Research :: PhD Topics for 2016 :: Planets

Topics under the thematic lineTowards the detection and characterization of other Earths” available for the 2016 Call (11 PhD Topics):

  • 2016/115 - Search and characterization of transiting warm-jupiter planets detected by GAIA
  • 2016/116 – Cheops observations of transiting planets: measuring other worlds with a new eye
  • 2016/117 - Detecting the atmospheres of exoplanets with CHEOPS: combining theory and observations
  • 2016/118 - Detecting light from other worlds: the high-resolution spectroscopy approach
  • 2016/119 - Dissecting the atmospheres of low-mass stars: Precise stellar characterization with high-res NIR spectroscopy
  • 2016/120 - Detection and characterization of planets orbiting oscillating red-giant stars with NASA’s TESS mission
  • 2016/121 - Orbital evolution of planetary systems: from formation to today
  • 2016/122 - Planetary atmospheres – From Solar System to Exoplanets: atmospheric characterization and search for chemical disequilibrium compounds
  • 2016/123 - The awakening of the ESPRESSO planet-hunter: finding a twin of Earth
  • 2016/124 - Planetary atmospheric characterization using ALMA capabilities
  • 2016/125 – Seismic Probes for Giant Planets in the Solar System

For further details, please see the listing below, with abstracts and advisors. Prospective candidates are welcome to contact directly the proposers of the topics for inquiries and further details.

2016/115 - Search and characterization of transiting warm-jupiter planets detected by GAIA

AdvisersNuno C. Santos (IA U.Porto & DFA/FCUP), Marco Montalto (IA U.Porto)

The detection of transiting warm-jupiter planets (giant planets with orbital periods in between tens to hundred days) has been so far a challenging task due the small transit probability of these objects. This situation is going to change in the next future. In particular the GAIA space mission will soon deliver accurate astrometric measurements which will permit the astrometric detection of thousands of exoplanets most of which will be giant planets in intermediate period orbits characteristic of warm jupiters. Of the order of tens of these planets are expected to transit their host star offering invaluable opportunities for follow-up analysis and characterization. Astrometry permits in particular the unique possibility to calculate the inclination of a planetary system (beyond the other orbital parameters), and therefore allows us to predict if a given planet will transit its host star or not.

The search and characterization of transiting warm jupiters is going to be one of the most important research topics in the upcoming years in the field of exoplanets. Detailed studies of a new class of objects so far observationally inaccessible will be possible for the first time.

In this project the student will be required to: 1) identify warm jupiter planetary systems which offer the best opportunity for transit detection and characterization. This will be done primarily by coupling the newly delivered GAIA measurements with accurate radial velocities already available for hundreds of bright planet-host stars. By doing that, a precise estimate of the orbital inclination and of the transit detection probability will be obtained; 2) produce a ranked list of candidate transiting planets and a table of predicted transit ephemerides; 3) promote follow-up analysis to detect the transit; 4) Publish the results in international peer-reviewed journals.

Our group is in particular involved in the CHEOPS space mission, a space based satellite that will be launched next year and will be devoted to the discovery and characterization of transiting planets in particular around bright stars. Future follow-up analysis with CHEOPS of the best warm-jupiter candidate transiting planets detected by GAIA has been already granted to our team.

This project offers a great opportunity to develop a carrer in the field of exoplanets, and to estabilish collaborations with leading experts both in Portugal and abroad. Partecipation to future space missions in which our group is involved (like CHEOPS and PLATO) is also foreseen.

University: Porto

2016/116 - Cheops observations of transiting planets: measuring other worlds with a new eye

Advisers: Susana Barros (IA U.Porto), Nuno C. Santos (IA U.Porto & DFA/FCUP)

Many ongoing and future transit surveys for extrasolar planets (Kepler, K2, Tess and Plato) are delivering light curves with unprecedented precision. Our team is now particularly involved in the Cheops ESA mission, to be launched in the end of 2017. 
Cheops (CHarecterising ExOplanets Satellite) is a new ESA mission that will allow to observe key 
bright targets with specific characteristics.

The development of Cheops is also intimately related to our 
strong participation in the ESPRESSO (ESO) project, a new high
resolution spectrograph for the VLT telescopes. ESPRESSO will
allow to derive radial velocity measurements with an unprecedented precision, and hence it will permit to measure masses for the smallest known exoplanets.

Together, Cheops and ESPRESSO will give us a unique opportunity to
characterize the properties (mass, radius, composition, structure, shape)
of exoplanets.

