Perspectives of the Radial Velocity Method: Physical Modeling of the Wavelength Solution & Exoplanetary Detections around Giant Stars

First, I present the design and construction of the Front-end of the Waltz Spectrograph. 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 sampling 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

New HARPS and FEROS observations of GJ1046

In this paper we present new precise Doppler data of GJ1046 taken between November 2005 and July 2018 with the HARPS and the FEROS high-resolution spectographs. In addition, we provide a new stellar mass estimate of GJ1046 and we update the orbital parameters of the GJ1046 system. These new data and analysis could be used together with the GAIA epoch astrometry, when available, for braking the $\sin i$ degeneracy and revealing the true mass of the GJ1046 system.Comment: 2 pages, 1 figure, 1 table with RV data (available only in the Astro-PH version of the paper), Accepted by RNAA

18 Sco: A solar twin rich in refractory and neutron-capture elements. Implications for chemical tagging

We study with unprecedented detail the chemical composition and stellar parameters of the solar twin 18 Sco in a strictly differential sense relative to the Sun. Our study is mainly based on high-resolution (R ∼ 110,000), high signal-to-noise ratio (80

High precision abundances of the old solar twin HIP 102152: Insights on Li depletion from the oldest sun

We present the first detailed chemical abundance analysis of the old 8.2 Gyr solar twin, HIP 102152. We derive differential abundances of 21 elements relative to the Sun with precisions as high as 0.004 dex (≲1%), using ultra high-resolution (R = 110,0

Three Warm Jupiters around Solar-analog Stars Detected with TESS*

We report the discovery and characterization of three giant exoplanets orbiting solar-analog stars, detected by the TESS space mission and confirmed through ground-based photometry and radial velocity measurements taken at La Silla observatory with FEROS. TOI-2373 b is a warm Jupiter orbiting its host star every ∼13.3 days, and is one of the most massive known exoplanet with a precisely determined mass and radius around a star similar to the Sun, with an estimated mass of m _p = ${9.3}_{-0.2}^{+0.2}\,{M}_{\mathrm{jup}}$ and a radius of r _p = ${0.93}_{-0.2}^{+0.2}\,{R}_{\mathrm{jup}}$ . With a mean density of $\rho ={14.4}_{-1.0}^{+0.9}\,{\rm{g}}\,{\mathrm{cm}}^{-3}$ , TOI-2373 b is among the densest planets discovered so far. TOI-2416 b orbits its host star on a moderately eccentric orbit with a period of ∼8.3 days and an eccentricity of e = ${0.32}_{-0.02}^{+0.02}$ . TOI-2416 b is more massive than Jupiter with m _p = ${3.0}_{-0.09}^{+0.10}\,{M}_{\mathrm{jup}}$ , however is significantly smaller with a radius of r _p = ${0.88}_{-0.02}^{+0.02},{R}_{\mathrm{jup}}$ , leading to a high mean density of $\rho ={5.4}_{-0.3}^{+0.3}\,{\rm{g}}\,{\mathrm{cm}}^{-3}$ . TOI-2524 b is a warm Jupiter near the hot Jupiter transition region, orbiting its star every ∼7.2 days on a circular orbit. It is less massive than Jupiter with a mass of m _p = ${0.64}_{-0.04}^{+0.04}\,{M}_{\mathrm{jup}}$ , and is consistent with an inflated radius of r _p = ${1.00}_{-0.03}^{+0.02}\,{R}_{\mathrm{jup}}$ , leading to a low mean density of $\rho ={0.79}_{-0.08}^{+0.08}\,{\rm{g}}\,{\mathrm{cm}}^{-3}$ . The newly discovered exoplanets TOI-2373 b, TOI-2416 b, and TOI-2524 b have estimated equilibrium temperatures of ${860}_{-10}^{+10}$ K, ${1080}_{-10}^{+10}$ K, and ${1100}_{-20}^{+20}$ K, respectively, placing them in the sparsely populated transition zone between hot and warm Jupiters

Three long period transiting giant planets from TESS

We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single transit events in the light curves generated from the full frame images of the Transiting Exoplanet Survey Satellite (TESS). Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of $M_P$= 0.30 $\pm$ 0.04 $M_J$ , a radius of $R_P$= 1.00 $\pm$ 0.02 $R_J$ , and a low eccentricity orbit (e=0.15 $\pm$ 0.05) with a period of P= 30.08364 $\pm$ 0.00005 d . TOI 2338b has a mass of $M_P$= 5.98 $\pm$ 0.20 $M_J$ , a radius of $R_P$= 1.00 $\pm$ 0.01 $R_J$ , and a highly eccentric orbit (e= 0.676 $\pm$ 0.002 ) with a period of P= 22.65398 $\pm$ 0.00002 d . Finally, TOI 2589b has a mass of $M_P$= 3.50 $\pm$ 0.10 $M_J$ , a radius of $R_P$= 1.08 $\pm$ 0.03 $R_J$ , and an eccentric orbit (e = 0.522 $\pm$ 0.006 ) with a period of P= 61.6277 $\pm$ 0.0002 d . TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.Comment: 24 pages, 16 figures, accepted in A

TOI-199 b: A well-characterized 100-day transiting warm giant planet with TTVs seen from Antarctica

