COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 3399 Konkoly Observatory Budapest 4 December 1989 HU ISSN 0374 - 0676 PROGRAM OF PARALLAX MEASUREMENTS FROM SPACE FOR THE NEAREST ECLIPSING BINARIES The idea of making stellar parallax measurements from space was born ten years ago, after the preparation of "A Catalogue of Photometric Parallaxes of Eclipsing Binaries" (Dworak 1975). We selected a subset of 102 of the nearest eclipsing variables (all within 100 pc from the Sun) from the catalogue of Brancewicz and Dworak (1980). From our list, 95 stars have been selected by the HIPPARCOS Organizing Committee (Table I). We are in hope that we obtain positions and parallaxes for these stars as well as their brightness in the UBV system. More precise and homogeneous measurements and trigonometric parallax determinations of eclipsing binaries are needed for the following reasons: - to obtain the absolute geometrical and physical parameters of eclipsing systems which are necessary for theoretical studies of these systems; - to more accurately determine the empirical mass-luminosity relationship for the components of close binary stars, especially those of luminosity class IV (Dworak 1975; Griffiths et al., 1988); - to verify the method for determining photometric parallaxes of distant eclipsing binaries (Dworak 1975; Brancewicz and Dworak 1980) and of spectroscopic binaries (Dworak 1983); - to obtain the space distribution of binary stars, important information for investigating the structure of Galaxy in the neighbourhood of the Sun (Oblak 1983); - to verify the validity of the hypothesis of the nonexistence of single subgiants (Dworak 1985); - to determine the zero-point of the photometric parallax scale (absolute magnitudes) which is necessary for determining extragalactic distances and for verifying the value of Hubble's constant (de Vaucouleurs 1983); - to resolve some eclipsing systems which allow us to compare the parameters of visual double stars with the same parameters as close binary systems (Oblak and Chareton 1980). Table I BD HD ALPHA(1950) DELTA(1950) NAME V Sp. T deg h m s deg ' " m +08 19 1061 00 12 24.12 +08 32 36.3 UU Psc 5.9 F0IV+ +39 154 3765 00 38 04.31 +39 55 19.7 7.6 K2V +74 27 4161 00 42 18.42 +74 42 54.6 YZ Cas 5.6 A2V +23 106 4502 00 44 40.96 +23 59 43.9 Zet And 4.0 K1IIe -55 267 6882 01 06 17.24 -55 30 45.7 Zet Phe 3.8 B6V+ +06 189 7700 01 14 18.53 +06 32 53.0 UV Psc 9.5 G5 CD-50 410 9528 01 30 29.02 -49 47 01.4 AE Phe 7.9 G1/G2IV Sv*HV11634 01 49 12 00 -38 55 30.0 V572 Cen 11.0 ? +22 284 11763 01 53 03.35 +23 19 59.2 RR Ari 6.0 G8III CD-23 737 12180 01 56 40.39 -23 09 43.5 AA Cet 6.5 F2... +40 442 13078 02 05 59.31 +40 33 28.3 BX And 8.7 F2Vvar +45 3813 21033 02 06 39.52 +45 29 45.0 AR Lac 6.4 G2IV+... 