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RECIBIDO Conicyi PONTIFICIA UNIVERSIDAD CATÓLICA DE CHILE FACULTAD DE FÍSICA DEPARTAMENTO DE ASTRONOMÍA Y ASTROFÍSICA TOWARDS RüCKY PLANETS USING THE PLANET FINDER SPECTROGRAPH BY PAMELA V. ARRIAGADA P. Thesis presented to the Department of Astronomy and Astrophysics of the Pontificia Universidad Católica de Chile to obtain the degree of PhD in Astrophysics. Advisors: Dante Minniti (PUC) and R. Paul Butler (CIW, DTM) Readers: Andrés Jordán (PUC), Patricia Arévalo (UNAB), Julio Chanamé (PUC) and Gaspar Galaz (PUC) -- _, ......... __ ........,._ 1 RECIBIDO CONICYi PROGRAMA CAPITAL HUMANO AVANZAO'J July, 2012 2 o SEP 2012 Santiago, Chile @2012, Pamela Arriagada HORA: ____~-- FIRMA: ~tr ZDlZ @2012, Pamela Arriagada. Se autoriza la rer,..ToducciÓJJ total o pctrcia.l, co11 fi11es académicos, por C:lmlquier medio o procedimiento, incluyendo la cita bil1liográfica del documento. Acknowledgments First, I would like to thank my supervisors, R. Paul Butler and Dante Minniti. Paul has been the most fun and caring mentor. He has always trusted in my work, thank you for guiding me during this process. Dante has been the most understand­ ing supervisor, thank you for making this journey a non-stressful one. I would also like to thank the Magellan Planet Search Team: Stephen Shectman, Jeff Crane and Ian Thompson, for allowing me to be part of the Planet Finder Spectrograph team. I also grateful to all the other collaborators who have put time and effort in the project : Guillem Anglada-Escudé, Steve Vogt, Eugenio Rivera, James J enkins and Erad Carter. I wouldn't like to forget the staff at Las Campanas: Don Tito and the kitchen staff, who have prepared wonderful meals and beautiful desserts for us on the moun­ tain, always with a smile on their faces; the telescope operators, who have prevented me from falling asleep during our long observing runs and pretended to like the music I listened to, I couldn't have observed anything without them; the technical and engineering staff, who kecp thc tclescope working and did not let me break PFS when somehow, I was involved in the task of dismounting it. I am obliged to my fellow postgraduate students and friends Paula and Pía, who have had to put up with my craziness for the past 3 years. To my friends at the Theoretical Physics department Tío :Miguel, Bastin and Diego for our enlightening conversations during lunch hours. I'd like to acknowledge CONICYT (Comisión Nacional de Investigación de la Científica y Tecnológica) for having support me financially during my studies. I am also grateful to the Department of Astronomy at Católica for the MECESUP grant which allowed me to spend two months working with Paul at the Carnegie Institution of Washington in Washington DC. This work was also partially funded by the Fondap Center for Astrophysics Nr. 15010003 and by the BASAL Center for Astrophysics and Applied Technologies Nr. 0609. Finally, I want to thank my family: Ivonne, Gustavo, Nacho, Blibli, Claudia, and Matias, for pushing me in every step of the way. Contents Resumen ix Abstract XI 1 Introduction 1 1.1 Doppler veloci ty technique 2 1.2 Planets arouncl M clwarfs . 5 1.3 M clwarfs ancl Planet formation 5 1.4 Habitability ancl 'f}Earth 6 1.5 Thesis outline . 8 2 Chromospheric Activity of Southern Stars 9 2.1 Introcluction ........... 9 2.2 Observations ancl elata recluction . 10 2.3 Analysis ............. 12 2.3.1 Derivation of S índices from MIKE/lVIagellan observations 12 2.3.2 Converting from s~HKE to Mount \Vilson s~d\N 13 2.3.3 Uncertainties ancl ranclom errors . 13 2.3.4 log R;rK . · · · · 14 2.3.5 Rotation periocls ancl Ages 15 2.3.6 Radial velocity jitter 16 2.4 Conclusions ........ 17 3 A new deconvolution routine for M-dwarfs 24 3.1 Introcluction . 24 3.2 Keck/HIRES observa.tions 25 3.3 The role of Deconvolution in Doppler Analysis 26 3.4 Deconvolution algorithms 27 3.4.1 The problem of deconvolution 27 3.4.2 J ansson technique . 28 3.4.3 The Bayesian approach 29 3.4.4 The least squares method using B-splines 31 3.4.5 Comparison of various deconvolution routines on Keck/HIRES template spectra 32 3.5 Results . 35 3.6 Conclusions 36 4 The Magellan Planet Search 44 4.1 Introduction ........ 44 4.2 The Old Magellan Planet Search 45 4.2.1 New exoplanets ..... 45 4.3 The New Magellan Planet Search 47 4.3.1 Targets ......... 47 4.4 Observations and data reduction . 48 4.5 S values . 49 4.5.1 PFS Caii H index. 49 4.5.2 From SPFS to SMw 49 4.6 Velocity Precision ..... 51 4.7 Preliminary results . 51 4.7.1 A planetary system around the nearby M dwarf GJ 667C with one super-Earth in its habitable zone ............ 