Binary Stars as Critical Tools & Tests in Contemporary Astrophysics Proceedings IAU Symposium No. 240, 2006 (cid:1)c 2007InternationalAstronomicalUnion W.I. Hartkopf, E.F. Guinan & P. Harmanec, eds. doi:10.1017/S1743921307003730 Introduction & Overview to Symposium 240: Binary Stars as Critical Tools and Tests in Contemporary Astrophysics Edward F. Guinan1, Petr Harmanec2 and William Hartkopf3 1Department of Astronomy & Astrophysics, Villanova University, Villanova, PA, 19085, USA e-mail: [email protected] 2Astronomical Institute of the Academy of Sciences of the Czech Republic, 251 65 Ondrejov, Czech Republic 3Astrometry Dept., U.S. Naval Observatory, Washington, DC, 20392, USA Abstract. An overview is presented of the many new and exciting developments in binary and multiple star studies that were discussed at IAU Symposium 240. Impacts on binary and multiple star studies from new technologies, techniques, instruments, missions and theory are highlighted. It is crucial to study binary and multiple stars because the vast majority of stars (>60%) in our Galaxy and in other galaxies consist, not of single stars, but of double and multiple star systems. To understand galaxies we need to understand stars, but since most are members of binary and multiple star systems, we need to study and understand binary stars. Themajoradvancesintechnology,instrumentation,computers,andtheoryhaverevolutionized whatweknow(andalsodon’tknow)aboutbinaryandmultiplestarsystems.Datanowavailable from interferometry (with milliarcsecond [mas] and sub-mas precisions), high-precision radial velocities (∼1-2 m/s) and high precision photometry (<1–2 milli-mag) as well as the wealth of new data that are pouring in from panoramic optical and infrared surveys (e.g., >10,000 new binariesfoundsince1995),haveledtoarenaissanceinbinarystarandmultiplestarstudies.For example, advances have lead to the discovery of new classes of binary systems with planet and brown dwarf components (over 200 systems). Also, extremely valuable data about binary stars areavailableacrosstheentireelectromagneticspectrum—fromgamma-raytoIRspacemissions andfromthegroundusingincreasinglymorepowerfulandplentifulopticalandradiotelescopes aswellasrobotictelescopes.Intheimmediatefuture,spectralcoveragecouldevenbeextended beyond the radio to the first detection of gravity waves from interacting close binaries. Also, boththequalityandquantityofdatanowavailable onbinaryandmultiple starsaremakingit possible to gain unprecedented new insights into the structure, and formation and evolution of binarystars,aswellasprovidingvaluableastrophysicalinformation(likeprecisestellarmasses, radii,ages,luminositiesanddistances)totestandconstraincurrentastrophysicaltheory.These majoradvancespermittestsofcurrenttheoriesandideasinstellarastrophysicsandprovidethe foundations for the next steps in modeling and improvements in theory to be taken. 1. Introduction IAU Symposium 240, Binary Stars as Critical Tools & Tests in Contemporary As- trophysics, took place 22-25 August 2006, during the second week of the XXVIth IAU General Assembly in Prague, Czech Republic. The meeting lasted for 3-1/2 days and consisted of a mix of invited, contributed oral contributions and over 180 posters. This symposiumwastheresultofamergeroftwobinarystarsymposiaproposalsdevelopedfor the General Assembly. One proposal, originated from Commission 26 (Binary and Mul- tiple Stars) and led by Hartkopf, focused mainly on wider systems. The other proposal was organized by Commission 42 (Close Binaries) and led by Harmanec and Guinan, and it focused primarily on close/interacting binaries. 