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 At least 2 comparisons stars, bright Autoguide Frame transfer or low duty cycle or windowing Precise timings Quantum efficiency and altitude variation affect Amp.

Chromatic amplitude changes SX Phe, Rodriguez et al.

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

Multiperiodic Herbig Ae star, Bernabel et al.

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

Large telescope, small amplitudes 2.1m 4.1m Frequency

Low amplitude pulsators

 Cep

Distance Parallax pc Optical Spectra pc IUE flux pc HST flux pc Seismology Bradley pc Seismology Benvenutto et al pc Mean: pc 215s 270s 304s 107s 119s 125s G117-B15A: DAV T eff = 12000K

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

Stephi: 3-site Delta Scuti

Delta Scuti Network

DSN Campaigns DSN 1 Theta 2 Tauri 1983Theta 2 Tauri DSN 2 4 CVn CVn DSN 3 Theta 2 Tauri 1986Theta 2 Tauri DSN 4 HR HR729 DSN 5 BU Cnc & EP Cnc 1989BU Cnc & EP Cnc DSN 6 63 Her Her DSN 7 HN CMa 1990HN CMa DSN 8 CD CD DSN 9 FG Vir 1993 FG Vir DSN 10 IC IC 418 DSN 11 CD CD DSN 12 Theta 2 Tauri 1994Theta 2 Tauri DSN 13 IC IC 418 DSN 14 FG Vir 1995 FG Vir DSN 15 4 CVn CVn DSN 16 4 CVn CVn DSN 17 CD CD DSN 18 BI CMi 1998/1999BI CMi DSN 19 BI CMi 1999/2000BI CMi DSN Tau 2000 DSN Tau 2001 DSN 22 FG Vir 2002 FG Vir DSN 23 FG Vir 2003 FG Vir DSN Tau 2003 DSN 25 FG Vir 2004, 79 freqs FG Vir DSN Tau 2004 DSN 27 HD &,AS Eri 2005HD &,AS Eri DSN 28 UV Oct & SS For 2005UV Oct & SS For DSN Tau 2005

Delta Scuti

Whole Earth Telescope

XCov1 Mar 1988 *PG * 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 * 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 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 G DAV Kepler WET-0856 d Scu Breger, Handler XCov 8 Sep 1992 *PG * GW Vir Kawaler, Nather G DAV Moskalik RX J2117 GW Vir Vauclar, Moskalik XCov 9 Mar 1993 *PG * 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 * CV Marar, Seetha CD d Scu Breger, Handler XCov 14 Sep 1996 *PG * GW Vir O'Brien WZ Sge CV Nather XCov 15 Jul 1997 *DQ Her* CV Nather EC 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 DBV Handler, Nitta R 548 ZZ Ceti Mukadam XCov 21 Apr 2001 *PG 1336* sdb Reed, Kilkenny PG DBV Handler Feige 48 sdB Reed, Kawaler Mrk 501 AGN Miller, Krennrich Xcov 22 May 2002 *PG * DBV Handler PG GW Vir O'Brein Feige 48 sdB Reed, Kawaler PG sdB Schuh, et. al, & MSST XCov 23 Aug 2003 *KPD * sdB Charpinet, Reed G DAV Kleinman HS 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 EC DAV Montgomery PG DOV Costa

roAp Don Kurtz Margarida Cunha

White dwarfs

GD 358 light curve in 1996

k= J. Edu S. Costa PG no harmonics or combination modes -no convection zone modes: 29 triplets, 46 quintuplets

Period(s) PG  P= s M = M Sun

Measure thickness of envelope Córsico et al. 2008

dP/dt=( )x s/s E(cycles)

d 2 P/dt 2

Costa & Kepler 2008: rotation, contraction rates, cooling rates dP/dt dP Rotation /dt dR/dt dT/dt

Results dP/dt (516s)= 1ms/yr = ( )x s/s, (517s)=( )x s/s, (539s)=( )x s/s d 2 P/dt 2 =( )x s/s, (517s)=( ) s/s P rotation = d dP rot /dt=( )x10 -6 s/s dR/dt=( )x s/s dT/dt=( )x s/s Trapping at 0.83R * +   P(l=1)= s M= M Sun  P(l=2)= s B<2000G

Average multiplets i=70 o

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.”

Measure evolution and core composition ZZ Ceti white dwarf

DBVs

ZZ Cetis

Combination frequencies Mike Montgomery

Hydrogen layer mass Castanheira & Kepler 2008

White dwarf pulsations Pulsations are global and sample almost the whole interiors of white dwarf stars. The seismologically determined masses are more accurate than those obtained from binary solutions. Asteroseismology is the only tool to measure the surface layer masses, which are determined from the up-to-now not accurately modeled mass loss through stellar evolution. Asteroseismology can determine the core composition of white dwarf stars and help to measure the C(  )O reaction rate that cannot be measured in a terrestrial laboratory. Asteroseismology can accurately measure the nature and extent of surface partial ionization zones and probe convective energy transport. The rates of change of the pulsation periods are measurable and can be used to precisely measure the evolutionary rates of these old stars, to detect planets around them, and to probe for exotic particles that are strong candidates for dark matter.

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?

Low amplitudes: Anjum Mukadam 2008

Mode identification

That’s all folks!