51 4.7.2 Two planetary companions to the Nearby M dwarf GJ 221 57 4.8 Summary .......... 65 5 Conclusions and Future Work 71 5.1 Summary and conclusions 71 5.2 Ongoing and future work . 73 Bibliography 75 ll List of Tables 3.1 Resulting uncertainties using each of the deconvolution algorithms for each star: Jansson, Boosted 1VIaximum Likelihood (BJ\!IL), Damped Richardson-Lucy (DRL), lVIaximum Entropy (ME) ancl B-Splines de­ convolution (Decosp). The three rows for each star correspond to the RMS of all velocities (top), RMS of velocities averaged in 2-hour bins 1 (middle) ancl interna! errors (bottom). These are given in m s- . 38 1 1 3.2 Velocity dispersion in m s- of stable (RiviS< 6 m s- ) J\!I-dwarfs from the California-Carnegie Planet search. The four left columns show the RJ\!IS obtained using all observations (including interna!). The four columns on the right, show the RlVIS obtained using only post-fix (taken with improved CCD mosaic) observations (including interna!). 41 4.1 Stellar Properties 65 4.2 Best Keplerian solution to the planetary system around GJ 667C. The numbers in parenthesis indicate the uncertainty in the last two siguificant digits of thc paramctcr valucs. Uuccrtaiutics havc bccn obtained using a Bayesian lVIGMC analysis (Ford 2005) and represent the 68% confidence levels around the preferred solution. All orbital elements are referred to JD0 = 2453158.7643. The assumed mass of GJ 667C is 0.31 lVLz. 67 4.3 Best Keplerian solution to the planetary system around GJ 221. The numbers in parenthesis indicate the uncertainty in the last two sig­ nificant digits of the parameter values. Uncertainties correspond to the standard deviation of the ma.rginalized MCMC samplings. The assumed mass of GJ 221 is 0.77 l\(.. 68 iii 1 Derived S-values from MIKE spectra converted to MW system, SvuKE; chromospheric activity índices, log R~K ; rotation periods, Pro,; ages, log(Agejyears); and estimated jitter, o-~v (Isaacson & Fischer (2010) and Wright (2005)) labeled as 1 and 2 respective! y. 84 lV List of Figures 1.1 Orbital elements 3 1.2 The orbital region that remaim; continuously habitable during at least 5 Gyr as a function of the stellar mass. Dark gray and light gray areas show the Habitable Zone defined using different criteria (see Selsis et al. 2007 for a more detailecl clescription). The dotted bound­ aries corresponcl to the extreme theoreticallimits, found with a 100% cloucl cover. The clashed line inclicates the clistance at which a 1 IVIEart.h planet on a circular or·bit becomes tidally locked in less than 1 Gyr. Figure from Selsis et al. 2007 . 7 2.1 V, K, H ancl R channels in a representative l\IIIKE spectrum. The relative flux is in arbitrary units. vVavelengths have been shiftecl to zero velocity in orcler to make the measurements. 18 2.2 Comparison between sl\HKE measnrements t.aken in clifierent. epochs. In the left panel, fillecl circles correspond to measured S values using data taken between May 2004 and Sept. 2005 vs. S measured using data taken after Sept. 2005. The solid line corresponcls to a linear regression, yielcling a slope of 0.995 and an intercept of -0.002. In t.he right. panel, filled circles correspond Lo mea:mred S valnes nsing data taken before May 2004 vs. measured using data taken after Sept. 2005. The solid line corresponcls to a linear regression, yielcling a slope of 0.987 andan intercept of -0.011. 19 V 2.3 Comparison between SMIKE measurements with previous measure­ ments that are already calibrated to the S,,1w system. Solid lines correspond to linear regressions for each of the datasets, while the dashed lines show relations of slope unity. For clarity, the Jenkins et al (2008), Henry et al. (1996) and Gray et al. (2006) datasets have an offset of 0.4, 0.8 and 1.2 respedively . 20 2.4 Upper panel : Comparison between log R~K indices obtained from MIKE spectra in this work and those obtained from FEROS spectra by Jenkins et al. (2008). The line denotes a 1:1 relationship. Lower panel : the level of difference between both samples, or rY values vs. our log R~K indicies. The line denotes O level of difference between the samples. 21 2.5 Top: T Ceti S-values from Magellan/MIKE to illustrate my measure­ ment errors, in contrast with the 1% scatter obtained at Mount Wil­ son. MIKE Observations have a standard deviation of 4.9%, consistent with what has been previously obtained at Keck and Lick (Wright et al. 2005). Bottom: Chromospherically active star, HD 219764, S­ values show a 0.07 dex standard deviation (7%) in contrast to Tau Ceti, 0.008 dex.
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