The UVES M Dwarf Planet Search Programme

The UVES M Dwarf Planet Search Programme Martin Kürster Mathias Zechmeister Michael Endl 2 Eva Meyer,@W/K@MBJ(MRSHSTSEXQ RSQNMNLHD 'DHCDKADQF&DQL@MX 2,B#NM@KC.ARDQU@SNQX4MHUDQRHSXNE 3DW@R@S TRSHM42 We present results from our search SURJUDPPHIRUH[WUDVRODUSODQHWV around M dwarfs carried out with UVES between 2 and 27 and enjoying ESO Large Programme status from April 24 to March 26. In our sample of 4 stars we have found one brown dwarf desert companion candidate, but no planetary mass companions. We have determined upper limits to the mass of possible companions, which, in the habitable zones of our better observed stars, reach the regime of a IHZ(DUWKPDVVHV6LJQL:FDQWSHULRGLF variability observed in Barnard s star is attributed to stellar activity. 3GDQD@QDMNVjQRSHMCHB@SHNMRSG@S, CV@QERS@QROQNUHCD@KDRRDEjBHDMSDMUH QNMLDMSENQSGDENQL@SHNMNETOHSDQSXOD OK@MDSRSG@M&l*L@HMRDPTDMBDRS@QR VGDQD@R-DOSTMDL@RROK@MDSR@MC OK@MDSRVHSG@EDV$@QSGL@RRDRf2TODQ Earths could be numerous around M CV@QER(SG@R@KRNADBNLDBKD@QSG@SSGD RSQHJHMFO@TBHSXNEAQNVMCV@QEBNLO@M ions orbiting G K stars at separations NE@EDV@RSQNMNLHB@KTMHSRJMNVM@RSGD brown dwarf desert extends into the,cv@qeqdfhld 'HFGOQDBHRHNMCHEEDQDMSH@KQ@CH@KUDKNBHSX LD@RTQDLDMSRNERSDKK@QQDkDW LNSHNMRHMCTBDCAX@MNQAHSHMFBNLO@M HNMG@UDRNE@QADDMSGDLNRSRTBBDRR ful method of discovering extrasolar plan ets and characterising their orbital OQNODQSHDR.QHFHM@KKXOK@MDSRD@QBG programmes mostly concentrated on Table.,@RRDRNESGDCHRBNUDQDCOK@MDSR @QNTMC,CV@QER@KTDRHMANKCE@BD@QDSQTD L@RRDRRDDSDWS KKNSGDQU@KTDR@QDLHMHLTL L@RRDR main sequence stars of spectral types F7 through K with masses in the range l,,cv@qerg@udnmkxaddm included in search programmes in the last EDVXD@QRADB@TRDNESGDHQE@HMSMDRR requiring large telescopes and/or a sub stantial amount of observing time to perform RV measurements with a preci sion of the order of a few ms LNMF SGDLNQDSG@MJMNVMDWSQ@RNK@Q OK@MDSRBTQQDMSKXJMNVMNMKXSGHQSDDM planets accompanying eight different M dwarfs have orbits determined by RV LD@RTQDLDMSR Table lists all planets around M dwarfs RNE@QCHRBNUDQDCVHSGSGDLDSGNC Masses are the minimum masses that correspond to the RV effect observable VGDMUHDVHMFHMSGDOK@MDNESGDNQAHS Since the RV method does not allow the determination of all parameters of the NQHDMS@SHNMNESGDNQAHSNMKXLHMHLTL