J/A+AS/131/321 Long-term monitoring of active stars. VIII. (Cutispoto 1998) ================================================================================ Long-term monitoring of active stars. VIII. UBV(RI)c photometry collected in February 1992 Cutispoto G. =1998A&AS..131..321C ================================================================================ ADC_Keywords: Stars, variable ; Photometry, UBVRI ; Photometry, Cousins ; Stars, flare Keywords: stars: activity - stars: flare - stars: late-type - stars: variables - stars: population II - stars: pre-main sequence Abstract: As a part of an extensive program focusing on the global properties and evolution of active stars, high-precision UBV(RI)c photometry of 31 selected stars, collected at the European Southern Observatory over the 14-29 February 1992 interval, is presented. Significant evolution of the light curves, period variations and evidence for long-term variability of the global degree of spottedness are found. Some spectral classifications are revised and the inferred photometric parallaxes are compared, whenever possible, with the values measured by the Hipparcos satellite. Flare events were detected for the star HD 16157=CC Eri, EXO 055609-3804.4=TY Col and HD 119285=V851 Cen. Optical variability was discovered for the Pop II binary HD 89499. These observations contribute to the establishment of a time-extended photometric database which can give important clues on topics such as the stability of spotted areas, differential rotation, solar-like cycles and the correlation between inhomogeneities at different atmospheric levels. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 67 31 Comparison (c) and check (ck) stars for each program star table3.dat 37 58 V magnitude and colors for the c and ck stars derived from standard stars. table4.dat 103 31 Maximum luminosity and corresponding colors measured for the program stars ubvri.dat 63 418 UBV(RI)c data tables.ps 72 1366 PostScript version of tables 1-4 tables.tex 80 269 LaTeX version of tables 1-4 -------------------------------------------------------------------------------- See also: J/A+AS/119/281 : Long-term monitoring of active stars. V. (Cutispoto, 1996) J/A+AS/121/369 : Long-term monitoring of active stars. VI. (Cutispoto, 1997) J/A+AS/127/207 : Long-term monitoring of active stars. VII. (Cutispoto 1998) J/A+A/400/659 : Long-term monitoring of active stars. X. (Cutispoto+, 2003) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 A13 --- Star Program star 15- 24 A10 --- Name Other name of the program star 26- 35 A10 ---- Comp Comparison star name (c) 37- 45 A9 ---- Check Check star name (ck) 47- 49 I3 mmag e(v-c) Standard deviation for the v-c V-band differential magnitude for each series of N nights 51 I1 mmag e(ck-c) Standard deviation for the ck-c V-band differential magnitude for each series of N nights 53- 54 I2 --- N Number of nights 56- 58 F3.2 mag DeltaV Amplitude of the V-band light curve 60- 67 F8.5 d Per ? Period of variability -------------------------------------------------------------------------------- Table 2: Mean atmospheric extinction coefficients for La Silla site, obtained over the 14-29 February 1992 period --------------------------------------------------------------------- U B V R I --------------------------------------------------------------------- Mag/airmass .538 .308 .203 .165 .118 --------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 A10 --- Name Comparison or check star name 12- 15 F4.2 mag Vmag V magnitude 17- 20 F4.2 mag U-B U-B colour index 21 A1 --- u_U-B Uncertainty flag on U-B (1) 23- 26 F4.2 mag B-V B-V colour index 28- 31 F4.2 mag V-Rc V-Rc colour index 33- 36 F4.2 mag V-Ic V-Ic colour index -------------------------------------------------------------------------------- Note (1): Errors are of the order of 0.01 magnitudes. The symbol ":" denotes errors of the order