A Pathway to Earth-like Worlds:

Transcription

1 A Pathway to Earth-like Worlds: Overcoming Astrophysical Noise due to Convection Dr. Heather Cegla!! Dr. Chris Watson, Dr. Sergiy Shelyag, Prof. Mihalis Mathioudakis

2 A Pathway to Earth-like Worlds: CoRoT ESPRESSO Kepler HARPS-N HARPS TESS PLATO 2.0 CHEOPS HIRES

3 Astrophysical Noise

4 Star spots, Plages Astrophysical Noise

5 Astrophysical Noise Star spots, Plages! Stellar Oscillations

6 Astrophysical Noise Star spots, Plages! Stellar Oscillations! Granulation

7 Astrophysical Noise Star spots, Plages! Stellar Oscillations! Granulation

8 Astrophysical Noise Star spots, Plages! Stellar Oscillations! Granulation! Variable Redshift Gravitational! Stellar Radius Change (%) km 100 km Mass (M O ) 50 km Mon. Not. R. Astron. Soc. 421, L54 L58 (2012) doi: /j x Stellar jitter from variable gravitational redshift: implications for radial velocity confirmation of habitable exoplanets H. M. Cegla, 1,2 C. A. Watson, 1 T. R. Marsh, 3 S. Shelyag, 1 V. Moulds, 1 S. Littlefair, 4 M. Mathioudakis, 1 D. Pollacco 1 and X. Bonfils 5 1 Astrophysics Research Centre, School of Mathematics & Physics, Queen s University Belfast, University Road, Belfast BT7 1NN, UK

9 Astrophysical Noise Star spots, Plages! Stellar Oscillations! Granulation! Variable Gravitational! Redshift

10 Current Removal Method Average out! the noise! ARTICLE Expensive!! Inefficient! Dumusque et al., 2011, A&A, 525, 140 Dumusque et al.: Stellar noise and planetary detection doi: /nature11572 An Earth-mass planet orbiting a Centauri B Xavier Dumusque 1,2, Francesco Pepe 1, Christophe Lovis 1, Damien Ségransan 1, Johannes Sahlmann 1, Willy Benz 3, François Bouchy 1,4, Michel Mayor 1, Didier Queloz 1, Nuno Santos 2,5 & Stéphane Udry 1 RADIALVELOCITYDETECTIONOFEARTH-MASS PLANETSINTHEPRESENCEOFACTIVITYNOISE: THE CASE CENTAURI Bb Exoplanets down to the size of Earth have been found, but not in the habitable zone that is, at a distance from the parent star at which water, if present, would be liquid. There are planets in the habitable zone of stars cooler than our Sun, but for reasons such as tidal locking and strong stellar activity, they are unlikely to harbour water carbon life as we know it. The detection of a habitable Earth-mass planet orbiting a star similar to our Sun is extremely difficult, because such a signal is overwhelmed by stellar perturbations. Here we report the detection of an Earth-mass planet orbiting our neighbour star a Centauri B, a member of the closest stellar system to the Sun. The planet has an orbital period of days and is about 0.04 astronomical units from the star (one astronomical unit is the Earth Sun distance) Since the discovery of the first exoplanet orbiting a solar-type star in Artie P. Hatzes artie@tls-tautenburg.de ThüringerLandessternwarte, D Tautenburg, Germany 0.04 astronomical units (AU). This planet, with a minimum mass sim- ived ; accepted

11 Our Removal Method

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13 Our Removal Method

14 Parameterisation Separate based on: Continuum Intensity Magnetic Field Four Components Granules Non-Magnetic! Intergranular Lanes Magnetic Intergranular Lanes MBPs Continuum Intensity Magnetic Field

15 Four Average Granulation Components (0 ) Flux Granules Non-Magnetic Lanes Magnetic Lanes MBPs Wavelength (Angstroms)

16 Original Reconstruct Best (0 ) 200 G Reconstruction Worst (0 ) Flux Avg Rel Err: Wavelength (Angstroms) Avg Rel Err: Wavelength (Angstroms)

17 Original Reconstruct Best (0 ) 50 G Reconstruction Worst (0 ) Flux Avg Rel Err: Wavelength (Angstroms) Avg Rel Err: Wavelength (Angstroms)

18 The Astrophysical Journal, 763:95(8pp),2013February C The American Astronomical Society. All rights reserved. Printed in the U.S.A. RV (m s -1 ) Granulation RVs from MHD Simulations doi: / x/763/2/95 0STELLAR SURFACE MAGNETO-CONVECTION AS A SOURCE OF ASTROPHYSICAL NOISE. I. MULTI-COMPONENT PARAMETERIZATION OF ABSORPTION LINE PROFILES -40 H. M. Cegla 1,2,S.Shelyag 1, C. A. Watson 1,andM.Mathioudakis Astrophysics Research Centre, School of Mathematics & Physics, Queen s University, University Road, Belfast BT7 1NN, UK; hcegla01@qub.ac.uk 0 2 Department20 of Physics & Astronomy, Vanderbilt University, 40 Nashville, TN 37235, USA 60 Received 2012 October 16; accepted 2012 December 1; published 2013 January 14 RV (m s -1 ) Recovered Granulation RVs from Parameterization Residuals RV (m s -1 ) Time (Minutes)

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21 Velocities Across the Disc 300 Original Reconstructed Oscillation 200 Velocity (m s -1 ) Inclination ( )

22 Generating New Profiles

23 Granule (0 ) (0 ) 1.0 CDF Non-magnetic Lane Filling Factor Granule CDF MBP (0 ) Filling Factor K-S Probability Method 1 Granules Non-Magnetic Lanes Magnetic Lanes MBPs Inclination ( )

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25 Analysing the Profiles V t V Normalised Flux V b C V V A b Wavelength (Angstroms)

26 Analysing the Profiles i+30 F 0 (i) RV(i) F 0 (i) RV(i) i i i Normalised Flux Velocity (km s 1 )

27 Initial Results

28 Initial Results

29 Initial Results

30 Initial Results Diagnostic V (cm s 1 ) Fractional Reduction (%) Pearson s R 20.4 BIS C V b A b bi-gauss V asy FWHM Line Depth EW Brightness

31 Next Steps... Continue to make observations more realistic:! Instrumental profile, photon noise, finite exposures, additional noise sources, various magnetic fields, injecting planets Test observationally! Solar data, highest RV precision targets Expand to a suite of stellar lines with varying:! Formation heights, absorption strengths,! excitation and ionisation potentials Expand to other spectral types