RUPRECHT-KARLS-UNIVERSITÄT HEIDELBERG DOCTORAL THESIS Perspectives of the Radial Velocity Method: Physical Modeling of the Wavelength Solution & Exoplanetary Detections around Giant Stars Author: Supervisor: Marcelo Said TALA PINTO Prof. Dr. Andreas QUIRRENBACH Second Referee: Prof. Dr. Thomas HENNING Thesis submitted in fulfillment of the requirements for the degree of Doctor of Natural Sciences in the Extrasolar Planet Research Group Landessternwarte Königstuhl June 4, 2019 ii iii Dissertation in Astronomy submitted to the Combined Faculties of the Natural Sciences and Mathematics of the Ruperto-Carola-University of Heidelberg, Germany for the degree of Doctor of Natural Sciences M.Sc. Marcelo Said Tala Pinto Born in Antofagasta, Chile Oral Examination: 16.07.2019 iv v Perspectives of the Radial Velocity Method: Physical Modeling of the Wavelength Solution & Exoplanetary Detections around Giant Stars Referees: Prof. Dr. Andreas Quirrenbach Prof. Dr. Thomas Henning vi vii “Even if all life on our planet is destroyed, there must be other life somewhere which we know nothing of. It is impossible that ours is the only world; there must be world after world unseen by us, in some region or dimension that we simply do not perceive. Even though I can’t prove that, even though it isn’t logical - I believe it, he said to himself ” The Man in the High Castle - Philip K. Dick, 1962 viii ix Abstract First, I present the design and construction of the Front-end of the Waltz Spectro- graph. I designed upgrades in the system to optimize its mechanical stability and light coupling efficiency. To improve the instrument performance, I changed the original spectrograph fiber for one with slightly larger core and better focal ratio degradation, providing a spectral resolving power of 60.000, a mean spectral sam- pling of 2.6 pixels and only 5 % losses due to focal ratio degradation. In the second part I present a ray tracing software that calculates the optical path of individual rays through an echelle spectrograph from the slit to the detector. By including the effects of the environment on the physical properties of the optical elements that compose the spectrograph, I am able to reproduce some of the trends observed in the time series of the spectral line positions of the calibration data. Finally, I report the discovery of two planets orbiting the stars HD 25723 and 17 Sco and two planet candidates orbiting 3 Cnc and 44 Uma. Also, I investigate the planet occurrence rates as a function of evolutionary stage for two surveys, Lick and EXPRESS, concluding that there is no strong effect of stellar evolution in planet occurrence rates. Zusammenfassung Als erstes präsentiere ich das Design und die Konstruktion des Waltz Spektro- grafen Frontends. Ich entwarf Verbesserungen im System seine mechanische Sta- bilität und Lichtkopplungseffizienz zu optimieren. Mit dem Ziel die Leistung des Instruments zu erhöhen, habe ich die ursprüngliche Glasfaser des Spektrografen gegen eine mit einer geringeren Degradierung des Fokusverhältnisses und einem etwas größeren Kern ausgetauscht. Das neue Design erreicht eine spektrale Au- flösung von 60.000, eine spektrale Abtastrate von durchschnittlich 2.6 Pixeln sowie lediglich 5% Verlust durch die Degradierung des Fokusverhältnisses. Im zweiten Teil präsentiere ich eine Lichtstrahlverfolgungssoftware, welche den Weg einzelner Lichtstrahlen durch einen Gitterspektrografen vom Spalt bis zum Detektor berechnet. Indem ich die Umwelteinflüsse auf die physikalischen Eigen- schaften der optischen Elemente des Spektrografen miteinbeziehe, kann ein ein paar der Verläufe reproduzieren, welche in Zeitreihen der Spektrallinienpositionen der CARMENES Kalibrationsdaten vorhanden sind. Zuletzt gebe ich die Entdeckung zweier Planeten um die Sterne HD 25723 und 17 Sco sowie zweier Planetenkandidaten um 3 Cnc und 44 UMa bekannt. Zusät- zlich untersuche ich die Planetenhäufigkeit in Abhängigkeit des evolutionären Sta- tus zweier Beobachtungsprogramme: Lick und EXPRESS. Mittels der abgeleiteten Planetenhäufigkeit kann ich schlussfolgern, dass die Evolutionsphase des Sterns keinen starken Einfluss auf die Planetenhäufigkeit hat. xiii Acknowledgements Long time ago, when my mother took me to the Paranal Observatory, close to my home city Antofagasta, I never thought that I was going to end up doing my PhD in the observatory that built the first optical instrument for the VLT1. Learning Astron- omy at the Landessternwarte Königstuhl is one of the greatest treasures of my life, and I will always be thankful to my supervisors, Prof. Dr. Andreas Quirrenbach and Priv.