Poretti dscut Gdor CW8

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Information about Poretti dscut Gdor CW8
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Published on November 15, 2007

Author: Jolene

Source: authorstream.com

Slide1:  PHOTOMETRIC AND SPECTROSCOPIC MONITORING OF DSCT, GDOR AND BCEP VARIABLES Recent and future observations Ennio Poretti INAF – Osservatorio Astronomico di Brera Slide2:  After CW6 (Orsay, May 2004) we have a better defined list of potential primary and secondary targets in both directions. They provide a map of the lower part of the instability strip. They are 6 Delta Scuti stars 1 EA + DSCT + SB2 star 1 hybrid GDOR + DSCT star 2 Gamma Doradus stars 2 Beta Cephei stars (Poretti et al. 2005, AJ 129, 2461) In summer 2004 it has been possible to start their characterization. New results have been obtained in the AntiCenter direction: Sierra Nevada (P. Amado and S. Martin) and S. Pedro Martir (M. Alvarez and E. Poretti) runs in January 2005. Slide3:  Positions of the DSCT+GDOR targets in the CMD HD 44195 GDOR+DSCT HD 181147 DSCT HD 50870 DSCT HD 170782 DSCT HD 170699 DSCT HD 44283 DSCT HD 172189 EA+SB2+DSCT HD 181555 DSCT (revised) HD 49434 GDOR HD 171834 GDOR Evolutionary tracks after Claret. (b-y)o indices and Magnitudes calculated by P. Amado. Slide4:  NOVEMBER 2003 (8 nights) JANUARY 2005 (4 nights) HD 44195, the hybrid GDOR + DSCT star v sin i = 58 km/s, in the field of HD 43587, f1=21.5 c/d Slide5:  First results on HD 50870, a DSCT star in the field of HD 52265 f1=17.15 c/d f2=14.00 c/d ………. Slow rotator, Veq sin i = 17 km/s Predominant mode Slide6:  The positioning of HD 58070 could be a critical item HD 52265 and HD 58070 are located on the edges. There are three Be stars close to HD 58070 Slide7:  HD 172189, orbital period has been detected: 5.702 d. Eccentric orbit with only one minimum. DSCT pulsation: frequencies in the 18-20 c/d interval. (Martin et al., A&A, accepted) The RV curve is the goal of the spectroscopic observations planned in next June (OHP, SLN, ESO). Target of a STEPHI campaign in 2004. Slide8:  HD 180642, Beta Cep multiperiodic variable Monitored at SPM and with Mercator telescope (Aerts et al., in preparation). Agreement between theoretical and observed frequencies (low degree modes). Dominant term identified as the Fundamental radial mode Light curve solution will be refined in June. Slide9:  HD 44195 hybrid HD 43587 Y f=21.5 c/d f< 5c/d 7.56 F0 58 km/s HD 50870 DSCT HD 52265 Y f=17.5 13-15 8.88 F0 17 km/s HD 44283 DSCT HD 43587 Y f=15 9.29 F5 19 km/s HD 181147 DSCT HD 181555 Y f=15.4 14-17.5 c/d 8.74 A5 98 km/s HD 170782 DSCT HD 170580 N 13-25 c/d 7.81 A2 197 km/s HD 170699 DSCT HD 170580 N 10-15 c/d 6.95 A3 >200 km/s HD 172189 DSCT HD 171834 N 17-19 c/d EA +SB2 8.85 A2 48 and 75 HD 181555 DSCT primary target N 8-18 c/d 7.98 A5 170 km/s HD 49434 GDOR photometric variability elusive 5.75 F1 90 km/s HD 171834 GDOR no photometric variability 5.43 F5 72 km/s HD 180642 BCEP HD 181555 Y f=5.49 c/d f<10 c/d 8.29 B1 37 km/s HD 170580 BCEP no photometric variability, multiple system 6.68 B2V Target Type Field Frequencies V Sp V sin i Slide10:  Asteroseismology of FG Vir combining photometry and spectroscopy Mode identification (note how many axisymmetric modes) (Mantegazza and Poretti 2002) Feros data, rms residual on RV measurements : 0.32 km/s Slide11:  Evaluation of the inclination angle (FG Vir seen almost pole-on) See the waves propagate across the line profile (m number) Horizons opened by high resolution spectroscopy Slide12:  Spectroscopy of Gamma Dor variables High resolution spectra with ELODIE at OHP LPV variations clearly detected Incidence of binaries: 40-50% Mathias et al., 2003. Slide13:  Asteroseismology of the BCEP star Nu Eridani (Pamyatnykh et al. 2004) Data on rotational splitting of two dipole modes (g1 and l1) to infer properties of the internal rotation rate (three times faster than in the envelope) Slide14:  Preparatory work for DSCT, GDOR and BCEP Multicolour photometry : OSN, SPM, Mercator, Hungary, APT,… detection of predominant modes and frequency ranges low degree identification by phase shifts & amplitude ratios High resolution spectroscopy : OHP, SLN radial velocity curves characterization of GDOR (bright) variables LPV for BCEP and DSCT, but only bright stars All activities are running, but the resources are not sufficient to complement at best the COROT photomeric time-series Slide15:  …. one step beyond…. Use of more efficient instruments for spectroscopy FEROS at ESO (2.2m) HD 44195, HD 172189, HD 180642 ESPADONS at CFHT (4.0m) HD 44283, HD 50870, HD 188147 ELODIE/SOPHIE at OHP (2.2m) HD 49434, HD 171834, HD 170580 ……. Very long time baseline and intensive monitoring: not less than 15 nights per semester per observatory 4+8 targets only considering DSCT, GDOR, BCEP stars, but fast rotators (>150 km/s) still a problem Observations must be carried out in the framework of a LARGE PROGRAMME

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