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TITLE AND SUBTITLE 5a. CONTRACT NUMBER Introduction & Overview to Symposium 240: Binary Stars as Critical 5b. GRANT NUMBER Tools and Tests in Contemporary Astrophysics 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION U.S. Naval Observatory,Astrometry Department,Washington,DC,20392 REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF ABSTRACT OF PAGES RESPONSIBLE PERSON a. REPORT b. ABSTRACT c. THIS PAGE Same as 12 unclassified unclassified unclassified Report (SAR) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 6 E. F. Guinan et al. recommended that thetwo proposals bemerged, and after hundreds of e-mail exchanges between the wide and close binary groups and their respective organizing committees and related commissions, the present symposium was organized with a broader program that includes all varieties and flavors of binary stars — both close and wide as well as near and far binaries and multiple stars systems. Most of the different types of binary systems discussed at the symposium are given in Figures 1 – 3. The various classes of binary systems composed of non-degenerate stars are shown in Figure 1, while Figure 2 shows binaries containing at least one degenerate component (white dwarf, neutron star orblackhole).Figure3showsrecentlydiscoveredbinarysystemswithplanetaryorbrown dwarf components. Note that our solar system would be included in Figure 3. Thesymposiumbroughttogether∼500astronomersfrom54countrieswhoareinvolved inallaspectsofbinaryandmultiplestarresearch,fromverylong-period,common-proper- motion pairs and other “fragile” binaries to short-period contact binaries, short-period binaries with degenerate components, as well as star/brown-dwarf/planet systems, with the aim of exploring interests common to all binary star researchers. Both the observa- tionalandtheoreticalaspectsofbinaryandmultiplestarresearcharerepresented,butthe mainthemesoftheprogramarethenewinformationandphysicalinsightsgleamedfrom therecentadvancesininstrumentationandtechniques.Themeetingalsoattractedthose interested in the observational and theoretical aspects of modern stellar astrophysics that depend very strongly on the fundamental properties of stars found primarily from binary and multiple stars. Sponsored by Division IV [Stars] and Commissions 26 and 42, the symposium has also received strong support from Division V [Binary & Variable Stars], as well as from seven other commissions and three working groups. We thank these Divisions, Commissions, and Working Groups for their support. The resulting program benefited greatly from the infusion of new ideas and differing perspectives from the two binary star communities, which resulted in a broader and more comprehensive program and most of all a more vibrant and interesting meeting. The format for the symposium was a mix of invited oral review presentations (∼30 min) and more narrowly-focused topical (∼15–20 min) presentations. There were also over twenty short oral/poster presentations (5–10 min) that were selected by the SOC from >180 submitted posters. These are also included in this volume, as are abstracts of all the poster presentations posted to the publisher’s website. 1.1. Venue and dedication of the symposium It is fitting that this symposium was held in the Czech Republic, because much of the pioneeringworkonbinaryandvariablestarshasbeencarriedoutinCentralandEastern Europeforoveracentury.ThemeetingwasalsofittinglyheldinthecityofPrague,home to both Tycho Brahe and Johannes Kepler. It is noteworthy that Tycho carried out the first accurate astrometric measurements, while Kepler’s laws of orbital motion play such an important role in binary star studies. As the first joint meeting of the “close and wide” binary communities in recent memory, it was also appropriate to jointly dedicate thesymposiumtooutstandingrepresentativesofbothofthose“close”and“wide”worlds of binary and multiple star research: Mirek Plavec of the Czech Republic and the late CharlesWorleyoftheUnitedStates.BothgentlemenattendedthelastGeneralAssembly heldinPraguein1967,andPlavecalsoattendedtheopeningsessionofthe2006meeting. Poster papers about both astronomers, displayed at the meeting and included here in these proceedings, provide brief descriptions of their professional careers as well as their many important contributions to binary and multiple star research. Also,thereadershouldtakenoteoftheposterpaperbyAugensen,Mason&Hartkopf (see publisher’s website) discussing the life and work of Dr. Wulff Heintz, who passed Introduction & Overview to Symposium 240 7 Figure 1. The period range and astrophysical interests of binary systems with non-degenerate components. away in June 2006, shortly before this symposium was held. Noteworthy among Wulff’s manycontributionstobinaryandmultiplestarresearchisthathemadeatotalof54,000 micrometer measures of double stars and discovered over 900 new pairs. Wulff is second only to Willem van den Bos in the total number of astrometric measures. Interesting enough, Charles Worley is in third place in this category, with over 40,000 individual astrometric measures and the discovery of 39 new faint, cool stellar companions. 