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Ground Based Photometry

Ground Based Photometry. S.O. Kepler Brazil. Photometry. Single Channel Two channel: star + comparison Three channel: star+comparison+sky CCD: star + comparisons + skies g-modes in Earth’s atmosphere diffraction rings. CCD. Flat field SNR=1000 : 100 flats at 1% linearity

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Ground Based Photometry

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  1. Ground Based Photometry S.O. Kepler Brazil

  2. Photometry • Single Channel • Two channel: star + comparison • Three channel: star+comparison+sky • CCD: star + comparisons + skies • g-modes in Earth’s atmosphere • diffraction rings

  3. CCD • Flat field SNR=1000 : 100 flats at 1% linearity • At least 2 comparisons stars, bright • Autoguide • Frame transfer or low duty cycle or windowing • Precise timings • Quantum efficiency and altitude variation affect Amp.

  4. Chromatic amplitude changes SX Phe, Rodriguez et al.

  5. Data reduction • Timings for barycenter of the solar system • Leap second corrections • Extinction correction • Optimum extraction: aperture vs seeing

  6. Multiperiodic Herbig Ae star, Bernabel et al.

  7. Fourier Transforms • Noise not poissonic • Data not equally spaced • Need Monte Carlo simulation for false alarm probability • Identification of multiple modes: pre-whitening

  8. Large telescope, small amplitudes 4.1m 2.1m Frequency

  9. Low amplitude pulsators

  10. b Cep

  11. G117-B15A: DAV Teff = 12000K Distance Parallax 95 + 37 pc Optical Spectra 58 + 02 pc IUE flux 59 + 05 pc HST flux 67 + 04 pc Seismology Bradley 1998 61pc Seismology Benvenutto et al. 2002 63 pc Mean: 67 + 14 pc 215s 304s 270s 107s 119s 125s

  12. Eclipsing pulsators PG1336-018, Maia Vuckovic Vik Dhillon, Stuart Littlefair, and Paul Kerry (Sheffield, UK), Tom Marsh (Warwick, UK), Andy Vick and Dave Atkinson (UKATC, Edinburgh, UK)

  13. Stephi: 3-site Delta Scuti

  14. Delta Scuti Network

  15. DSN Campaigns • DSN 1 Theta 2 Tauri1983 • DSN 2 4 CVn 1984 • DSN 3 Theta 2 Tauri 1986 • DSN 4 HR729 1988 • DSN 5 BU Cnc & EP Cnc 1989 • DSN 6 63 Her 1990 • DSN 7 HN CMa 1990 • DSN 8 CD -24 7599 1992 • DSN 9 FG Vir1993 • DSN 10 IC 418 1993 • DSN 11 CD -24 7599 1994 • DSN 12 Theta 2 Tauri 1994 • DSN 13 IC 418 1994 • DSN 14 FG Vir1995 • DSN 15 4 CVn1996 • DSN 16 4 CVn1997 • DSN 17 CD -24 7599 1998 • DSN 18 BI CMi 1998/1999 • DSN 19 BI CMi 1999/2000 • DSN 20 44 Tau 2000 • DSN 21 44 Tau 2001 • DSN 22 FG Vir2002 • DSN 23 FG Vir2003 • DSN 24 44 Tau 2003 • DSN 25 FG Vir2004, 79 freqs • DSN 26 44 Tau 2004 • DSN 27 HD210111 & ,AS Eri 2005 • DSN 28 UV Oct & SS For 2005 • DSN 29 44 Tau 2005

