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

Fierro, C. R.; Peimbert, A.; Georgiev, L.; Morisset, C.; Arrieta, A. NGC 6826: A UNIFIED STUDY OF THE PLANETARY NEBULA AND ITS CENTRAL STARS Revista Mexicana de Astronomía y Astrofísica, vol. 40, 2011, pp. 167-168 Instituto de Astronomía Distrito Federal, México

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Torres-Peimbert eMxA(ei eConferencias) de (Serie RevMexAA oad ´xc,Ad.Psa 024 41,M´exico, D.F., 04510, (crfi[email protected]). 70-264, Mexico Postal M´exico, Apdo. de noma aatcpaeaynbl G 86 nfidmdlrqirsmr ok u t uncertai its but work, more constraints. requieres observational Words: of Key model number Dista unified methodol larger A This their model. to 6826. nebulae. self-consistent due NGC planetary of stellar-nebular nebula stars planetary a central galactic obtain of tracks to evolutive methodology theoretical a present We observacionales. restricciones n´umero de mayor unifica al modelo debido El incertidumbres 6826. las gal´actica NGC disminuye autocons planetaria nebulosa estelar-nebular central estrellas te´oricas la modelo evolutivas metodolog´ıa de a trazas esta un las usando obtener distancia para la namos trabajo metodolog´ıa de una Presentamos o n nemdaems tr 08t 8.0 to (0.8 stars mass intermediate and low e . 11,Meio .. Mexico. Santa M´exico, D.F., de 01210, Lomas C.P 880, Fe, Reforma la de Prolongaci´on Paseo cana, xtetmeaueo Bi nytenme of number the only to is criterion BB The a of temperature models. bod- the atmosphere black fix or are (BB) models photoionization ies in used ally the pa- different of with examples literature two rameters. the to shows from distance 1 models the Table stellar in uncertainty objects. biggest high The these the star. is same repro- the problem can of observations galactic model the of one duce (CSPN) than stars more central nebulae, of planetary case the in that, oe ftepaeaynbl n t eta star. central its and star. nebula central planetary its the self-consistent of with a obtain model nebula to methodology the a com- present of We that study works the few developed bine are been there have however, stars (CSPN) separately; central nebulae or gas. PNe planetary surrounding either of the of enough ionize models hot detailed to Many is able photons remnant emit stellar the to of the nucleus the star, surrounding progenitor gas of shells are They G 86 NFE TD FTEPAEAYNBL N ITS AND NEBULA PLANETARY THE OF STUDY UNIFIED A 6826: NGC 1 2 lntr eua Pe r h nlsaeof stage final the are (PNe) nebulae Planetary nteohrhn,teinzto ore gener- sources ionization the hand, other the On note we literature the in published data the From nttt eAtoo´a nvria ainlAut´o- Nacional Universidad Astronom´ıa, de Instituto et.d ´sc ae´tcs nvria Iberoameri- Matem´aticas, F´ısica Universidad y de Depto. .NE FAUIIDMODEL UNIFIED A OF NEED 2. tr:rtto tr:wns outflows winds, abund stars: stars: — — rotation 6826) (NGC stars: individual — nebulae: planetary — abundances ISM: .INTRODUCTION 1. .R Fierro, R. C. 1 .Peimbert, A. , 40 6–6 (2011) 167–168 , ETA STARS CENTRAL 1 M .Georgiev, L. ABSTRACT ⊙ RESUMEN ). tdwt h id h eua oe epnsto responds model nebular The in changes wind. associ- the profiles the with P-Cygni ated reproduce including should spectrum, model to photoion- CS stellar is the The PN) to and input model. as (CS ization model objects atmosphere two the the use link 2009). to Georgiev way & (Morisset One parameters PN and CS param- different with literature eters. nebu- the of from examples models two shows lar 1 Table neb- the spectrum. in observations ular the reproduce The to models studies. ular nebula. neb- these several the in allows distance-luminosity in considered degeneration not ionization is of wind state Stellar the reproduce to oe sue,sm aaeesaeaotdfrom adopted are parameters while sources, some atmosphere other an used, When is gas. model of nebular state the the in reproduce ionization to necessary photons ionizing ayohr aaees eas fti problem, this of in because luminosity- degenerations parameters; The others produces many degeneration problem. absolute the difficult distance of a determination luminosity the making known, parameters. the in possible uncertainties the of and number models the observational reduce additional imposed, the nebular constraints or but stellar separately; a model requires producing over model work stellar-nebular additional A degree. ionization .LMNST-ITNEDEGENERATION LUMINOSITY-DISTANCE 3. 