2. Background: Major Advances in Instrumentations and Techniques In 1992, IAU Colloquium 135, “Complementary Approaches to Double and Multiple Star Research,” was held at Callaway Gardens (near Atlanta, Georgia), and was meant to emphasize the expanding overlap of observational opportunities offered to binary star researchers by advances in precise radial velocity techniques, interferometry, etc. Addi- tional topics included recent advances (for those times) in our knowledge of duplicity for young stars and pre-main sequence stars, the latest theories of binary and multiple star formation, and the tantalizing first results from HST and Hipparcos. The meeting suc- cessfully brought together nearly one hundred astronomers with a diversity of expertise until then rarely found at a single meeting on binary stars. Muchhas changed in theensuing14 years! HSTis now approaching theendof its life, and its larger successor, the James Webb Space Telescope (JWST) is under construc- tion. Hipparcos results have been published and well-studied, and the next generation of astrometry satellites (such as the Space interferometry Mission [SIM] and Gaia) now 8 E. F. Guinan et al. Binary Systems with Degenerate Components CVs (wd + dM) Symbiotic Binaries Mira AB (M III + wd) determining AM CVnBinaries white dwarf Post CE Binaries SNIaProgenitors? properties V471 Tau(K2 V + wd) wind accretion mass DE CVn(dM3 + wd) loss to ISM accretion processes Sirius Systems (wd + ms) accretion properties of neutron CH, S, BaStar Binaries stars and black holes (M III + wd) nucleosynthesis SN progenitors X-ray Binaries Barium Stars accretion processes (micro quasars) end-stages of stellar evolution LMXBs properties of HMXBs condensed matter n* + wd Be* / n* Binaries n* + ms X Per n* + n* Binary Pulsars X-ray Black Hole (bh) Binaries wd + wd superheated plasma 2.4 hrs 2.7 yrs 27 yrs 0.01 0.10 1.00 10 100 1000 10,000 ORBITAL PERIOD (in days) Figure 2. The period range and astrophysical interests of binary systems with degenerate components. under development promise results orders of magnitude greater in both precision and quantity. Speckle interferometry and adaptive optics have replaced visual micrometry as the routine methods of measuring visual binaries, while long-baseline interferometry has now produced a significant body of results for closer binaries, with the promise of an outburst of activity in the resolution of spectroscopic binary systems during the next fewyears.Fromastrometricandspectroscopicorbits,massesandotherimportantstellar propertiesaredeterminable.InterferometricresultsfromtheHSTFineGuidanceSensors (FGS) have also become more plentiful. As discussed in several papers at the meeting andinthis volume, therehave beendramatic changes intheway weconduct astrometry of binaries and profound increases in the reliability of the results. Similar tremendous advances continue in other areas as well. Variability-induced mo- tionandothercolor-baseddetectionmethodsarebeingusedtominetheSDSSdatabase for new binaries and may be used with Gaia (http://www.rssd.esa.int/index.php? project =GAIA&page=index) and SIM (http://planetquest.jpl.nasa.gov/SIM/ sim index.cfm) data as well. Superior infrared detectors and techniques, as well as the recent availability of infrared spectroscopy and imaging from space with the Spitzer Space Telescope (SST), are revolutionizing the study of pre-main sequence binaries and binaries with cool star and brown dwarf components. Ever more accurate radial velocity techniques have yielded