-Doz. Sabine Reffert, for giving the opportunity to pursue my doctoral studies in such a rich scientific environment. Just in the LSW it would have been possible to become the best astronomer I can be, and this is mostly because of your support and the freedom you gave me to explore the nature of my scientific work. I would like to thank to all the people who contributed with their work to the completion of this thesis: Anantha Chanumolu who guided me through the con- struction of the RAMSES code by giving me parts of her code and providing feed- back during the course of this investigation, Lutz Geuer and Ludwig Schäffner for their excellent work at the LSW Workshop building the parts for the Waltz and for the excellent feedback provided when I had to improve my mechanical designs, Wal- ter Seifert and Conchi Cárdenas for providing the optical designs of the CARMENES VIS and NIR spectrographs as built, Otmar Stahl for the discussions about the envi- ronment control system of CARMENES and for solving all most my IT issues dur- ing the last four years, Julian Stürmer and Christian Schwab for the discussions that helped improving the original design of the Waltz Spectrograph, and Matthias Zech- meister and Florian Bauer for providing the data I used to analyze the behaviour of CARMENES and for all the fruitful discussions that helped me understand what really a wavelength solution is. The progress in science has never been a task of one, as the cornerstone of a succesful learning process is the exchange of knowledge and ideas with our friends and colleagues. As far as I am from home now, curiously, home never really felt far away and this is thanks to the Exoplanets and Astrophotonics Research Groups at the LSW: Theodorus Anagnos, Paz Bluhm, Stefan Brems, Robert Harris, Paul Heeren, Philip Hottinger, Adrian Kaminski, Jonas Kemmer, Sepideh Sadegi, Dane Späth, Stephan Stock, Thomas Stuber, Trifon Trifonov, Vera Wolthoff and Steffi Yen. A special tribute deserves Steffi and Rob, as we started our respective science trips in Heidelberg more or less at the same time and have played an important role in my doctoral studies, but also in the quality of the english of this thesis. Without their friendship the days in Heidelberg would have not been so colorful. A special tribute goes to Vera and Stefan for their contribution in the german translation of the abstract. It is the time to put the final points to this thesis. Before doing so I must em- phasize that most of what I am as a scientist and human being was learned from 1Appenzeller et al. 1998, "Successful commissioning of FORS1 - the first optical instrument on the VLT." xiv my family, my mother Ana María Pinto Castillo and my brothers, Maximiliano Tala Pinto and Marco Tala Pinto. Even though none of them is a scientist, they planted in me the seed of curiosity, but more important, the seed of honesty and kindness. And those are, in my opinion, the three qualities that a good scientist must have. To be curious, to be honest, and to be kind. To you, who are reading these words now. Thank you. xv Contents Abstract ix Zusammenfassung xi Acknowledgements xiii 1 Introduction1 1.1 Exoplanets...................................1 1.2 The Radial Velocity Method.........................3 1.2.1 High Resolution Spectroscopy for Precise Radial Velocities...5 1.2.2 The Iodine Cell Technique......................9 1.2.3 The Simultaneous Calibration Technique............. 11 1.3 The Lick Survey of Giant Planets around Giant Stars........... 13 1.4 CARMENES: a search for Super-Earths around M-dwarfs........ 14 1.5 Objectives and Outline............................ 17 2 Front-end opto-mechanical design of the Waltz Telescope 19 2.1 Introduction.................................. 19 2.2 Instrument description............................ 20 2.2.1 Spectrograph optical design..................... 20 2.2.2 Calibration Unit............................ 22 2.3 FN-system and Spectrograph Fiber upgrade............... 23 2.3.1 FN-system............................... 24 2.3.2 Focal Ratio Degradation....................... 26 Experimental setup.......................... 26 Measurement procedure....................... 26 Results................................. 28 2.3.3 Final spectrograph optical design.................. 28 2.4 Waltz Front-end................................ 29 2.4.1 Preliminary design.......................... 30 Early results.............................. 32 2.4.2 Waltz Telescope F/#......................... 34 Experimental procedure and results................ 34 2.4.3 Final Waltz Front-end Opto-mechanical Design......... 36 Calibration Fiber........................... 36 Fiber Aperture on-sky and Mirror Pinhole............ 36 xvi Fiber Feeding Unit.......................... 38 Final Design.............................. 40 2.4.4 Front-end control........................... 42 2.5 Summary.................................... 43 3 RAMSES and the CARMENES wavelength