of 0.02 magnitudes -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 13 A13 --- Star Program star 15- 24 A10 --- Name Other name 26- 30 F5.2 mag Vmag V magnitude 32- 35 F4.2 mag U-B U-B colour index 37- 40 F4.2 mag B-V B-V colour index 42- 45 F4.2 mag V-Rc V-Rc colour index 47- 50 F4.2 mag V-Ic V-Ic colour index 52- 72 A21 --- SpType Spectral Type 74- 75 A2 --- l_DistH [>= ] Limit flag on DistH 76- 80 F5.1 kpc DistH ? Distance range measured by the Hipparcos satellite 81 A1 --- n_DistH [-] Dash when interval 82- 86 F5.1 kpc DistH2 ? Upper limit when interval 88- 89 A2 --- l_Distph [>= ] Limit flag on Distph 90- 94 F5.1 kpc Distph Photometric distance inferred from the adopted spectral classification 95 A1 --- n_Distph [-] Dash when interval 96- 98 I3 kpc Distph2 ? Upper limit when interval 100-104 F5.2 mag Vmax V-band maximum luminosity ever observed -------------------------------------------------------------------------------- Byte-by-byte Description of file: ubvri.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 A10 --- Name Star name 11 A1 --- Note [fm] f: flare, m: Manfroid et al. 1995, Cat. 13- 24 F12.4 d HJD Heliocentric Julian date 26- 31 F6.5 --- Phase ? [0/1[ Phase (1) 32- 37 F6.3 mag Vmag V magnitude 39- 44 F6.3 mag U-B ? U-B colour index 46- 50 F5.3 mag B-V ? B-V colour index 52- 56 F5.3 mag V-R ? V-R colour index 58- 62 F5.3 mag V-I ? V-I colour index -------------------------------------------------------------------------------- Note (1): Phases are computed by using the following ephemerides: CC Eri (14-24 Feb 1992) HJD=2447129.52934 + 1.56145 X E UX For (14-28 Feb 1992) HJD=2448660.0 + 0.957 x E AG Dor (14-25 Feb 1992) HJD=2448666.0 + 2.533 x E YY Men (14-29 feb 1992) HJD=2448660.0 + 9.75 x E EZ Eri (14-28 Feb 1992) HJD=2448660.0 + 9.08 x E YZ Men (14-29 Feb 1992) HJD=2448666.5 + 19.31 x E UX Col (14-28 Feb 1992) HJD=2448660.0 + 2.29 x E AB Dor (15-28 Feb 1992) HJD=2444296.575 + 0.51479 x E V1321 Ori (14-28 Feb 1992) HJD=2448660.0 + 5.6 x E SZ Pic (14-29 feb 1992) HJD=2443931.54 + 4.905 x E TY Col (14-29 Feb 1992) HJD=2448660.0 + 3.62 x E V344 Pup (14-25 Feb 1992) HJD=2448331.5 + 11.761 IL Hya (14-28 Feb 1992) HJD=2441466.213 + 12.86833 x E LQ Hya (15-29 Feb 1992) HJD=2448660.0 + 1.61 x E LZ Vel (14-29 Feb 1992) HJD=2448660.0 + 44.57 x E HD 89499 (14-29 Feb 1992) HJD=2448660.0 + 5.574 SZ Crt (14-25 Feb 1992) HJD=2441389.0 + 11.58 x E V858 Cen (14-29 Feb 1992) HJD=2448666.324 + 1.04303 x E V829 Cen (14-29 Feb 1992) HJD=2448331.5 + 11.65 x E V838 Cen (14-29 Feb 1992) HJD=2448660.0 + 1.848 x E HU Vir (14-29 Feb 1992) HJD=2448331.5 + 10.424 x E IN Vir (14-29 Feb 1992) HJD=2448660.0 + 8.4 x E V851 Cen (14-26 Feb 1992) HJD=2448660.0 + 12.05 x E V841 Cen (14-29 Feb 1992) HJD=2448660.0 + 5.929 x E GX Lib (14-27 Feb 1992) HJD=2444678.4 + 11.134 V343 Nor (14-29 Feb 1992) HJD=2448660.0 + 4.32 x E V991 Sco (16-27 Feb 1992) HJD=2448660.0 + 3.27 x E V824 Ara (15-27 Feb 1992) HJD=2448660.0 + 1.71 x E For the constant stars or those stars for which the period is not known (HD 293857, SAO 121177 and HD 158394) there are only six columns in the data tables, the phases column being not reported. HD 293857 (14-27 Feb 1992) SAO 121177 (13-14 Feb 1992) HD 158394 (14-26 Feb 1992) -------------------------------------------------------------------------------- Acknowledgements: Giuseppe Cutispoto References: Rodono & Cutispoto, Paper I. 1992A&AS...95...55R Cutispoto, Paper II. 1992A&AS...95..397C Cutispoto, Paper III. 1993A&AS..102..655C Cutispoto, Paper IV. 1995A&AS..111..507C Cutispoto, Paper V. 1996A&AS..119..281C, Cat. Cutispoto, Paper VI. 1997A&AS..121..369C, Cat. Cutispoto, Paper VII. 1998A&AS..127..207C, Cat. Cutispoto et al., Paper IX 2001A&A...367..910C, Cat. Cutispoto et al., Paper X 2003A&A...400..659C, Cat. ================================================================================ (End) Patricia Bauer [CDS] 28-May-1998