J/A+A/376/144 BV(RI)_C_H{alpha} photometry of NGC 663 (Pigulski+, 2001) ================================================================================ The young open cluster NGC 663 and its Be stars. Pigulski A., Kopacki G., Kolaczkowski Z. =2001A&A...376..144P (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Clusters, open ; Stars, Be ; Photometry, UBVRI ; Photometry, Cousins ; Photometry, H-alpha Keywords: stars: emission-line, Be - open clusters and associations: individual: NGC 663 Abstract: We present new BV(RI)_C_H{alpha} photometry of the young open cluster NGC 663. The H{alpha} photometry is complete down to magnitude R_C_=15.4, corresponding to spectral type A5 for the cluster members. This allows detection of mild and strong H{alpha} emission in all B-type stars in the cluster. In addition to the 22 Be stars known in the observed field of NGC 663, we discovered four new faint stars of this type. We find that Be stars in NGC 663 cover the whole range of the B spectral type. They are, however, most populous among stars with spectral types falling in the range between B0 and B3, where their fraction amounts to 31+/-8%. Among B-type stars later than B3, Be stars are much less abundant: only 7 out of 101 observed stars, that is, 7+/-3%, were detected. About 70% of the observed Be stars in NGC 663 show detectable variations of light. In the time interval covered by our observations, the ranges of the largest variations reach 0.4mag in the I_C_ band. By means of the isochrone fitting, we derived the cluster distance of 2.1kpc, age of 20-25Myr, and the mean colour excess E(R-I)_C_=0.54mag, with a ~0.1mag scatter due to differential reddening. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table2.dat 171 1253 BV(RI)c and H{alpha} photometry, coordinates and cross-identifications for observed stars table3.dat 31 38 Epoch H{alpha} photometry of the observed Be stars -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 F7.1 pix Xpos X coordinate of a star in Fig.2, see Note (1) 8- 15 F8.1 pix Ypos Y coordinate of a star in Fig.2 17- 18 I2 h RAh Right Ascension (epoch J2000.0) 20- 21 I2 min RAm Right Ascension (epoch J2000.0) 23- 27 F5.2 s RAs Right Ascension (epoch J2000.0) 29 A1 --- DE- Declination sign (epoch J2000.0) 30- 31 I2 deg DEd Declination (epoch J2000.0) 33- 34 I2 arcmin DEm Declination (epoch J2000.0) 36- 39 F4.1 arcsec DEs Declination (epoch J2000.0) 42 I1 --- o_Bmag ? Number of B-filer measurements 44- 45 I2 --- o_Vmag ? Number of V-filer measurements 47- 48 I2 --- o_Rcmag ? Number of Rc-filer measurements 50- 51 I2 --- o_Icmag ? Number of Ic-filer measurements 53- 58 F6.3 mag Bmag ? B magnitude 60- 65 F6.3 mag Vmag ? V magnitude 67- 72 F6.3 mag Rcmag ? Cousins R magnitude 74- 79 F6.3 mag Icmag ? Cousins I magnitude 81- 84 F4.3 mag e_Bmag ? Error of B magnitude 86- 89 F4.3 mag e_Vmag ? Error of V magnitude 91- 94 F4.3 mag e_Rcmag ? Error of Rc magnitude 96- 99 F4.3 mag e_Icmag ? Error of Ic magnitude 101 I1 --- o_alphan Number of Halpha narrow filter measurements (2) 103 I1 --- o_alphaw Number of Halpha wide filter measurements (2) 105-109 F5.3 mag alpha ? {alpha} index (2) 111-114 F4.3 mag e_alpha ? Error of {alpha} index 117-119 A3 --- Pum Star number from Pummerer (1915) 121-124 A4 --- Gus ? Star number from Gushee (1919AJ.....32..117G) 125 A1 --- u_Gus [:] Uncertainty flag on Gus number 126-129 A4 --- Wal ? Star number from Wallenquist (1929MeUpp..42.....W) 130 A1 --- u_Wal [:] Uncertainty flag on Wal number 131 A1 --- n_Wal [*] *: object in table3.dat 133-134 I2 --- Zug ? Star number from Zug (1933LicOB..16..119Z) 136-138 A3 --- BG Star number from Becker & Guenther (1947AN....275..145B) 140-142 I3 --- HH ? Star number from Hopmann & Haidrich (1959MiWie..10..129H) 144-145 I2 --- HE ? Star number from Hoag et al. (1961PUSNO..17..343H), photoelectric sequence 147-149 I3 --- HP ? Star number from Hoag et al. (1961PUSNO..17..343H), photographic sequence 150 A1 --- u_HP [:] Uncertainty flag on HP number 151-153 I3 --- MH ? Star number from McCuskey & Houk (1964AJ.....69..412M) 154 A1 --- u_MH [:] Uncertainty flag on MH number 155-157 I3 --- Lat ? Star number from Latypov (1973, Tsirk. Astron. Inst. Tashkent No. 39, 12) 159-163 I5 --- MV ? Star number from Moffat & Vogt (1974VeBoc...2....1M) 165-167 I3 --- BR ? Star number from van den Bergh & de Roux (1978AJ.....83.1075V) 169-171 A3 --- Tap Star number from Tapia et al. (1991MNRAS.253..649T, Cl* NGC 663 Hoag NNW) -------------------------------------------------------------------------------- Note (1): Stars are listed according to the increasing right ascension. Note (2): The H{alpha} photometry we made was used to find stars showing H{alpha} emission. This was done by means of an {alpha} index, defined as a difference between the magnitudes of a star through a narrow and a wide filter. Our filters and, consequently, the {alpha} index resembles those used by others, namely Abt & Golson (1966, Cat. ), Tebbe (1969, Cat. ), Feinstein (1974, Cat. ), Dachs & Schmidt-Kaler (1975, Cat. ), Claria & Escosteguy (1981PASP...93..636C), Strauss & Ducati (981A&AS...44..337S), and Goderya & Schmidt (1994ApJ...426..159G). We made, however, no attempt to transform our {alpha} o that defined by others; it was left in the instrumental system. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- SAN ? Star number according to Sanduleak (1979AJ.....84.1319S, 1990AJ....100.1239S, Cl* NGC 663 SAN NNN in Simbad) 5- 8 A4 --- Wal Star number according to Wallenquist (1929MeUpp..42.....W) 9- 19 F11.3 d Epoch HJD of the epoch of observation 21- 25 F5.3 mag alpha {alpha} index 27- 31 F5.3 mag e_alpha Error of {alpha} index -------------------------------------------------------------------------------- Acknowledgements: Andrzej Pigulski ================================================================================ (End) Patricia Bauer [CDS] 11-Oct-2001