We present the spectroscopic confirmation and precise mass measurement of the warm giant planet TOI-199 b. This planet was first identified in TESS photometry and confirmed using ground-based photometry from ASTEP in Antarctica including a full 6.5$\,$h long transit, PEST, Hazelwood, and LCO; space photometry from NEOSSat; and radial velocities (RVs) from FEROS, HARPS, CORALIE, and CHIRON. Orbiting a late G-type star, TOI-199\,b has a $\mathrm{104.854_{-0.002}^{+0.001} \, d}$ period, a mass of $\mathrm{0.17\pm0.02 \, M_J}$, and a radius of $\mathrm{0.810\pm0.005 \, R_J}$. It is the first warm exo-Saturn with a precisely determined mass and radius. The TESS and ASTEP transits show strong transit timing variations, pointing to the existence of a second planet in the system. The joint analysis of the RVs and TTVs provides a unique solution for the non-transiting companion TOI-199 c, which has a period of $\mathrm{273.69_{-0.22}^{+0.26} \, d}$ and an estimated mass of $\mathrm{0.28_{-0.01}^{+0.02} \, M_J}$. This period places it within the conservative Habitable Zone.Comment: 33 pages, 23 figures. Accepted for publication in A

A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS

We report on the confirmation and follow-up characterization of two long-period transiting substellar companions on low-eccentricity orbits around TIC 4672985 and TOI-2529, whose transit events were detected by the TESS space mission. Ground-based photometric and spectroscopic follow up from different facilities, confirmed the substellar nature of TIC 4672985 b, a massive gas giant, in the transition between the super-Jupiters and brown-dwarfs mass regime. From the joint analysis we derived the following orbital parameters: P = 69.0480+0.0004−0.0005 d, Mp = 12.74+1.01−1.01 MJ, Rp =1.026+0.065−0.067 RJ and e = 0.018+0.004−0.004 . In addition, the RV time series revealed a significant trend at the ∼ 350 m s−1 yr−1level, which is indicative of the presence of a massive outer companion in the system. TIC 4672985 b is a unique example of a transiting substellar companion with a mass above the deuterium-burning limit, located beyond 0.1 AU and in a nearly circular orbit. These planetary properties are difficult to reproduce from canonical planet formation and evolution models. For TOI-2529 b, we obtained the following orbital parameters: P = 64.5949+0.0003−0.0003 d, Mp =2.340+0.197−0.195 MJ, Rp = 1.030+0.050−0.050 RJ and e = 0.021+0.024−0.015 , making this object a new example of a growing population of transiting warm giant planets

TCS and peripheral robotization and upgrade on the ESO 1-meter telescope at La Silla Observatory

In this work we describe the robotization and upgrade of the ESO 1m telescope located at La Silla Observatory. The ESO 1m telescope was the rst telescope installed in La Silla, in 1966. It now hosts as a main instrument the FIber Dual EchellE Optical Spectrograph (FIDEOS), a high resolution spectrograph designed for precise Radial Velocity (RV) measurements on bright stars. In order to meet this project's requirements, the Telescope Control System (TCS) and some of its mechanical peripherals needed to be upgraded. The TCS was also upgraded into a modern and robust software running on a group of single board computers interacting together as a network with the CoolObs TCS developed by ObsTech. One of the particularities of the CoolObs TCS is that it allows to fuse the input signals of 2 encoders per axis in order to achieve high precision and resolution of the tracking with moderate cost encoders. One encoder is installed on axis at the telescope and the other on axis at the motor. The TCS was also integrated with the FIDEOS instrument system so that all the system can be controlled through the same remote user interface. Our modern TCS unit allows the user to run observations remotely through a secured internet web interface, minimizing the need of an on-site observer and opening a new age in robotic astronomy for the ESO 1m telescope

Precise radial velocities of giant stars

Context. More than 100 exoplanets have been discovered around K and G giant stars, and their properties differ considerably from those of the planets found orbiting Sun-like and late-type main-sequence stars. This allows us to study the properties of planetary systems after the host star has evolved off the main-sequence, and it helps us to constrain planetary formation and evolution models. Aims. Our aim is to find out whether the long-period radial velocity variations observed in four giant stars of the Lick survey are caused by orbiting planets, and to study the properties of the planet population as a function of the stellar evolutionary stage. Methods. We analyzed 12 yr of precise radial velocity data for four stars of the Lick sample. In addition, we compared the planet frequency as a function of the evolutionary stage for two surveys, Lick and Express, based on the evolutionary stages derived using Bayesian inference. Results. We report the discovery of two new exoplanets and three exoplanet candidates orbiting giant stars. The best Keplerian fits to the data yield minimum masses of 2.5 MJ and 4.3 MJ for the planets orbiting HD 25723 and 17 Sco, respectively. The minimum masses of an additional candidate around HD 25723, and of planet candidates around 3 Cnc and 44 UMa, would be 1.3 MJ, 20.7 MJ, and 12.1 MJ, respectively. In addition, we compute planet frequencies for the Lick and Express samples as a function of the evolutionary stage. Within each sample, the planet frequency for the horizontal branch stars is the same as for the red giant branch stars. Conclusions. We have discovered two new exoplanets and three new exoplanet candidates, one of them being the second planet in a possible multi-planetary system. Based on our derived planet frequencies, we conclude that stellar evolution does not affect the number of observable planets between the red-giant and horizontal-branch evolutionary stages