1 hr r e tde htsmlaeul tthe fit simultaneously that studies few are There h itne oteGlci N r poorly are PNe Galactic the to distances The .Morisset, C. T eff n uioiyo h trcagn its changing star the of luminosity and sd euoa lntra.S aplic´o Se planetarias. nebulosas de es 1 n .Arrieta A. and T eff g sapidt td fthe of study to applied is ogy orqir ´staaopero m´as trabajo requiere do n uioiyaechanged are luminosity and ne tr:atmospheres stars: — ances c sdtrie using determined is nce 2 set.Determi- istente. te r smaller are nties 167 © 2011: Instituto de Astronomía, UNAM - XIII Latin American Regional IAU Meeting Ed. W. J. Henney & S. Torres-Peimbert eea oeswt ieetcmiain nteval- of the ues in combinations different with models several 168 etyaet h ie( size the affects rectly n orecnrpoueteobservations. the ioniz- reproduce the can of source ing temperature of Pho- and combinations luminosity, gas. different emitting distance, with of volume models the toionization as well as nebula, ai ftesm lmn ntosbeun stages subsequent two C in (e.g., element ionization of same the of ratio 19)i ojnto ihtednmcaeo the of age Wood dynamic & the Vassilidis with nebula. of conjunction tracks in evolutive (1994) distance the the in used uncertainty dis- reduce we the to is order parameter In critical tance. the nebula the and star itne eotie nuprlmtt h dy- the to assuming by limit yr upper 30150 given of an age a obtained namic from for We known observations, is in distance. age velocity dynamic expansion The the range. distance a and h yai g a xdi 70y assuming yr 3700 in fixed was d age dynamic the osbesltosaei h eindlmtdby delimited (1994). region Wood the in & are Vassiliadis solutions use of Possible We tracks tracks. evolutive evolutive the in the it locate to possible is n yai g ag.Eeypitwti hsre- luminosity, this of within combination point a Every represent gion range. age dynamic and e orpouetesaeo oiaino h nebula. the of or- ionization in of state models the photoionization reproduce to to models der input that These as those used spectra. were selecting observed the CS, Several reproduce for best tracks. obtained evolutive were the on models delimited area the distance a obtain model. we studied the data each velocity available for expansion the as of Assuming average age. dynamic hswr selrnblrmdl 45.0 model) (stellar-nebular work This urtk ta.20 selrmdl 6038 .410 128 158 1200 1200 7.94 18.0 3.80 3.90 46.0 50.0 44.0 model) (nebular 1998 Henry model) & (stellar Kwitter 2006 al. model) et (stellar Kudritzki 2004 al. et Pauldrach uedrnt otsh20 nblrmdl 753.75 47.5 model) (nebular 2008 Pottasch & Surendiranath min nteohrhn,acag ntedsac di- distance the in change a hand, other the On The the of parameters the in degeneracy the solve To itne eotdi h ieauehl oset to help literature the in reported Distances nwn h yai g n eprtr fCS of temperature and age dynamic the Knowing eea osbesltoswr xlrdwithin explored were solutions possible Several v 0 = ( L .BEKN H DEGENERACY THE BREAKING 4. exp T , . p and kpc 7 eff R ) min and , fteC a ecntanduigaline a using constrained be can CS the of 0k s km 10 = M Reference v a erdc h observations. the reproduce can IV ( exp R λ ) 1169/C in max − , 1 R h oe ii to limit lower The . 8k s km 18 = out III sue o the for assumed ) d λ max 16ratio). 1176 AAEESO G 6826 NGC OF PARAMETERS − 3 = 1 . T . eff 8kpc 18 k)(10 (kK) IROE AL. ET FIERRO T and , eff ± T . 3.65 2.5 eff AL 1 TABLE log · · · · · · · · · ± aslai,E,&Wo,P .19,AJ,9,125 92, ApJS, 1994, R. P. Wood, 483, & A&A, E., Vassiliadis, 2008, S.R., Pottasch, & H. R., M´endez, R. & Surendiranath, L., T. 1517 Hoffman, 247 507, A., 493, A&A, W. ApJ, 2009, A. 1998, L. Pauldrach, C. Georgiev, B. & R. C., Henry, Morisset, & B., K. Kwitter, IAU 2006, J. Plus, & A., M. Urbaneja, P., R. Kudritzki, ASP 2005, J., A. Sauval, & N., Greveese, M., Asplund, Mexico). (UNAM, DGAPA from IN123309 PAPIIT from taken was (2005). presented al. value et solar Asplund the The within agree abundances errors. carbon, nebular of and exception stellar the parameters the With with additional work. this shows compared in 2 obtained 6826 Table NGC works. of others model preliminary a model. self-consistent stellar-nebular a yields This 8.60 O 8.18 N Rotational e11.04 He 8.00 C g 5000 Age R g . 1.50 0.2 DIINLPRMTR O G 6826 NGC FOR PARAMETERS ADDITIONAL neb 519 1111 419, A&A, 2004, M´endez 119 (Cambridge: H. Press), R. Univ. & Cambridge Barlow Be- J. and M. Galaxy ed. our yond, in Nebulae 25 Planetary 234, ASP), G. Francisco: Symp. (San T. Bash N. ed. of F. & Nucleosynthesis, Records III as and Barnes Abundances Evolution Cosmic Stellar 336, Ser. Conf. hswr a atal upre ytegrant the by supported partially was work This from obtained parameters some presents 1 Table − 8 v M · · · · · · v M × ˙ ⊙ ± sin 1100 1 yr − REFERENCES i 1 k s (km ) .RESULTS 5. AL 2 TABLE tla eua Solar Nebular Stellar ± ± ± ± ∞ ± .08.50 0.30 .07.95 0.30 .511.03 0.15 .08.80 0.30 − 0 6000 100 1 (kpc) ) 70 0 . ± 07 186200 L/L 5k s km 15 601.40 1640 ± ± ± 22.60 3.18 82 48 ⊙ 0 0.80 500 00yr 1000 0 . ± ± ± ± 1pc 01 .08.60 0.30 .07.78 0.30 .510.93 0.15 .08.30 0.30 − Distance 1 · · · ± 0.2