SPECKLE INTERFEROMETRY AT THE OBSERVATORIO ASTRONÓMICO NACIONAL. IV

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1 Revista Mexicana de Astronomía y Astrofísica, 48, (2012) SPECKLE INTERFEROMETRY AT THE OBSERVATORIO ASTRONÓMICO NACIONAL. IV V. G. Orlov, V. V. Voitsekhovich, and C. A. Guerrero Instituto de Astronomía, Universidad Nacional Autónoma de México, Mexico Received 2012 February 10; accepted 2012 March 12 RESUMEN Presentamos resultados de mediciones hechas mediante interferometría de motas de algunas estrellas estrellas binarias, llevadas a cabo durante septiembre y octubre de 2009 con el telescopio de 2.1-m del Observatorio Astronómico Nacional en SPM (México). Presentamos 200 mediciones de 196 pares con magnitud límite V = 12.3 para la estrella primaria. Las separaciones angulares medidas varían desde a Noventa y siete pares tienen separaciones menores que 1. El error medio en las separaciones es 0.03 y 1.5 en el ángulo de posición. La ambigüedad habitual de 180 se corrigió para la mayoría de los ángulos de posición, comparando con mediciones realizadas por otros observadores. ABSTRACT We present speckle interferometric measurements of binary stars performed during September and October of 2009 with the 2.1 m telescope of the Observatorio Astronómico Nacional at SPM (Mexico). We report here the results of 200 measurements of 196 pairs with a primary limiting magnitude of V = The measured angular separations range from to Ninety seven pairs have separations less than 1. The mean error in separation is 0.03 and 1.5 in position angle. The usual 180 ambiguity was corrected for a majority of position angles by comparison with observations performed by other observers. Key Words: binaries: visual stars: fundamental parameters techniques: high angular resolution techniques: interferometric 1. INTRODUCTION This is the fourth paper in the series of publications presenting the results of speckle interferometric observations of binary stars performed with telescopes of the Observatorio Astronómico Nacional (OAN) of the Instituto de Astronomía-Universidad Nacional Autónoma de México. Regular speckle interferometric measurements of binary stars have been made with telescopes of the OAN since 2008 (Orlov et al. 2009). This paper presents the results of double star observations carried out with the 2.1- m Telescope of Sierra San Pedro Mártir National Astronomical Observatory (OAN-SPM) in September and October of OBSERVATIONS AND RESULTS The observations were performed at the 2.1-m telescope of the Observatorio Astronómico Nacional TABLE 1 DISTRIBUTION OF PAIRS BY THEIR SEPARATIONS > < which is located at the San Pedro Mártir (Mexico). For these observations we used the DRAGON equipment (Voitsekhovich et al. 2005). This equipment was used for various observations at OAN telescopes during 2009 (Orlov et al. 2010). During the observations we had good seeing conditions. We estimated it was between 0.6 to 0.9 arcsec. Aberrations introduced by the telescope have similar values. As a result, long exposure images have a resolution of about 1.5 arc seconds. All the measurements were 177

2 178 ORLOV, VOITSEKHOVICH, & GUERRERO TABLE 2 SPECKLE MEASUREMENTS ON THE 2.1 M TELESCOPE HO AB A AB,C HJ TDS A COU AB COU COU ES TDS HO AB A COU COU COU COU STF COU HO AB A BU BRT COU BRT COU DOO COU AB A COU J ES A A TDS BU COU COU COU ES A TDS COU COU AB STF Hartkopf & Mason COU A TDS STF TDS HU COU COU BC ES AB A COU AB BU Ba,Bb VBS COU A A COU COU COU A COU Aa,Ab KU AB KU COU COU ES AB STF

3 SPECKLE INTERFEROMETRY AT THE OBSERVATORIO ASTRONÓMICO NACIONAL. IV 179 TABLE 2 (CONTINUED) COU AB WOR COU AB COU COU OL TDS TDS AB A Olević & Cvetković TDS COU COU COU COU COU COU HU COU A COU SEI COU AB HU COU TDT TDT COU TDT COU STF COU A AB STT A TDS COU Docobo et al HDS TDS A TDT COU HDS TDT TDT TDT TDT AB STT HO AB A TDT AB BU COU BC B HO Scardia et al COU AB BU COU WSI COU COU J Aa,Ab HDS COU TDT TDT HO Couteau TDT COU AB BU HO HDS AB BU TDT COU

