The Solar-like Light-curve Simulator (SLS) PLATO- PSM - WP R. Samadi

Transcription

1 The Solar-like Light-curve Simulator (SLS) PLATO- PSM - WP R. Samadi

2 In short Simulate stochastically-excited oscillations Include stellar granulation background, activity and white noise Applications (WP 120): Stellar science performance study Consolidation of the PLATO science case and preparation of the mission Hare and Hounds exercises Developed in Python Document: PLATO-LESIA-PSPM-TN-014, issue 1.1, sep. 2015

3 General principle Model of the expected PSD : P ( ν)=w + A ( ν)+g( ν)+o (ν) W : white noise ; A: activity ; G : granulation ; O : Oscillation spectrum Stochastic nature of the simulated phenomenon ( Anderson et al, 1990's approach): F ( ν)= P (ν) (U +i V ) U and V : two Normal distribution ; Hypothesis : uncorrelated phenomenon Simulated ligth-curve : inverse Fourier transform of F( ) Simulated PSD : P(ν)= F (ν) 2= P (ν) (U 2 +V 2 )

4 Granulation spectrum Two components (pseudo-lorentzian): hi G(ν)= i=1,2 1+(2 π τi ν)α i hi : height(s) i : characteristic time(s) i : slope(s) (Kallinger et al 2014) Origin of the two components not well established. Following Kallinger et al (2014) : Slopes fixed (=4) hi and i from scaling relations function of max Square of the total brightness fluctuations ( ²)

5 Granulation spectrum i : characteristic time Kallinger et al (2014) See also: Mathur et al (2011) Some theoretical supports: Ludwig (2006) Mathur et al (2011) Samad et al (2013 a&b) More details in Ludwig's talk i : characteristic amplitude

6 Oscillation spectrum Two types of oscillation spectra: Universal Pattern (UP, Mosser et al 2010) with mixed-modes Set of theoretical oscillation frequencies derived from a pulsation code (ADIPLS) O(ν)= i=1, N Li [ ν ] Resolved mode: Unresolved mode: Li (ν)= hi : mode height Hi 2 1+(2(ν νi )/ Γi ) i : mode frequency i : mode linewidth π Γi H i Li (ν)= sinc 2 [ π(ν νi )] 2δ ν

7 Universal pattern Following Mosser et al (2011) Additional term for dipole modes, asymptotic gravity-mode spacing (Mosser et al 2012) Mode amplitudes and line-widths: Gaussian envelope G (ν)=h max exp [ (ν ν max ) 2 δ ν2env / 4 ln 2 ] 2.38 H max =α ν max (Mosser et al 2013, SF2A) T eff Γ max =Γ K ( 10.8 ) (Belkacem 2012, SF2A)

8 Universal pattern Theoretical spectrum ( expectation ) Input parameters: - max - - Teff - q (coupling)

9 Set of theoretical mode frequencies Theoretical adiabatic frequencies : as given by ADIPLS Spilling : constant (Ledoux's constant from ADIPLS) Surface effects : Lorentzian component (Sonoi et al 2015) 2 free input parameters (a,b) Amplitudes : observationnal scaling relation from Corsaro et al (2013) Line-widths : observationnal scaling relation from Appourchaux et al (2012) A typical PLATO target

10 Illustration Granulation Oscillations Activity component not sown in this illustration White noise

11 Illustration PLATO application V = 10.5

12 Conclusion and perspectives Easy to install and use, fast Free access for PLATO consortium members More realistic mode line-widths variation with frequency (e.g. results from non-adiabatic pulsations) ; Prescription for the parameters of the activity component ; Realistic instrumental effects ( red noise, periodic perturbations,.) ; Account for weighted mask photometry (as function of the star position and intensity) ; Simulation of independent camera (time delays ; different PSF).

13 Additional slides

14 Predicted instrumental red noise

15 Observational scaling relation of mode amplitudes Corsaro et al (2013)

16 Universal pattern Granulation Oscillations Simulated spectrum (for a given realization) White-noise