long-period orbits that further blur the distinction between the traditional spectroscopic and visual separation/period regimes and yield accurate stellar masses across the spectral range – not to mention the new short-period systems and 200+exoplanetsdiscoveredoverthelastdecade!Withinthenextseveralyearshundreds Introduction & Overview to Symposium 240 9 Binary Systems with Planetary/Brown Dwarf Components properties of brown dwarfs & Binary Systems with BD components formation / BD + ms, BD + wd, BD + BD, BD + planet evolution of bd(cid:146)s accretion processes Single-line Spectroscopic Binary Star-Planet Systems properties of giant planet orbits (120+ known) Mp sin i (cid:147)Hot Jupiter(cid:148)Systems e.g. 51 Peg Systems radius and mass Eclipsing Binary Star / Planet Systems (ms + planet) of planets e.g. HD 209458, HD 189733 (10+ known) KEPLER / COROT Missions to detect >400 EBswith planets 2.4 hrs 2.7 yrs 27 yrs 0.01 0.10 1.00 10 100 1000 10,000 ORBITAL PERIOD (in days) Figure 3. The period range and astrophysical interests of binary systems with brown dwarf and planetary components. of additional exoplanets (some with diameters as small as the Earth) are expected to be discovered by the CoRot and Kepler missions. 2.1. Organization of the papers The papers in this volume are organized into three major themes, as discussed in Sec- tions 3–5 below. “New Observing Techniques and Reduction Methods” includes (3.1) Observing with high angular and spectral resolution; (3.2) New possibilities for stan- dard observational techniques; (3.3) Improved methods of data analysis; and Observing in the era of large scale surveys. “Binary Stars as Critical Tools (for obtaining direct andreliable Astrophysical Information)” consists of(4.1) Theneedtoimprove basiccal- ibrations and increasing possibilities of classical methods and (4.2) Evolutionary models for binary and multiple stars. Finally, “Binary Stars as Critical Tests” focuses on (5.1) Binary stars as probes of our Galaxy and (5.2) Asteroseismology and Stellar Activity. The volume concludes with excellent summaries on the observational aspects (given by ColinScarfe)andonthetheoreticalaspects(givenbyVirginiaTrimble)andafewclosing commentsfromHartkopf.Thepapers(bothoralpresentationsandposters)presentedat this symposium and included in this volume and on the publisher’s website demonstrate that these are indeed very exciting times for the studies of binary and multiple star systems. 10 E. F. Guinan et al. 3. New Observing Techniques and Reduction Methods 3.1. Observing with high angular and spectral resolution Recent results from powerful long-baseline interferometers both in the northern and southernhemispheresarediscussedbyHalMcAlisterandJohnDavis.Theseinstruments are yielding unprecedented high angular resolution measures, and refined astrometric orbits, of an increasing number of binaries with smaller and smaller separations. These papers show that astrometric measures are now closing the gap between wide binaries and shorter-period spectroscopic binaries and are providing fundamental properties of the component stars not possible previously except for eclipsing systems. In many cases additionalcomponentshavebeendiscoveredtosinglestarsanddoubles.Asdiscussedby YuriBalega,interferometryusingsingletelescopes(mostlyfromspeckleinterferometry), is discovering many new binaries and multiple star systems, and these observations are routinely yielding high precision orbits. Also with interferometric and adaptive optics techniques,manysingleandbinarystarsarebeingfoundtoharborfainterstellarand,in somecases,brown-dwarfandplanetary-sizecompanions.AsdiscussedbyMikeShaoand Xiaopei Pan, the Space Interferometry Mission (SIM), currently planned for 2015, will be capable of ultra-high angular precision, microarcsecond (µ-sec) astrometry that has the capability of astrometrically detecting components with masses as small as Earth. Inacontributedoral/posterpresentation,FrankFekel&JocelynTomkindiscussseveral spectroscopicbinarycandidatesthataremostsuitableforground-basemultipleaperture interferometry. A decade ago, most astronomers (including most members of Commission 42) would havebeenveryhappywithstellarradialvelocitymeasureswithprecisionsof≈1–3km/s. However,overthelastdecaderadialvelocitymeasuresusing,forexample,iodinegascells, are routinely being obtained with precisions of better than 5 m/s. More recently, radial velocity measures are being accomplished with precisions reaching as low as ∼1 m/s. As discussed at the meeting by Artie Hatzes (but not included in the book) and oth- ers, over 200 extrasolar planets have so far been discovered, mostly from these high- precision radial-velocity programs (see, e.g., http://exoplanets.org). It appears that ∼5% of nearby solar-type (i.e., dG and dK) stars are accompanied by Jupiter-size plan- ets, many of these (known as “Hot Jupiters”) are orbiting very close to their host stars. We have not yet reached the needed observational precision to detect Earth-size plan- ets from high-precision spectroscopy but, as reported by several papers here, Earth- size planets should soon be discovered with SIM astrometry. These discoveries may come more immediately from high-precision photometry missions such as CoRot and Kepler, however, as discussed later in the book. Excellent summaries of high-precision radialvelocityworkaregivenbyMarcy&Butler(http://exoplanets.org/)andMayor (http://obswww.unige.ch/∼udry/planet/). For the most part, the high-precision ra- dial velocity work is focused on finding planets. However, in the near future, these mea- sures will also be secured for double-line eclipsing binaries to obtain very accurate fun- damental properties. 3.2. New possibilities for standard observational techniques It is commonly thought by many stellar astronomers that observing time on large tele- scopes is impossible to get because this precious time is monopolized by extragalactic astronomers. As discussed in papers by Ignasi Ribas and Alceste Bonanos, however, this isclearlynotthecase.Itisstillpossibletogetobservingproposalsonbinarystarspassed by the scrutinizing eyes of TACs guarding the time on large telescopes. Ribas focuses mainly on spectroscopic observations of faint, but astrophysically important, eclipsing Introduction & Overview to Symposium 240 11 binaries that are members of Local Group galaxies (mostly O/B binaries) and intrin- sically faint low-mass red-dwarf and brown-dwarf eclipsing systems. Bonanos discusses observations of O/B eclipsing binaries in the Local Group and how these stars are pro- viding independent, accurate distances to the Large and Small Magellanic Clouds, M31 andherrecentworkondetermininganaccuratedistancetotheTriangulumspiral(M33). There are a number of posters on these topics presented at the meeting. Brian Mason discusses the results of (in some cases) over a hundred years of standard (or classical) astrometric observations of visual and multiple stars and presents some interesting results and statistics. As demonstrated by previous papers, many additional fainter members of binary and multiple star systems are being discovered in increasing numbers,thankstotheadvancesininstrumentationandtechnologies(mostlyfrominter- ferometry,adaptiveopticsandhighprecisionspectroscopy).Hartkopfreportsoneffortsto meetthisproblemofsuccessinhispaperaboutthenomenclatureofmultiplestarsinthe Washington Multiplicity Catalog (WMC; http://ad.usno.navy.mil/wds/wmc.html). Alsoincludedhereareseveralinterestingoral/postercontributions.Thesepapersfocus onawiderangeoftopicsthatincludeanewstudyandmassdeterminationofthePolaris multiple star system (Nancy Evans et al.), a new and very interesting eclipsing binary (DE CVn) consisting of a dM3 star and a cool white dwarf that must have evolved through the common-envelope stage of binary star evolution (Else van den Besselaar et al.), a new study of the eclipsing triple system U Oph (Luiz Paulo Vaz et al.) and a new study of the very young binary stars in the Orion Nebula Cluster (Rainer Ko¨ehler et al.).Additionally,thereisarelatedposterpaperonDECVnbyU¨mitGoker&Gu¨nay Tas.Alsohere,PetrHadravadiscussesnewtrendsindisentanglingthespectraofmultiple stars using methods that he pioneered. 