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Stellar Evolution in the Galactic Bulge J.A on the UK Schmidt telescope. FLAIR4 is a fibre-fed spectrograph which will be able to obtaln spectra of up to 100 ob- jects per exposure down to B = 18.5 and agreement has been reached to rlde piggy-back on another programme working at the SGP. The remaining 235 candidates in this magnitude range In the ottler selected fields would need to be observed with the 2,2-m, 3.6-m or Nl-r, In addition, experience from the EMSS follow-up has shown that often more than one stellar object with a reasonable favratio is associated wlth one X-ray source. The secondary crite- rion for stellar X-ray idmtlfication Is the presence of chromospheric emksion rn llnes or rotatlonally broadened absorp- tion lines In the spectrum of the star. This wlll require higher-resolution spec- trampy particularly for RS CVn and W UMa blneries and solar-type stars wlth moderate levels of chromospheric activity. Therefore, towards the end of the survey this type of spectroscopic work will be necessary far an estlrnated 250 stars. I All members of our team feel that it is important to allow time for follow-up obsewations of Important, exciting, in- "gUr8 3- teresting or new objects as soon as specifically to meet the requirements of allow team members to profit better possible. We have therefore requested idenmcation, an extra allocation be from the somewhat arduous tasks d that, contiguous with the time allotted made to allow for follow-up. This will survey identification. PROFILE OF A KEY PROGRAMME Stellar Evolution in the Galactic Bulge J.A. BLOMMAERJ, A.G. BROWN, U.J. HABING, J. LUB, Y.K. NG,R.S. LE POOLE, P. T. DE ZEEU W, Sterre wacht Leiden, the Netherlands G. BERTEL LI, A. BRESSAN, C. CHIOSI, Osservatorio As tronomico, Padova, Italy W.E.C. J. VAN DER VEEN, Columbia University, New York, USA H. E. SCH WARZ, ESQ M. W. FHST, South African Astronomical Obsewatory, Cape Town, South Africa targe-scale maps at infrared wave- Some parts of the Galactic Bulge out- Plaut's painstaking work by measuring lengths obtained with IRAS and COBE side the galactic plane can be studled B and R Schmidt plates with an automa- show our Milky Way as an edge-on spi- optically, In particular, there is a 65 by tic measuring machine, and using a ral galaxy, and clearly reveal the Galac- 6:5 field (900 pc by 900 pc) of low and photo-electric callbration sequence. He tic Bulge. This separate component of homogeneous extlnctkn, centred at obtained more accurate magnitudes, our Galaxy can be considered as the I = O0, b = -1V, which in the rnid-fif- and confirmed Plaut's list of variable nearest ellipsoidal stellar system. ties was chosen by Baade and Plaut as stars. As a result, nearly all Miras, Long- Studies of its stellar content are crucial a good field to search for variable stars Period Variables, Semi-Regular Vari- not only for our understanding of stellar by photographic techniques (cf. Blaauw, ables, and also the RR Lyrae stars have evolution and stellar populations in gen- 1955). It is often referred to as the now been identified. Accurate perlods erat, but also for calibrating the rnea- Palomar-Groningen Field Nr. 3, or sim- and light curves have been determined surernents of the cotours and line ply as the Baade-Plaut field. Its location for all stars with periods less than 300 strengths of the integrated light of ellipti- IS illustrated in Figure 1. Recently, days. We are extending Wesselink's cal galaxies (Whitford, 1986). Wesselink (1987) has repeated part of work, with the aim of constructing a 7Re Bulge of our Galaxy (ESO phtqm@h8 1986, Mwm€~er,4@14-75), The phofogreph camappmxlmtely 80 by 45 degree~f.The Baade-Plaut neld Is indicated by the ccashed square. T-p's dew CCD phohmtiy fieids are denow by astahk fhe dpen drcleg am BQmand TBmdn@s (1-1 sumy Wds W late-type glmts. The didreetanQle indIcete~the central W studied h the IR by Catchpole et a/. (1NO). 14aa&'s Windows: NGC 65ZP,Sgr I end Sgr 11. Hertzsprung-Russdl diagram for a sam- the evolution of these late-type stars. Do the ESO Schmidt telescope - centred ple of mow than one million stars In the Miras evolve Into IR stars by an incraas- around the prominent Ha or [0111] emis- Saade-Plaut field. This Is done by Ing mass loss or do these two groups sbn lines - with available continuum UK means of automated photographic pho- repremt late-lype stars wlth different Schmidt R plates. tometry (in U, B, R, I) which yields mag- masses and therefore differed We expect to obtain many objects in nitudes and colours to an accuracy of lumlnosltles? It has always been dlfflcult all phases of the AGB evolution, so that 0.03 mag. Because the number of stars to distinguish between these two a comparison of the relative