecitospoie in provided descriptions idealized n t urudnso tlat2 ms km 20 least at of Cep surroundings PV jet. its between continuous velocity and relative a case a of the situation, that this to to In than similar bullets more detached certainly of specific almost that for is description source particu- mass-loss correct seem the periodic strong, Cep larly the PV by since it undergone However, treat enhancements to needed general. be in principle in would simulations ln h e rvnb VCp H35A ,and B, A, 315 HH Cep: PV by driven jet the along GA2004? of origin results the bisector at Cep be PV 16293-2422 the IRAS of in asymmetry that an to Could similar extended counterpart. more southern times its 1.5 than and about massive lobe more (e.g., northern times a asymmetric 2.5 with equally 2002a) be Goodman to & Arce happens outflow Cep PV molecular south- in the Interestingly, its that equivalent. extended ern more much and being Hi- lobe massive, 2001; northern conspicuous, the al. 2001), to et known al. Castets et is rano (e.g., system asymmetric jet highly that molecu- be by large-scale powered the particularly outflow addition, 2010, lar In al. 2). et Figure (Pech their position source the driving through the pass line of not the does observations– ejecta the of the one joining clump least northern at the –in of that that and than two larger is clump times southern three the to of shown speed central have projected the the observations that from radio away Multi-epoch AU moved now 60 source. has about clump each projection) and ejected (in ago, In been years has few clumps 2010). a of just pair bipolar al. low-mass a et young object, (Pech very this the 16293-2422 of IRAS that protostar is case Arguably clearest asymmetries. the of are kind 2006) this exhibit al. to Mart´ı,known et 2000; Curiel 1–2, the al. 1998; Rodr´ıguez et HH Reipurth of 80; Rodr´ıguez, & HH (e.g., density or jets the A, Several in asymmetry material. an circumstellar of mechanism an because launching of jet or the because in either not asymmetry directions, intrinsic and/or opposite speeds different in of at exactly sides away two moved the on star ejecta the the pairs if would however, ejecta assumption violated, such This be of source. bisectors driving the the that intercept sta- it, way a a from such away from in symmetrically ejected propagate clumps star of tionary pairs of that argumentation is the asymmetries. GA2004 behind invoke assumption to basic be The would GA2004 of results new our with inconsistent be to GA2004, measurements. appears of results that bisector the and explain to needed be he ar fH rushv enidentified been have groups HH of pairs Three bisector the of interpretation alternative Another § ,s numerical so 2, RPRMTOSO VCP381 CEP PV OF MOTIONS PROPER − 1 would ntesraeo oeo pnn angle opening of cone a of precesses surface axis Hjellming jet the the (e.g., on that model assumes 1981) This Johnston re- & is 3a. and Figure (1997) structure in al. G´omezproduced that jet et by for proposed precessing been accounts simple has reasonably A the that in 3). model precession (Figure dis- jet from not underlying resulting S-shaped an are clearly along but groups Goodman structure, line, HH straight & a these Arce along tributed Moreover, GA2004; 1997; 2002a). created been al. have accretion/ejection et (G´omez enhanced to of believed episodes are three see during They 1997, F and al. 3). G´omez E, et Figure D, (e.g., 315 south-east HH the and toward north-west, the towards C ω ya angle an by osateeto velocity ejection constant h lc ieo iue3 orsod to corresponds 3a Figure on line black The i φ n h otenhl ftejtpeessaround precesses jet jet, 10 the northern by of misaligned the axis of half an that southern than the larger southern south- and 10% the the is of jet for velocity part ern different the northern slightly Specifically, the but counterpart. for flow, (1997) to the identical al. of model an G´omez a et As 3b of Figure jet. that in the show of we symmetry example, improved the significantly slightly be do relaxing driving can E by the situation to of The B position and current source. the F through to pass C not HH joining the segments of the distribution the Be- groups, in asymmetry GA2004. the of of re- cause conclusions of A way bisector different the course, a yr. Of expressing simply is 1000 pair. inconsistency B-E about age the this by for differing occurs as- situation ages would similar 3a them Figure to in cribe shown been model have symmetric episode, to mass-loss the enhanced expected same is the during pair created C-F in- For the 3a. while Figure stance, in apparent immediately is groups PV years. in 2000 every occurred roughly mass-loss succes- Cep enhanced that of shows episodes model sive this (1997), al. G´omez et gs40 rad60 raevr erycoincident nearly very are at yr bisectors 6900 the and particular, yr 4900 In ages considered. jet larger are as the east ages of the sides towards displaced either groups progressively on F are positions and same-age joining C segments of the of B pairs bisector to the the Moreover, and to yr) yr). age (6900 (4900 same south- groups the the represents E ascribes of and model and positions groups, a the HH to Such ern fit better jet. somewhat northern a the of axis 80 = n h oiinageo h rcsinai is axis precession the of angle position the and , = naymtyi h itiuino h HH the of distribution the in asymmetry An − ◦ 36 , ω . 