L@RRDR@QDNAS@HMDC RB@MADRGNVM a viewpoint from within the plane of the NQAHSHRSGDLNRSOQNA@AKDB@RDRNSG@S these minimum masses are also the most OQNA@AKDL@RRDR%NQSVNNESGD,CV@QE OK@MDSRA@MCASGDSQTD L@RRDRBNTKCADNAS@HMDCAHR NARDQUDCSNSQ@MRHSHMEQNMSNEHSRGNRSRS@Q SGDQDAXRKHFGSKXCHLLHMFSGDRS@QKHFGS @MCBNMjQLHMFSG@SVD@QDQD@KKXUHDVHMF EQNLBKNRDSNSGDNQAHS@KOK@MD%NQ ASGD@RSQNLDSQHBCHROK@BDLDMS NMSGDRJXBNTKCADLD@RTQDCVGHBG allows for the complete determination of SGDNQHDMS@SHNMNESGDNQAHSNMSGDRJX In this article we report on our RV moni toring programme of 4 M dwarfs carried out with the UVES spectrograph at UT2 on Paranal between 2 and 27 and DMINXHMF$2.+@QFD/QNFQ@LLDRS@STR Star GJ 674 GJ 76 Components b 3 M Jup 2 M c d EQNL OQHKSN,@QBG*XQRSDQ DS@K3GHROQNFQ@LLDV@R designed to search for terrestrial planets HMSGDG@AHS@AKDYNMDNE,CV@QER 3GDjQRSAQNVMCV@QECDRDQSBNLO@MHNM NAIDBS@QNTMC@MfD@QKXSXODt,CV@QE (spectral types M M was found in this OQNFQ@LLDATSSGDRL@KKR@LOKDCHC MNSQDUD@K@MXOK@MDS@QXBNLO@MHNMR This is consistent with the small number NMKXOK@MDSRNQAHSHMFDHFGSCHEEDQDMS, dwarfs found to date by other RV sur veys that are observing several hundred RS@QR(MNTQR@LOKDVDB@MDWBKTCD SGDOQDRDMBDNETOHSDQL@RROK@MDSRENQ @VHCDQ@MFDNENQAHS@KODQHNCR6D CHCGNVDUDQjMCRHFMHjB@MSU@QH@AHKHSXHM Barnard s star that we attribute to stellar @BSHUHSXSGTRHMCHB@SHMFSG@SSGHRRS@Q L@XG@UDMNMRNK@QRTQE@BDBNMUDBSHNM O@SSDQMR Why M dwarfs? For an understanding of the formation and @ATMC@MBDNEDWSQ@RNK@QOK@MDSRHSHRNE utmost importance to determine the pres ence and orbital characteristics of planets around stars of as many different types @RONRRHAKD@MCDRODBH@KKX@QNTMCSGD LNRS@ATMC@MSSXODNERS@QSGD,CV@QER It is currently estimated that M dwarfs L@JDTO NESGDRS@QRHMSGD2NK@Q -DHFGANTQGNNC@MCOQNA@AKX@RHLHK@QjF ure holds for the fraction of M dwarfs in SGD&@K@WX@R@VGNKD,CV@QERG@UD RL@KKDQL@RRDRSG@M2NK@QSXODRS@QR #V@QERS@QRNERODBSQ@KSXODR,,@MC,G@UDQDRODBSHUDKX@MC RNK@QL@RRDR3GDRL@KKDQSGDRSDKK@QL@RR SGDFQD@SDQHRHSRQDkDWLNSHNMHMCTBDC AX@OK@MDS&HUDM@RDMRHSHUHSXSNjMC signals of a certain amplitude lower mass e Reference #DKENRRDDS@K,@QBXDS@K HUDQ@DS@K,@XNQDS@K!NMjKRDS@K 4CQXDS@K!TSKDQDS@K NGMRNMDS@K!NMjKRDS@K!TSKDQDS@K %NQUDHKKDDS@K!@HKDXDS@K The Messenger 36 June 29