02 33 47 00 -45 17 12.0 CO Eri 8.5 G0 +69 179 17138 02 44 22.77 +69 25 32.9 RZ Cas 6.3 A2V +40 673 19356 03 04 54.35 +40 45 52.4 bet Per 2.2 B8V +47 781 03 09 53.31 +47 55 23.2 LX Per 7.9 G4 +12 539 25204 03 57 54.37 +12 21 02.1 lam Tau 3.7 B3V+... -10 858 26609 04 09 46.52 -10 35 43.6 YY Eri 8.2 G5 AN 4.1913 04 31 52.00 +15 09 48.0 TY Tau 11.9 K0 -08 1050 05 08 50.59 -08 36 59.8 ER Ori 9.4 G1V: +19 886 34335 05 14 33.49 +20 04 47.8 CD Tau 6.8 F7V +33 1002 34364 05 15 01.25 +33 42 55.1 AR Aur 6.0 B9V+... Sv*HV2435269320 05 18 42.00 -68 16 36.0 RW Dor 10.0 K5 05 31 47.00 -81 37 18.0 TY Men 7.6 A3 CPD-76329 37513 05 32 00.30 -15 34 54.8 V1010 Oph 6.5 A5V +59 920 39220 05 50 28.95 +59 52 47.2 TU Cam 5.2 A2V +44 1328 40183 05 55 51.57 +44 56 40.6 bet Aur 1.9 A2IV+... +56 1125 44691 06 22 12.69 +56 18 51.5 RR Lyn 5.6 A3Vm +32 1324 46052 06 29 11.43 +32 29 32.8 WW Aur 5.7 A3m+... +82 174 44982 06 30 36.66 +82 18 46.3 SV Cam 9.3 G5V:+... CSV 847 263139 06 42 49.00 +34 29 00.0 GX Gem 10.6 G5 06 47 33.00 +47 44 00.0 HS Aur 10.4 G5 -16 1898 57167 07 17 12.31 -16 17 59.9 R CMa 6.2 F1V CD -69 461 07 37 50.00 -69 25 48.0 W Vol 9.9 K 08 28 13.00 +02 26 54.0 GK Hya 8.9 G4 CPD-78378 75797 08 44 58.11 -78 53 15.1 RS Cha 6.3 A7V CD-276141 77137 08 57 34.04 -27 37 10.5 TY Pyx 6.9 G5V +27 1706 08 58 58.00 +26 52 42.0 WY Cnc 9.3 G8V +55 1317 237786 09 06 18.43 +54 41 40.0 XY UMa 9.8 G5 -28 7373 82610 09 30 06.99 -28 24 24.3 S Ant 6.9 A9V -44 5573 82829 09 31 19.97 -44 59 10.8 S Vel 8.0 A5m... +56 1400 83950 09 40 15.40 +56 10 56.3 W UMa 8.3 F8V:p+.. +20 2437 10 05 34.60 +20 14 56.0 YY Leo 9.6 M2 CPD-63134307739 10 23 21 00 -63 23 00.0 EX Car 9.5 G0 +15 2230 92109 10 35 40.99 +14 31 39.5 UV Leo 8.0 G0V +10 2234 10 59 34.18 +10 09 53.2 AM Leo 8.6 F8Vn 11 02 29.00 +05 25 36.0 AP Leo 9.5 G0 +30 216 99946 11 27 25.57 +30 14 35.2 AW UMa 7.1 F0 +12 2437 106400 12 11 47.86 +12 05 55.3 AH Vir 8.8 K0V+... -18 3437 110139 12 37 37.34 -18 31 32.4 SX Crv 9.1 F8 +36 2344 114519 13 08 17.86 +36 12 01.1 RS CVn 8.2 F4V+... 13 29 44.00 +28 50 18.0 VZ CVn 9.3 G5 +26 2508 121648 13 53 51.75 +26 09 46.1 ZZ Boo 6.8 F2V -49 8609 124784 14 13 40.21 -49 42 49.0 V636 Cen 9.0 F8/G0V AN 29.193 14 15 01.00 +12 47 18.0 VW Boo 10.3 G5 -07 3938 132742 14 58 17.80 -08 19 18.1 del Lib 4.8 B9.5V +48 2259 133640 15 02 08.28 +47 50 53.3 i Boo 6.4 G0Vnvar +40 2857 15 06 18.00 +40 09 36.0 TZ Boo 9.7 G2V +62 1393 15 10 50.38 +62 02 48.6 BW Dra 9.2 B0 +62 1393 135421 15 10 50.66 +62 02 32.9 BV Dra 8.1 F7V +39 2849 15 11 39.00 +38 45 18.0 SS Boo 9.7 G5V:+... +27 2512 139006 15 32 34.14 +26 52 54.7 alf CrB 2.2 A0V +00 3562 150484 16 38 47.78 +00 36 08.5 V502 Oph 8.2 G2V+... +82 498 153751 16 51 00.90 +82 07 21.5 eps UMi 4.7 G5III +16 3130 155937 17 11 43.18 +16 24 27.6 AK Her 8.4 F8Vvar 17 33 51.00 -56 47 30.0 V535 Ara 7.5 A3 +05 3547 163611 17 54 24.33 +04 59 30.8 V566 Oph 7.5 F4V +15 3311 163930 17 55 51.37 +15 08 31.4 Z Her 7.1 F4IV-V +13 3495 17 56 20.78 +13 53 12.7 V508 Oph 9.2 A2 +09 3584 166231 18 06 58.35 +09 08 28.3 V839 Oph 9.0 F8V -15 4842 166126 18 06 58.30 -15 33 37.3 W Ser 9.3 F5Iab:pe +41 3021 18 14 14.00 +41 05 36.0 TZ Lyr 9.8 F5V +18 367 348635 18 23 26.70 +18 15 52.0 AW Her 9.9 G2IV -10 4814 18 46 25.72 -10 17 56.2 RS Sct 10.1 G0 -37 13001 175813 18 55 21.11 -37 10 28.0 eps CrA 4.8 F2V +10 3787 178125 19 04 37.31 +10 59 34.3 Y Aql 4.9 B8III +46 2641 179890 19 10 37.58 +46 14 18.2 FL Lyr 9.0 G0V +54 21931 85912 19 37 33.73 +54 51 21.6 V1143 Cyg 6.2 F6Va +47 3059 192909 20 13 55.49 +47 33 35.7 V1488 Cyg 4.3 K3IB+... Sv* SVS 309 20 17 31.00 +36 10 54.0 V346 Cyg 10.9 A5 +75 752 197433 20 38 03.01 +75 24 58.4 VW Cep 7.4 K0Vvar -46 13749 198827 20 51 17.42 -45 55 16.6 SU Ind 9.7 F5/F6V CPD-702812199005 20 53 51.33 -70 36 58.5 KZ Pav 7.6 F2+... -15 5848 199603 20 55 55.85 -14 40 38.0 DV Aqr 6.2 F0IV +27 3952 200391 21 00 16.43 +27 36 33.3 ER Vul 7.6 G0V+... 21 05 45.00 +51 50 48.0 V1061 Cyg 9.1 F8 -16 5943 207098 21 44 16.99 -16 21 18.4 del Cap 3.0 A7IIIm -16 6074 22 20 35.00 -15 35 06.0 BW Aqr 10.0 F7 22 31 59.00 -20 07 .0 EE Aqr 8.1 F0 +37 4717 216598 22 51 22.54 +37 40 18.9 SW Lac 10.1 K0Vvar +52 3383 218915 23 08 52.33 +52 47 12.1 RT And 7.2 O9.5Iab +01 4695 219113 23 10 50.56 +02 29 10.0 SZ Psc 7.0 K1IV-V+.. In order to obtain homogeneous results for the geometrical and physical parameters, new or additional observations of eclipsing binaries from the HIPPARCOS program are necessary, especially for the stars listed in Table I (for which only the spectral type of bright component is given). The solution of light curves from photoelectric observations is also needed for accurately determining the geometrical parameters of each eclipsing system. The determination of the spectral type and the luminosity class of the secondary components of some eclipsing binaries are especially needed. Acknowledgements: We would like to thank J. Colin and E. Davoust for inviting one of us (T.Z.D.) in the Bordeaux and Toulouse observatories, respectively, and for supporting his visit. T. ZBIGNIEW DWORAK EDOUARD OBLAK Institute for Environmental Observatoire Besancon, Besancon Forming and Protection UA 04389 du CNRS University of Mining and 41 bis Avenue de l'Observatoire Metallurgy, Cracow, Poland 25044 Besancon, France and Observatoire de Bordeaux I et Observatoire Midi-Pyrenees, Toulouse, France References: Brancewicz, H.K., Dworak, T.Z.: 1980, Acta Astron., 30, 501. [BIBCODE 1980AcA....30..501B ] de Vaucouleurs, G.: 1983, Astron. J., 268, 468. [BIBCODE 1983ApJ...268..468D ] Dworak, T.Z.: 1975, Acta Astron., 25, 383. [BIBCODE 1975AcA....25..383D ] Dworak, T.Z.: 1983, Acta Astron., 33, 431. [BIBCODE 1983AcA....33..431D ] Dworak, T.Z.: 1985, Acta Astron., 35, 109. [BIBCODE 1985AcA....35..109D ] Griffiths, S.C., Hicks, R.B., Milone, E.F.: 1988, J. Roy. Astron. Soc. Can., 82, No. 1, 1. [BIBCODE 1988JRASC..82....1G ] Oblak, E.: 1983, Astron. Astrophys., 123, 238. [BIBCODE 1983A&A...123..238O ] Oblak, E., Chareton, M.: 1980, Astron. Astrophys. Suppl., 41, 225. [BIBCODE 1980A&AS...41..255O ]