3.3. Improved methods of data analysis Powerful and improved methods for the analysis of binary and multiple stars, such as spectra disentangling, Doppler tomography, Doppler imaging and eclipse mapping, as well as other innovative modeling procedures are the primary themes of this section. Herman Hensberge & Kreˇsimir Pavlovski present detailed discussions of the modern analysistechniquesnowbeingappliedmainlytospectroscopicbinaries.Theydiscussthe advantages and disadvantages of the different methods to extract precise radial velocity informationfromspectroscopicbinaries.Mostoftheemphasisisonspectradisentangling andtheinformationgained.MercedesRichardsdiscussesDopplerTomographyasapplied tomappingstreamsanddisksinAlgolsystems,whileKlausStrassmeierdiscussesDoppler Imaging and constructing eclipse maps of spots and other stellar surface features on chromospherically active components of close binary systems — such as RS CVn stars. In a thoughtful paper by the developer of the most widely used program for analyzing and modeling eclipsing binary light curve data, Bob Wilson focuses mainly on advances and innovations in light curve modeling developed over the last three years. He also looks to the future and discusses methods for the modeling of the tens of thousands of light curves of eclipsing binaries expected over the next several years. Wilson advocates publication of future lightcurves of eclipsing binaries not in delta-mags, but rather in physicalunitssuchasergs/sec/cm2.Thisiseasiersaidthandone,butwouldallowdirect distance estimations within the light and radial velocity curve modeling. In the same section, Theo ten Brummelaar discusses the practicalities of reducing multi-aperture interferometric data. Applications of improved methods of binary star analysisarepresentedbyGeraldinePetersinherstudyofthebipolarjets,hotinteracting regions and colliding winds in OB interacting binaries, and by Styliani Kafka on the 12 E. F. Guinan et al. evidence for chromospheric activity on the cool, low mass secondaries of cataclysmic variable binaries. In an oral-only presentation, Dimitri Pourbaix discussed the use of large-scale surveys for discovering and studying new binary stars. A good example of this is found in the multi-band astrometry detection of binaries from the Sloan Digital Sky Survey (SDSS). These binaries are detected from the astrometric color-induced displacement technique (CID) in which the displacement of the photocenter between different bandpasses arises from a varying contribution of differently colored components to the total light. (see Pourbaix et al. 2004, A&A, 423, 755 for more details.) SeveralinterestingcontributedpapersappearingarethecontributionsofDiegoFalceta- Gon´calves et al. on the massive binary/multiple star system η Carinae and the paper by Bob Stencel about another favorite binary — the 27-yr eclipsing (F2I + disk) binary, (cid:2)Aurigae.Itisnoteworthythat(cid:2)Aurisscheduledtostartitsnext∼2year-longeclipsein 2009.Anotherfamous(infamous?)binarytojoinηCarand(cid:2)Aurinthissectionisβ Lyr. PavelChadimaandcompanyanalyzedhundredsofspectraforthisperplexingbinaryand, using the KOREL program, found strong evidence that supports mass accretion and the presence of a thick accretion disk with bi-polar jets, as well as a circumbinary envelope. It will be interesting in the future to image β Lyr with the next generation of multi- aperture interferometers. This session has a great number of interesting posters worth visiting. As discussed in the papers by Wilson, Ribas and others in this section, it will not be long before high-precision radial velocity data will be combined with high precision (∼1 mmag) photometric light curves of selected double-line eclipsing binaries, yielding the masses and radii of their component stars with uncertainties better than ∼0.2%. Now moststellarmassesandradiiareknowntypicallytonobetterthan∼5%.Examplesofthe high precision light curves of eclipsing binaries that are now even possible using the star trackeroftheWIREsatellitearegivenbyHansBrunttet al.TheCanadianMOSTmicro- satellite (http://www.astro.ubc.ca/MOST/) also currently has the capability of milli- magphotometry,butonlyafeweclipsingbinarieshavebeenobservedsofar.Asdiscussed in the next section, light curves, with even higher precisions (better than 0.1 mmag) are expected very soon with the CoRot and Kepler space missions. 