Kürster M.DS@K3GD4$2,#V@QE/K@MDS2D@QBG/QNFQ@LLD OK@MDSRB@MADENTMC@QNTMC,CV@QER and terrestrial planets of just a few Earth L@RRDR@QDVHSGHMSGDQD@BGNERS@SDNE SGD@QSRODBSQNFQ@OGR Another interesting characteristic of M CV@QERHRSG@SSGDONSDMSH@KKXKHEDAD@QHMF QDFHNM@QNTMCHSB@KKDCSGDfG@AHS@AKD YNMDtHRLTBGBKNRDQSNSGDRS@QSG@MHS HRENQ2NK@QSXODRS@QR#DODMCHMFNMSGD RODBSQ@KRTASXODSGDG@AHS@AKDYNMDBNQ responds to orbital periods from a few C@XRSNRDUDQ@KVDDJR3GHRHR@BNMRD PTDMBDNESGDKNVKTLHMNRHSXNE,CV@QER In the visual a dwarf star of spectral type,,nq,hrqdrodbshudkx NQL@FMHSTCDRE@HMSDQSG@MSGD2TM SGDHQSNS@KKTLHMNRHSHDRQD@BGITRS NQQDRODBSHUDKXNESGD2NK@QU@KTD The UVES sample Target selection for our UVES search pro gramme was based on the following cri SDQH@2HMBDGHFGQDRNKTSHNMRODBSQNFQ@OGR strongly disperse the light and are there ENQDGTMFQXENQOGNSNMR@KKRS@QRG@CSN ADAQHFGSDQSG@ML@FSN@BGHDUD the necessary high RV measurement pre BHRHNM6HSGSGDDWBDOSHNMNENMDLHRBK@R RHjDC,FH@MSSG@SG@C@MDQQNMDNTRCHR tance entry in the catalogue of nearby RS@QR@KKRS@QR@QDBKNRDQSG@MO@QRDB The sample stars were also selected ENQRL@KK7Q@XKTLHMNRHSX@R@MHMCHB@SNQ NEKNVKDUDKRNE@BSHUHSX3NLDDSSGHR criterion a star must either not have been CDSDBSDCHMSGD.2 37Q@XR@SDKKHSD @KKRJXRTQUDXNQG@UD@M7Q@XKTLHMNRHSX below 27 ergs 'XMRBGDS@K 3VNDWBDOSHNMRSNSGHRQTKD@QDSGDJMNVM k@qdrs@q/qnwhl@"dmvghbgv@r HMBKTCDCRHMBDHSHRSGDRS@QMD@QDRSSNTR @MCSGDRS@QVGHBGV@RJMNVM to have a wide brown dwarf companion at @RDO@Q@SHNMNE@SKD@RS 4-@J@IHL@ DS@K6DHMHSH@KKXRDKDBSDCRS@QR but added another 2 when the survey ADB@LD@M$2.+@QFD/QNFQ@LLDHM OQHK Achievable RV precision and allocated time To achieve high RV measurement preci RHNMSGD4$2RODBSQNFQ@OGV@RTRDC 3GDG@AHS@AKDYNMD 3GDG@AHS@AKDYNMDHRCDjMDC@RSG@S region around a star where liquid water B@MDWHRSNM@QNBJXOK@MDSVHSG@RTHS@ ble CO 2 ' 2 O /N 2 atmosphere (Kasting DS@K'DQDSGDJDXSDQLHRfRTHS@ AKDtVGHBGLD@MRSG@SPTHSD@MTLADQ of atmospheric parameters need to have SGDQHFGSU@KTDR.UDQ@KKSGDSDQLG@AHS@ AKDYNMDHRMNS@UDQXVDKKCDjMDCBNM cept and it may well be that it will have to be expanded should life be found in LNQDDWNSHBDMUHQNMLDMSR,CV@QER@MCTOHSDQL@RROK@MDSR #TDSNSGDKNVL@RRDRNE,CV@QERNUH@M planets in orbits up to a few astronomical units (AUs would be relatively easy to jmcvhsgbtqqdmsoqdbhrhnmrtqudxr3n C@SDNMKXjUDRTBGBNLO@MHNMRSN, dwarfs have been found orbiting four dif EDQDMSRS@QRRDD3@AKD%HQRS@M@KXRDR indicate that the frequency of Jovian plan DSR@QNTMC,CV@QERHRQDK@SHUDKXKNV $MCKDS@KG@UDRGNVMSG@SHSHR