CDROM/AJ/V109/P0817 Photometry of WN8 Stars (Antokhin+ 1995) ================================================================================ The Enigmatic WN8 Stars: Intensive Photometry of Four Southern Stars on Time Scales From 30 min to 3 Months Igor Antokhin, Jean-Francois Bertrand, Robert Lamontagne, Anthony F. J. Moffat, & Jaymie Matthews <1995, AJ, 109, 817> =1995AJ....109..817A ================================================================================ Abstract: We present the first results of an extensive photometric study of the most instrinsically variable Wolf-Rayet stars: the WN8 subclass. Some 375 individual differential observations of WR16 and WR40 were obtained over a contiguous interval of ~3 months in a narrow visual continuum bandpass. Over the same interval, we obtained roughly 200 broadband V observations of the fainter WN8 stars WR66 and WR82. All four WN8 stars show significant random variability on time scales of hours to ~a day -- probably related to the stochastic formation, propagation, and decay of emitting/scattering inhomogeneities in the winds. Unlike for WR66 and WR82, the photometric behavior of WR16 and WR40 is more deterministic with ~two possible periods in the range ~2-30 days -- possibly related to some kind of LBV, binary, or rotation phenomenon. In addition, WR82 shows a possible secular decline during the 3 months and WR66 reveals a clear periodicity of 3.51 h. This short period may be related to nonradial pulsations or a spiral-in binary process invoking a low-mass, compact companion as seen in the massive x-ray binary Cyg X-3, a WN7 + c system of period 4.8 h. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table1.dat 79 8 Comparison stars for the WN8 stars table2.dat 30 367 Narrowband visual photometry for WR16 table3.dat 30 381 Narrowband visual photometry for WR40 table4.dat 30 219 Broadband visual photometry for WR66 table5.dat 30 163 Broadband visual photometry for WR82 table.tex 69 9 LaTeX document to format tables 2, 3, 4, & 5 table2.tex 67 382 AASTeX version of Table 2 table3.tex 67 396 AASTeX version of Table 3 table4.tex 66 234 AASTeX version of Table 4 table5.tex 66 178 AASTeX version of Table 5 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- WR WR number 5 1X --- --- Blank 6-14 A9 --- Other Other name 15-20 F6.2 mag v []? v magnitude 21-25 F5.2 mag b-v []? b-v color 26-27 2X --- --- Blank 28-29 A2 --- Cmp Comparison star number (C1 or C2) 30 1X --- --- Blank 31-39 A9 --- Name Comparison star name 40 1X --- --- Blank 41-42 A2 --- Sp Spectral type 43-47 F5.1 mag V V magnitude 48-55 F8.4 mag WR-C Difference between comparison and WR 56-63 F8.4 mag e_WR-C Error (sigma) in WR-C 64-71 F8.4 mag C2-C1 Difference between comparison star 72-79 F8.4 mag e_C2-C1 Error (sigma) in C2-C1 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat table3.dat table4.dat table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 F9.4 d HJD Heliocentric Julian Date - 2440000 10-16 F7.4 mag WR-C1 WR-C1 differential magnitude 17-23 F7.4 mag WR-C2 WR-C2 differential magnitude 24-30 F7.4 mag C2-C1 C2-C1 differential magnitude ------------------------------------------------------------------------------ ================================================================================ (End) Lee Brotzman [ADS] 26-Apr-1995