3.4. Observing in the era of large-scale surveys Anotherimportantdevelopmentdiscussedinanumberofpapersandpostersatthismeet- ingisthebonanzaofnew(mainlyeclipsing)binariesdiscoveredoverthelastdecadefrom photometricsurveyandmonitoringprograms.Mostofthesebinarieshavebeenserendip- itously discovered from micro-lensing photometry programs such as EROS, OGLE, and MACHO. So far several thousand new eclipsing binaries have been found, mostly in the rich star fields of the Galactic Bulge and the Magellanic Clouds. Also, nearly a thou- sand additional eclipsing binaries have been discovered by the DIRECT program (see Bonanos’ paper) and by Ribas and collaborators in the M31 and M33 spiral galaxies. Some of these newly discovered extragalactic eclipsing binaries have been used to secure accurate distances to the Local Group galaxies (see also several posters in this section). A brief inventory of the eclipsing binaries found so far in Local Group galaxies is given in Figure 4. Butinthenearfuture,thankstoplannedground-basedpanoramicphotometricsurveys suchasPan-STARRS(http://www.pan-starrs.ifa.hawaii.edu/)andtheLargeSyn- optic Survey Telescope (LSST; http://www.lsst.org./) and several other programs, the numbers of eclipsing binaries are expected to swell to over 105 systems. How do we cope with such an abundance of riches? Several groups are trying to find the solution to Introduction & Overview to Symposium 240 13 EEcclliippssiinngg BBiinnaarriieess iinn tthhee LLooccaall GGrroouupp GGaallaaxxiieess Galaxy # of known EBs Notes The Milky Way ~4000 Traditional photometry & OGLE (Many in Bulge) LMC 5000+ EROS, OGLE, SMC 2000+ MACHO & MOA M31 400+ DIRECT Project (see Bonanos(cid:150)this volume) (also Ribas(cid:150)this volume) M33 40+ >105expected at m~24thmag (Bonanos(cid:150)this volume) Fornax ~15 Measured from 1/8 CCD chips of mosaic; (extrapolated value from mosaic: ~300) (Clementini(cid:150)priv. comm.) Leo I ~10+ Down to 24thmag. Only short period (P < 2 days) discovered so far. NGC 6822 6+ Only 25% of galaxy covered (Clementini & collaborators) Carina (dSp) 5+ Carina Project (Monelli& collaborators) Figure 4. Eclipsing binaries in local group galaxies. this by developing automated methods to analyzed thousands of light curves at a time. Andrej Prˇsa & Tomaˇz Zwitter discuss a very promising pipeline reduction method of analyzing large numbers of light curves, while Tsevi Mazeh and colleagues discuss their automatic approach and initial results when applied to the study of early-type binaries in the Magellanic Clouds. Their preliminary results indicate that, at least among B-type stars, binaries may be far less frequent in the LMC (<10%) as compared to similar stars in the solar neighborhood. There are posters and related papers at the conference by Jonathan Devor & David Charbonneau and by Aliz Derekas et al. In the same session there are fascinating papers by David Koch (and the Kepler team) about the ultra-high precision photometry expected from the Kepler mission and a related paper by Carla Maceroni and Ribas on the impact of very high precision photometry on close binary stars expected shortly from the CoRot space experiment (http://www.esa.int/science/corot/). These missions are expected to discover hun- dreds of additional planetary transit systems. Currently, about a dozen eclipsing planet- star systems have been uncovered. Also there are short papers presented by Panos Niar- chos et al. on the Gaia mission’s impact on binary star studies. Other interesting papers include the results of multiplicity studies of very young Herbig Ae/Be stars (Sandrine Thomaset al.)andtheresultsofamultiplicity studyinnearbysolar-typestars(Deepak Raghavan et al.), as well as a contributed paper on the feasibility of detecting planets in wide binaries from ground-based Adaptive Optics (AO) systems (Ralph Neuha¨user et al.).