ADKNVENQNQAHS@KRDO@Q@SHNMRTOSN NMD 43GHRU@KTDHRBNMRHCDQ@AKXGHFGDQ @QNTMC&l*L@HMRDPTDMBDRS@QRNE VGHBG@QDJMNVMSNG@QANTQNUH@M OK@MDSRVHSGHM 4 Radial Velocity RV (m/s Radial Velocity RV (m/s 2 2 2 2 2 2 2 22 23 24 2 26 27 Barnard s star (M4V Barycentric Julian Date BJD 24 rms = 3.3 m/s σ RV = 2.7 m/s 2 2 3 3 4 2 2 22 23 24 2 26 27 Proxima Cen (M.V 2 2 2 3 3 4 Barycentric Julian Date BJD 24 rms = 3.6 m/s σ RV = 2.3 m/s Figure. Time series of UVES differential RV measurements of Bar M@QCRRS@Q3GDRNKHC line represents the pre dicted RV secular accel DQ@SHNM3GDRB@SSDQNE the data around this line (rms and the RV meas urement error (σ RV are KHRSDCHMSGDOKNS Figure 2. Same as Fig TQDATSENQ/QNWHL@ "DM 4 The Messenger 36 June 29

together with its iodine gas absorption BDKK@RDKEB@KHAQ@SHMFCDUHBDSG@SBNQQDBSR ENQHMRS@AHKHSHDRNESGDHMRSQTLDMSNUDQSHLD The RV precision achievable in long expo RTQDRHDVHSGGHFGRHFM@KSNMNHRDQ@SHNR is 2 ms VGHBGBNQQDRONMCRSNCDSDQLHM ing the position of the stellar spectrum on the CCD detectors to within /7 of a OHWDKNQML RV (m/s Figure 3. Differential RV data for Barnard s RS@QOG@RDENKCDC VHSG@ODQHNCNEC The dashed line corre RONMCRSNSGDADRS jsshmfrhmtrnhc@ku@qh@ SHNM (MNQCDQSNL@JDSGDADRSTRDNESGDSHLD @U@HK@AKDSHLDENQNTQR@LOKDNERS@QRVD CDBHCDCSNR@BQHjBDRNLDNESGD@BGHDU@ AKDOQDBHRHNM@MCVNQJ@SSXOHB@K U@KTDRNElLR 3GDNARDQUHMFSHLD allocated to our survey was 6 h for SGDENTQRDLDRSDQ+@QFD/QNFQ@LLD OG@RDOKTRGENQMHMDRHMFKDRDLDRSDQ MNQL@KOQNFQ@LLDR RV time series The 4 stars in our sample were ob served VHSGCHEEDQDMSEQDPTDMBHDR3GDMTLADQ of visits per star ranged from just two vis HSRENQSVNNENTQRS@QRSG@SVDQDHLLD CH@SDKXHCDMSHjDC@RCNTAKDKHMDCRODBSQN scopic binaries and not followed up any ETQSGDQTOSN@MCUHRHSRQDRODB SHUDKXENQNTQADRSNARDQUDCS@QFDSR!@QM@QCRRS@Q@MC/QNWHL@"DMS@TQH.M average we have 2 measurements per star and no more than one visit for any FHUDMRS@QV@RL@CDHM@RHMFKDMHFGS 3GDSHLDRDQHDRENQNTQADRSNARDQUDC stars are shown in Figure (Barnard s star and Figure 2 (Proxima Cen; see also $MCK*XQRSDQ3GDC@S@@QD shown together with a solid line corre sponding to the predicted change in the RV of these nearby stars resulting from SGDHQLNUDLDMSNMSGDRJXB@KKDCSGD frdbtk@q@bbdkdq@shnmt3gdb@mad CDjMDC@RSGDBG@MFDHMCHRS@MBDNE@ RS@QEQNLTR6GDM@RS@QO@RRDRAXTR HSRHRjQRSMDF@SHUDQD@BGDRYDQN@SSGD point of closest approach and becomes ONRHSHUD@ESDQV@QCRRDBTK@Q@BBDKDQ@ SHNMHRSGTR@MDUDQHMBQD@RHMFDEEDBSRDD *XQRSDQDS@K RVs v@bshuhsxhm!