5 ◦ 1 = Go e ta.19) sdsusdby discussed As 1997). al. (G´omez et i . rmteln fsgt h e has jet The sight. of line the from rmnyr arcmin 5 ◦ v eaiet h symmetry the to relative − e 1 n rcsinvelocity precession and , v 8 ms km 180 = θ θ inclined , 22 = − 1 and , . 5 φ ◦ . , © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México asv oeua a hl,weesn entrained no entrain whereas to shell, known gas is molecular north) For massive the asymmetric. a (to quite C be knot to instance, likely PV surrounding is gas however, would the Cep, model of asymmetric distribution the The our not suggest. as and lobe around, northern way the other than southern slower the be expect Good- to might & lobe one (Arce Thus, denser it of significantly 2002a,b). north man be immediately to gas appears the than Cep PV of GA2004. south by Cep PV in found re- those domain bisector to what produce similar can in sults they know space to parameter useful the of be would par- it In ticular, surroundings. bipolar asymmetric of encountering in- models jets to numerical interesting realistic be would more It vestigate for velocity. need no stellar with large GA2004 ex- a of readily results could of bisector and structure the one, plain the symmetric a of than description flow the better does a It provide unique. jet not can asymmetric slightly clearly a of is that and however, structure demonstrate, Cep, true PV in the jet of the oversimplification an sents pairs C-F and 3b). B-E (Figure the of bisectors measured the with intercep squares). They red shown. and are blue yr as 6900 (shown and give pairs 4900 parameters j at C-F the jet the and with the along jet along positions precessing al positions asymmetric G´omez expected posit expected et an The following the on F. joining jet based and Lines precessing Model E, to symmetric D, line). groups are a black three south-east on The (solid the based Cep. toward PV groups Model around three (a) knots the HH and of C, groups and of Distribution 3. Fig. 382 ti ot etoigta h a immediately gas the that mentioning worth is It repre- certainly 3b Figure in shown model The ONR TAL. ET LOINARD t urudns n sntafs-oigrunaway fast-moving a not is to shows and respect measurement with surroundings, stationary This its essentially is of Cep Cep. PV motion PV that proper star the young measured the have we years, 10.5 etgt ueial nwa ido iuto they develop. situation to of tend in- kind in would to what effects and in not) these numerically or vestigate for certainly (symmetric It search systems outflow Cep. to other PV relation worthwhile in direct jet be a the would have of they asymmetry if sys- the unclear outflow two to is other These it in wiggling and scales. reported the tems, small been is at not second located have seen The effects jet gas southern Cep. red-shifted the PV of of of tail east one a the first of The to existence star. runaway the a idea is be the might supporting Cep PV evidence that of pieces two mention Cep. it. PV of of surroundings south immediate distribution that the density higher the material in to be compared molecular reversed might is of Cep This density PV that, of the suggests north scales, This large 2002a,b). on Goodman knot counterpart & southern (Arce its F with associated is gas oprn w L bevtossprtdby separated observations VLA two Comparing nadto oterbsco eut,GA2004 results, bisector their to addition In ta ie 00 00 n 00y r hw.(b) shown. are yr 8000 and 7000, 6000, times at et ntetx sldbakln) ie onn the joining Lines line). black (solid text the in n 19)wt h aaeesgvni h text the in given parameters the with (1997) . h oiin ftebscoso h B-E the of bisectors the of positions the t osaetknfo ´mze l (1997). al. G´omez et from taken are ions ad h ot-etaelble ,B, A, labelled are north-west the wards .CONCLUSIONS 6. © Copyright 2010: Instituto de Astronomía, Universidad Nacional Autónoma de México etrG re eateto srnm,Yl nvriy ..Bx20810 Box P.O. University, Yale Astronomy, of Department Arce: G. Hector lsaA oda:HradSihoinCne o srpyis 0Gar 60 Astrophysics, for Center Harvard-Smithsonian Goodman: A. Alyssa ljnr .Rg:Isiuod inisNcers nvria ainlAut´ono Nacional Universidad Nucleares, Ciencias de Instituto Raga: C. Alejandro Galv´an-Madrid, R., F. Rodr´ıguez, L. & P., T. Ray, R., Mundt, Eisl¨offel, J., Lecampion, P., P´eri´e, J. R., 878 Teixeira, A. 638, C., ApJ, E. 2006, Ducourant, Harlan, al. & et S., H., Curiel, Spinrad, & V., E., L. Caux, Kuhi, L., M., Cohen, Loinard, C., Ceccarelli, A., F. Castets, Rodr´ıguez, L. & L., 1120 Loinard, 277, C., MNRAS, A. 1995, Raga, Cant´o, C. J., A. Raga, & Cant´o, J., og ato nttt eAtoo´a nvria ainlAut´onom Nacional Astrof Astronom´ıa, Universidad de Cant´o: Instituto Jorge y Radiostronom´ıa de Centro Rodr´ıguez: F. Luis and Loinard Laurent re .G,&Gomn .A 02,AJ 7,928 575, ApJ, 2002a, A. A. Goodman, & G., H. 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