  16. Delta Scuti

  17. Whole Earth Telescope

  18. Whole Earth Telescope • XCov1 Mar 1988 *PG 1346+082* IBWD Winget, Provencal • V803 Cen IBWD O'Donoghue • XCov 2 Nov 1988 *G29-38* DAV Winget • V471 Tau ICBS Clemens • XCov 3 Mar 1989 *PG 1159-035* GW Vir Winget • XCov 4 Mar 1990 *AM CVn* IBWD Solheim, Provencal • G117-B15A DAV Kepler • XCov 5 May 1990 *GD358* DBV Winget • GD165 DAV Bergeron • HD 166473 roAp Kurtz • XCov 6 May 1991 *PG 1707* GW Vir Clemens, Pfeiffer • GD154 DAV Vauclair • XCov 7 Feb 1992 *1H0857* CV Buckley • PG 1115 DBV Barstow, Clemens • G226-29 DAV Kepler • WET-0856 d Scu Breger, Handler • XCov 8 Sep 1992 *PG 2131+066* GW Vir Kawaler, Nather • G185-32 DAV Moskalik • RX J2117 GW Vir Vauclar, Moskalik • XCov 9 Mar 1993 *PG 1159-035* GW Vir Winget • *FG Vir* d Scu Breger • XCov 10 May 1994 *GD358* DBV Nather, Bradley • XCov 11 Aug 1994 *RX J2117* GW Vir Vauclar, Moskalik • XCov 12 Apr 1995 *PG 1351* DBV Hansen • L19-2 DAV Sullivan, Clemens • XCov 13 Feb 1996 *RE 0751+14* CV Marar, Seetha • CD-24 7599 d Scu Breger, Handler • XCov 14 Sep 1996 *PG 0122+200* GW Vir O'Brien • WZ Sge CV Nather • XCov 15 Jul 1997 *DQ Her* CV Nather • EC 20058 DBV O'Donoghue • XCov 16 May 1998 *BPM 37093* DAV Kanaan, Kepler • XCov 17 Apr 1999 *PG 1336* sdB Kilkenny • *BPM 37093* DAV Kanaan, Kepler, Nitta, Winget • XCov 18 Nov 1999 *HL Tau 76* ZZ Ceti Dolez, Vauclair, Kleinman • PG 0122 DOV Vauclair, O'Brein • XCov 19 June 2000 *GD358* DBV Kepler, Nitta • XCov 20 Nov 2000 *HR 1217* roAp Kurtz • KUV 05134+2605 DBV Handler, Nitta • R 548 ZZ Ceti Mukadam • XCov 21 Apr 2001 *PG 1336* sdb Reed, Kilkenny • PG 1654-160 DBV Handler • Feige 48 sdB Reed, Kawaler • Mrk 501 AGN Miller, Krennrich • Xcov 22 May 2002 *PG 1456+103* DBV Handler • PG 1159-035 GW Vir O'Brein • Feige 48 sdB Reed, Kawaler • PG 1605+072 sdB Schuh, et. al, & MSST • XCov 23 Aug 2003 *KPD 1930+2752* sdB Charpinet, Reed • G 29-38 DAV Kleinman • HS 2201+2610 sdB Silvotti • XCov 24 Oct 2004 *PG 0014* sdB Kawaler • RX J2117 GW Vir Moskalik • XCov 25 Jul 2006 GD358 DBV Provencal • XCOV 26 Mar 2008 EC14012-114 DAV Montgomery • PG1159-035 DOV Costa

  19. roAp Don Kurtz Margarida Cunha

  20. White dwarfs

  21. GD 358 light curve in 1996

  22. PG1159-035 k=14 - 42 -no harmonics or combination modes -no convection zone - 198 modes: 29 triplets, 46 quintuplets J. Edu S. Costa

  23. PG1159-035 DP=21.43+0.05s M=0.586+0.001MSun Period(s)

  24. Measure thickness of envelope Córsico et al. 2008

  25. E(cycles) dP/dt=(+10.6+0.1)x10-11 s/s

  26. d2P/dt2

  27. Costa & Kepler 2008: rotation, contraction rates, cooling rates • dP/dt • dPRotation/dt • dR/dt • dT/dt

  28. Average multiplets i=70o

  29. Rotation effects • Multiplets have different amplitudes • Amplitudes change (energy exchange with rotation?) • Gough: “Only when the star is rotating is there a physically real principal axis …with a well defined directed orientation … So if there is an m = +1 , m = −1 asymmetry … it has to be a consequence of rotation.”

  30. Measure evolution and core composition ZZ Ceti white dwarf

  31. ZZ Cetis

  32. Combination frequencies Mike Montgomery

  33. Castanheira & Kepler 2008 Hydrogen layer mass

  34. Questions on mode properties • What are the driving, mode selection, and amplitude limiting mechanism(s)? • Are they the same for all strips and throughout each strip? • What is the cause of the amplitude and phase changes on timescales from weeks to years? • What is the origin, role, and nature of mode coupling? • What is the role of inclination in m-selection, considering we see the amplitude of different m components change with time in a few stars? • Can we measure the velocity and line profile variations needed for mode identification, necessary for full asteroseismic analysis? • Are there other values of the spherical harmonic degree, besides 1 and 2 already observed in white dwarfs? High l have been identified in sd. • Is driving different for different pulse shapes, or for the DOVs, where the models do not indicate significant convection? • Can we identify the modes with chromatic amplitude and combination peaks?

  35. Low amplitudes: AnjumMukadam 2008

  36. Mode identification

  37. That’s all folks!

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