@qm@qcrrs@q.2.4.6.8 Phase If this purely geometric effect is subtracted EQNLSGDC@S@SGDC@S@B@MSGDMAD subjected to period analysis in an attempt SNjMCODQHNCHBRHFM@KRSG@SVNTKCAD HMCHB@SHUDNE@MNQAHSHMFBNLO@MHNM(MSGD B@RDNE!@QM@QCRRS@QVDjMC@RHFMHjB@MS RHFM@KVHSG@ODQHNCNEC@MC@M @LOKHSTCDNEŸLR (Zechmeister DS@K*XQRSDQDS@K%HFTQD RGNVRSGDC@S@OG@RDENKCDCVHSGSGHR ODQHNC(ESGHRRHFM@KBNTKCAD@SSQHATSDCSN @MNQAHSHMFBNLO@MHNMSGHRNAIDBSVNTKC AD@2TODQ$@QSGVHSG@LHMHLTLL@RR NE (SVNTKCNQAHSRNLDVG@SNTSRHCD NESGDG@AHS@AKDYNMDNE!@QM@QCRRS@Q 'NVDUDQSGDQD@QDQD@RNMRSNADKHDUDSG@S SGDRHFM@KHROQNCTBDCAXSGDRS@QHSRDKE HDAXHSRRTQE@BD@BSHUHSX@MCHSRHMkTDMBD on the convective motions that carry the heat transport from the interior to the NTSDQQDFHNMRNE@KNVL@RRRS@Q6GDM DW@LHMHMFSGDKHMDRSQDMFSGNESGD'α line NMDjMCRSGDR@LDCODQHNCHBHSX 3GD'αKHMDNQHFHM@SDRHMSGDRSDKK@QOGNSN ROGDQD@R@M@ARNQOSHNMKHMDATSHSG@R superimposed emission components FDMDQ@SDCHMKNB@KHRDCRNB@KKDCfOK@FDt QDFHNMRHMSGDBGQNLNROGDQD@GHFGDQ @MCGNSSDQK@XDQNESGDRSDKK@Q@SLNROGDQD Examining in detail how the behaviour of SGD'α line strength is correlated with NTQLD@RTQDLDMSRVDjMCDUHCDMBD that the convection must be locally dis STQADCAXSGDL@FMDSHBjDKCRNE@BSHUD QDFHNMR6GHKDSGHRHR@VDKKJMNVMDEEDBS HM2NK@QSXODRS@QRVGDQDHSB@TRDR@MDS AKTDRGHESNESGDRSDKK@Q@ARNQOSHNMKHMDR it appears that in Barnard s star a net QDCRGHESHROQNCTBDCONHMSHMF@SETMC@ mental differences in the underlying behaviour of the surface convection of 2NK@QSXODRS@QR@MCSGHR,CV@QERDD *XQRSDQDS@KENQCDS@HKR Mass upper limits %@BDCVHSGSGDK@BJNE@RHFM@KEQNL@M orbiting planet one can determine which types of planets can be excluded @QNTMC@FHUDMRS@QADB@TRDSGDHQRHFM@KR VNTKCG@UDADDMENTMC3GHRJHMCNE analysis requires detailed simulations in which signals of hypothetical planets @QD@CCDCSNSGDNARDQUDCC@S@@MCSGD LNCHjDCC@S@@QDRTAIDBSDCSNSGD same tests that are employed to discover RHFM@KR Figures 4 and show the results of such simulations for Barnard s star and /QNWHL@"DMQDRODBSHUDKXEQNL9DBG LDHRSDQDS@K4OODQKHLHSRSNSGD mass of planets that would have been ENTMC@QDRGNVM3GDX@QDOKNSSDC@R a function of orbital distance of the planet EQNLSGDRS@Q@MCNENQAHS@KODQHNC(M ANSGjFTQDRUDQSHB@KC@RGDCKHMDRCDKHLHS SGDG@AHS@AKDYNMD(MANSGB@RDROK@MDSR VHSGLNQDSG@MjUD$@QSGL@RRDRB@M ADDWBKTCDCEQNLSGDG@AHS@AKDYNMD Note again that these values correspond to the most probable viewing direction EQNLVHSGHMSGDNQAHS@KOK@MDRNSG@S@ lower mass planet could still be hidden HMNTQC@S@HESGDUHDVHMF@MFKDVDQD The Messenger 36 June 29 4