numbers is so large, we expect that even "fast" scenarios as dlstanms and therefore will yield the duration of each phase, evolutionary phases will be well rep- lumjnmities generally are uncertain. including the fast ones. The results will resented. The Baade-Plaut fleld is Weal for a be analysed using state-of-the-art &I- The evolution of low and Intermediate study of the late and luminous stages of lar ewrlutlonary tracks. This should allow mass stars (1-8 MQ) ultimately leads to stellar evolution in the Galactic Bulge. a precise delineation of the link between the Asymptotic Giant Branch phase Ail the objects are at abwt the same Mlras, Long-Period Variables, Smi- (AGB), which is followed by the forma- distance, and many of the AGB stars Regular Variables and OWTR stars, and tion of a planetary nebula. Miand have been found already through a derivation of an accurate period- OH/IR stars are situated at the top of the Wessellnk's work. In ddltion, we have a luminosity relation. The direct relation AGB. Thy are very luminous, long sample of candidate IR stars selected between mass-losing giant stars and perlodlc, mass-losing variables: M tras from the lRAS Point Source Catalogue planetary nebulae can be established have periods up to 500 days, while IR by means of the F25F 12 dux ratio crite- independent of distance-scale related stars have even larger periods. During rion (cf. Whitdock et al., 1986). We are problems. this phase the stars enshroud thm- carrying out near-infrared photometry We are taklng optlcal spectra of many selves In a clrcumstellar gaddust shell. on these objects to Investigate the na- of the Mira's, from which we hope to General scenarios for AGB evolution are ture of the IRA$ sources, and to deter- derive their metallicities, so that we can available (e.g., van der Veen 1989), but mine the bolomebic luminosities of the address the luminosity/metal abun- much more quantitative work has to be AGB stars (cf. Whitetock et al,, 1990). dance differentiation. The spectra wlll done and several details have to be When repeated wMciently often, such also provide radial vejocitles, thus shed- cleared up. In particular, at present it is measurements will also give the pulsa- dlng Ilght on the dynamics of the Bulge. Unclear whether or not there Is Increas- tlonal period of the star. Finally, we will The mix of stellar objects as a function ing mass loss on the upper AGE, and 1f also search for planetmy nebulae by of galactic latitude (or mMlicity) can be there is, what consequences this has for comparing narrow band exposures with determined, In particular when our study of the Baade-Plaut field is combined vide information on the history of the Temdrup, D.M., 1988. Astron. J., 98,884. with similar studies of other Bulge fields, Bulge. van der Vm, W.E.C.J., 1989. Astron. As- such as Baade's window (Terndmp, troph., 210, 1&. 1988; Rlch, 1989). and the central region References Wesseflnk, T., 1887. A ~~tr(cShrdy of (Catchpole et at., 1990). This is impor- Blaaw, A,, 1955. 1AU Sympodurn No. 1, Variable stars in a field nwthe Gelactk CenW, PhD the&, Unlvemity of Nljmegen. tant also for the understanding of the Coordination of Galactic Rasearch (Cam- Mdge University Press). Whltelock, PA, Feast, M. and Catchpole, stellar composition of the bulges of R.M., 1986. MmNdt. R. Astt. See., m,1. other galaxies. Bl-, V.M., and Terndrup, D.M., 1989. As- tmJ., 08, 843. Whitelock, PA, Feast, M., and Catchpole, In summary,this Key Project aims at Catchpole, R.M., Whitel&, PA, Glass, 1.S.. R.M., 1490. Mon. htR, Ask SQC., In Improvlng our understanding of stellar 1-0. Mon. Not. R. Astr. Soe., In preas. PW. evolution on the AGE by a compre- Rich, R,M., 1989. In IAU Symposium No. 136. Whltfwd, A.E., 1986. Ann Rev. Astron. AS- hensive study of the Baade-Plaut field The Center of the Galaxy, ed. M. Mms troph., 24, 19. in the Galactic Bulge. Thisa will pro- (Dordrmht: Kluwar), p. 63. PROFILE OF A KEY PROGRAMME Kinematics of the Local Universe G. PA TUREL ', L. BOTTINELLI~,P. FOUQU~', R. GARNIERI, L. GOUGUENHEIM~, P. TEERIKORPl3 'Observatoire de Lyon, Saint-Genis Laval, France 'ERA D, Observatoire de Paris-Meudon, Meudon, France 3Turku University Observatory, Tuorla, Finland Introduction of our necessarily subjective point of examples: the location, first discovered view and the subtle biases which affect by H, Shapley (1) from the asymmetry of How matter is organized in the Uni- this description. Historical evidence the dlstributlon of globular clusters, was verse is a fascinating problem to solve shows that understanding the determi- accepted only when dynamical argu- because it imposes severe constraints nation of the velocity field is of funda- ments were glven by J.H.
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