4 180 ORLOV, VOITSEKHOVICH, & GUERRERO TABLE 2 (CONTINUED) A COU AB HO COU STF TDT TDT HDS TDT POP J BC ES Aa,Ab HO AB HO ES MLB Aa,Ab COU TDT A BC BU Hummel et al HDS HU CD COU ES TDT COU ES Aa,Ab COU COU HO AB HDS COU Docobo & Ling COU AB POP TDT COU COU POP AB A MLB AB WNC COU A ES COU HU ES HU BU TDT COU MLB COU AG TDT made through the R filter with a 640/130 nm bandpass window. After calibration we determine the pixel scale = arcsec/pixel and detector orientation. During six nights of observations we made 200 measurements of 196 pairs. Half of the observed binaries have separations less than 1. Table 1 shows how these 196 pairs are distributed according to their separations. Table 2 contains 200 measurements concerning 196 binary or multiple stars. The presentation of measurements is the same as in our previous publication (Orlov, Voitsekhovich, & Guerrero 2011). The first column contains the epoch-2000 coordinates in the format used in the Washington Double Star (WDS) Catalog (Worley & Douglass 1997). The second column gives the name of the star or the discoverer designation. The third column gives the epoch of the observation in fractional Besselian years. The two following columns contain the measured position angles given in degrees and the angular distances in arcseconds. The last three columns give the difference between observation and the ephemerides cal-

5 SPECKLE INTERFEROMETRY AT THE OBSERVATORIO ASTRONÓMICO NACIONAL. IV 181 culated for the date of observation, as well as references to publications in which orbital elements can be found (Hartkopf & Mason 2003). 3. CONCLUSION We have presented the results of binary star observations focused on binaries from WDS catalogue. In particular, we have been interested in new binaries discovered by Hipparcos. We confirmed 38 new binaries detected by Hipparcos. The main aim of this study was the selection of binaries with a fast relative motion, allowing to obtain candidates for determination of new orbits. The speckle interferometry program at the OAN telescopes is supported by the Dirección General de Asuntos del Personal Académico (Universidad Nacional Autónoma de México) under projects IN and IN (PAPIIT). REFERENCES Couteau, P. 1958, J. Obs., 41, 91 Docobo, J. A., & Ling, J. F. 2003, A&A, 409, 989 Docobo, J. A., Tamazian, V. S., Andrade, M., Ling, J. F., Balega, Y. Y., Lahulla, J. F., & Maximov, A. A. 2008, AJ, 135, 1803 Hartkopf, W. I., & Mason, B. D. 2003, Sixth Catalog of Orbits of Visual Binary Stars (Washington: USNO), , AJ, 142, 56 Hummel, C. A., Mozurkewich, D., Armstrong, J. T., Hajian, A. R., Elias, N. M., II, & Hutter, D. J. 1998, AJ, 116, 2536 Olevic, D., & Cvetkovic, Z. 2005, RevMexAA, 41, 17 Orlov, V. G., Voitsekhovich, V. V., Guerrero, C. A., Ángeles, F., Farah Simon, A., Luna, E., & Vázquez Robledo, R. 2011, RevMexAA, 47, 211 Orlov, V. G., Voitsekhovich, V. V., Mendoza-Valencia, G. A., Svyryd, A., Rivera, J. L., Ortiz, F., & Guerrero, C. A. 2009, RevMexAA, 45, 155 Orlov, V. G., Voitsekhovich, V. V., Rivera, J. L., Guerrero, C. A., & Ortiz, F. 2010, RevMexAA, 46, 245 Scardia, M., Prieur, J. L., Koechlin, L., & Aristidi, E. 2002, Inf. Circ. 146 Voitsekhovich, V. V., Sánchez, L. J., Orlov, V. G., Garfias, F., & Benitez, R. 2005, RevMexAA, 41, 399 Worley, C. E., & Douglass, G. G. 1997, A&AS, 125, 523 V. G. Orlov, V. V. Voitsekhovich, and C. A. Guerrero: Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal , México, D.F., Mexico (orlov, voisteko, cguerrero@astro.unam.mx).