Kürster M.DS@K3GD4$2,#V@QE/K@MDS2D@QBG/QNFQ@LLD Figure 4. Upper limits to the projected mass msini of hypothetical planets around Barnard s star as a function of separation (lower x@whr@mcnqahs@k period (upper x@whr/k@mdsr@anudsgdrnkhckhmd VNTKCG@UDADDMCDSDBSDCDQSHB@KC@RGDCKHMDR CDKHLHSSGDG@AHS@AKDYNMD'9 FQNRRKXCHEEDQDMS S 4VDDWBKTCD -DOSTMDL@RR OK@MDSRVGDQD@R TOHSDQL@RR planets should G@UDADDMENTMC@S 4 For the majority of our stars for which we could not secure as many measurements @RENQ!@QM@QCRRS@Q@MC/QNWHL@"DM the same type of simulations lets us exclude planets with masses in the range between the masses of Neptune (7 M and Saturn (9 M from the habitable YNMD@QNTMCSGDRS@Q Note that the necessary sensitivity to dis cover a given planetary signal depends very much on the phase of the signal with respect to the temporal measurement VHMCNV#@S@S@JDMMD@QSGDL@WHL@@MC minima of the signal carry much more HMENQL@SHNMSG@MC@S@S@JDM@SHMSDQLDCH @SDOG@RDR(MNQCDQSNDWBKTCD@OK@MDS VHSG@FHUDML@RRVDLTRSBNMRHCDQ @KKONRRHAKDOG@RDR@KRNSGNRDENQVGHBG VD@QDKD@RSRDMRHSHUD3GDQDENQDNTQ TOODQKHLHSR@QDQDK@SHUDKXBNMRDQU@SHUD KNVDQL@RROK@MDSBNTKCRSHKKADCHRBNU DQDCHEHSRRHFM@KG@R@E@UNTQ@AKD OG@RD(EHSBNQQDRONMCDCSN@OK@MDSSGD CRHFM@KHM!@QM@QCRRS@Q%HFTQD VNTKCAD@MDW@LOKD Detection Limit msini (M Detection Limit msini (M Orbital Period P (d HZ Barnard s star.... Orbital Distance a (AU Orbital Period P (d HZ Proxima Cen.... Orbital Distance a (AU Figure.2@LD@R%HFTQDATSENQ/QNWHL@"DM Detection Limit msini (M Jup Detection Limit msini (M Jup An oasis in the brown dwarf desert So far no brown dwarfs in orbits up to a few AU around their host star ( brown dwarf desert objects have been found around M dwarfs of spectral types,l,.tqrtqudxg@rmnventmcsgd jqrsrtbgnaidbs@bnlo@mhnmsnsgd,cv@qers@q*xqrsdqds@k %HFTQDRGNVRSGDSHLDRDQHDR @KNMFVHSGSGDADRSjSSHMF*DOKDQH@MNQAHS with a period of 69 d and an eccentricity NE3GDRS@QBNLO@MHNMRDO@Q@SHNM HR 4 From the RVs we determine a minimum L@RRNETOHSDQL@RRDR"NMRHCDQ HMF@KKONRRHAKDNQAHS@KNQHDMS@SHNMRVDjMC Differential Radial Velocity drv (km/s 24.. 2 32 2. 2. 26. 26. 27. 34 36 38 4 Barycentric Julian Date BJD 24 Figure 6. Time series of UVES differential RV measurements of GJ 46 along with the ADRSjSSHMF*DOKDQH@M orbit corresponding to a brown dwarf desert B@MCHC@SD 42 The Messenger 36 June 29

@BG@MBDOQNA@AHKHSXNESG@SSGD companion mass exceeds the mass SGQDRGNKCNETOHSDQL@RRDRADSVDDM AQNVMCV@QER@MCRS@QR6GDMBNLAHMHMF NTQC@S@VHSGSGD@RSQNLDSQHBLD@R TQDLDMSRL@CDAXSGD'HOO@QBNRR@SDKKHSD TRHMFSGDMDVQDCTBSHNMAXU@M+DDTVDM VDB@MOK@BD@MTOODQKHLHSSNSGD companion mass of 2 Jupiter masses and narrow down the chance probability SG@SSGDBNLO@MHNMHR@RS@QSNITRS,NRSKHJDKXHSHR@FDMTHMDAQNVMCV@QE RSQNLDSQHBENKKNVTO To determine the true mass of the com O@MHNMSN @MCSGDQDAXHSRM@STQD VDG@UDADFTM@M@RSQNLDSQHBENKKNVTO study with the NACO adaptive optics sys tem and infrared camera at UT4 (Meyer *XQRSDQ6D@HLSNLD@RTQDSGD NQAHS@KQDkDWLNSHNMNEQDK@SHUDSN @A@BJFQNTMCRS@QRDO@Q@SDCAXITRSt NMSGDRJX3GHRBG@MBDDMBNTMSDQL@JDR precise astrometric measurements possi AKDEQNLVGHBGSGDNQHDMS@SHNMNESGDNQAHS and hence the true mass of the compan HNMB@MADCDQHUDC From our RV measurements we can pre dict that the astrometric signal is at least LHKKH@QBRDBNMCROD@JSNOD@J corresponding to 4% of an image pixel in SGDDLOKNXDC- ".2B@LDQ@ATS CDODMCHMFNMSGDNQHDMS@SHNMNESGDNQAHS SGDSQTDRHFM@KL@XADBNMRHCDQ@AKXK@QFDQ BJMNVKDCFDLDMSR 6DSG@MJSGD$2..ARDQUHMF/QNFQ@LLDR"NLLHS tee and the Director s Discretionary Time Committee ENQFDMDQNTR@KKNB@SHNMNENARDQUHMFSHLD6D@QD also grateful to all of ESO staff who helped with the OQDO@Q@SHNMNESGDRDQUHBDLNCDNARDQU@SHNMR B@QQHDCSGDLNTSNQOQNBDRRDCUDQHjDC@MCCHR SQHATSDCSGDC@S@ MTLADQNEODNOKDG@UDBNMSQHA TSDCHML@MXV@XRSNL@JDSGHRRTQUDXG@OODM.TQSG@MJRFNSN2S!OG@MD!QHKK@MS6HKKH@L# "NBGQ@M2DA@RSH@M$KR QSHD/'@SYDR3GNL@R 'DMMHMF MCQD@R*@TEDQ2@AHMDDEEDQS%KNQH@M NCKDQ%Q!C!QHBNTDRMDK@MC2SDUD22@@Q References $MCK,DS@K O $MCK,*XQRSDQ, 'XMRBG,DS@K 2 *@RSHMF%DS@K(B@QTR *XQRSDQ,DS@K *XQRSDQ,$MCK,NCKDQ%3GD,DRRDMFDQ *XQRSDQ,$MCK,DEEDQS2,DXDQ$*XQRSDQ,HMProceedings of the th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun (/"NME/QNB -@J@IHL@3DS@K-@STQD U@M+DDTVDM% 9DBGLDHRSDQ,*XQRSDQ,$MCK, submitted 3GDRS@QENQLHMFQDFHNM-&" HMSGD2L@KK Magellanic Cloud is shown in this colour composite HL@FD3GDOHBSTQDBNLAHMDRHL@FDREQNLSGDHMEQ@ QDC- 2 2OHSYDQ2O@BD3DKDRBNODHMQDCSGD UHRHAKD$2.-33HMFQDDM@MCSGD7Q@X$2 7,, HMAKTDSNQDUD@KSGDLTKSHBNLONMDMSRSQTBSTQDNE CTRSRS@QR@MCGNSF@R2DD$2./ENQLNQD CDS@HKR The Messenger 36 June 29