The present project proposes to explore from a new light this unique data, coming from CHEOPS and ESPRESSO. In particular, we propose to develop a state of the art Bayesian transit and radial velocity fitting code. Besides the standard transit and radial velocity model this code should model rings, planetary occultations, Rossiter-McLaughlin effect, and tidal effects. Rings have never been detected around extra-solar
planets, but their signature should be present in both the transit
light curve and radial-velocity (through Rossiter-McLaughlin effect). 
The tidal star-planet interactions deform the planets, producing also significant deformation in the light curve (never detected, but expected
for some planets).
Hence, the code will allow to search for the signature of rings, planetary occultations, and tidal effects. All these effects that have been predicted by theory will be observable with the new instruments and will lead to better characterization the planetary systems.

Our team as privileged access to Cheops data hence the student access to this unique dataset. Furthermore, the tools developed during this project we may also use for other datasets: NASA K2, TESS missions and in the future for ESA PLATO mission. The results of this project will increase the scientific exploitation of these state of the art missions and lead to a better understanding of planetary systems.

University: Porto

2016/117 - Detecting the atmospheres of exoplanets with CHEOPS: combining theory and observations

AdvisersNuno C. Santos (IA U.Porto & DFA/FCUP), António García Muñoz (TU Berlin, Germany)

With the number of exoplanets increasing at a fast pace, the attention of exoplanetology is progressively focusing in their detailed characterization. This characterization effort will receive a major boost in the coming years, as a number of new telescopes both in space and on the ground become operative. To fully exploit the potential of the data to arrive, it is critical that similar efforts are spent on the development of theoretical tools that will enable the interpretation of observations.

The present project proposes a combined theoretical and observational approach to use data from new instruments to study the atmospheres of exoplanets. In particular, we will focus on the use of CHEOPS high precision photometry to detect and analyse the occultation signals for a variety of planets orbiting stars with different properties. A statistical analysis of the data, coupled with the model predictions, will allow to understand new physical processes in the atmospheres of exo- worlds.

University: Porto

Notes: The student will spend up to one year in Berlin.

2016/118 - Detecting light from other worlds: the high-resolution spectroscopy approach

AdvisersNuno C. Santos (IA U.Porto & DFA/FCUP), Pedro Figueira (IA U.Porto)

With the number of exoplanets increasing at a fast pace, the attention of exoplanetology is slowly focusing in their detailed characterization. The detection of exoplanet atmospheres is now a reality for at least the most favourable cases, though in general not in great detail. In the present project we propose to develop a methodology to detect the spectra of exoplanets using high- resolution spectroscopy, and in particular to study the reflectance of the exoplanet as a function of wavelength. The methods will be used with the new ESPRESSO (ESO) instrument that will soon start operating at the VLT. Together with planet atmosphere models, the observations will allow us to probe and understand in unique detail the physical and chemical conditions of the observed planets.

University: Porto

2016/219 - Dissecting the atmospheres of low-mass stars: Precise stellar characterization with high- res NIR spectroscopy

Advisors: Sérgio Sousa (IA U.Porto), Elisa Delgado-Mena (IA U.Porto), Barbara Rojas-Ayala (IA U.Porto)

This project will be focused on the spectroscopic analysis of near-infra-red (NIR) spectra of M-dwarf stars with the goal of deriving precise and homogeneous stellar parameters. Although these cool M stars are the most common stars in our Galaxy they still represent an outstanding challenge in what regards their characterization.

The knowledge of the stellar parameters of planet-hosts, in particular their radii, is essential for the derivation of the properties of the discovered planets. The goals of the present project will have important impact in the scientific community and are of great importance for the full success of future space missions like TESS, CHEOPS, and PLATO.

With this in mind, the goal of the proposed project is to use current methodologies for the spectroscopic analysis of near-IR high resolution spectra that will soon be available from new instruments such as SpiRou, CARMENES, and CRIRES+. Moreover, we intend to develop a method based on spectral synthesis that could be used as an alternative for this kind of stars. These methods will be applied to M stars hosting planets. Besides the determination of precise stellar (and thus planetary) properties, the student will then further explore possible correlations between the properties of the stars and the presence of the planets, which can give important clues for planet formation models.

University: Porto

Notes: This topic is also offered as topic 2016/217, under the thematic line on Stars.

2016/120 - Detection and characterization of planets orbiting oscillating red-giant stars with NASA’s TESS mission

Advisors: Tiago Campante (University of Birmingham, UK),  Margarida Cunha (IA U.Porto), Nuno Santos (FCUP & IA U.Porto)

The Transiting Exoplanet Survey Satellite (TESS) is a NASA space mission with scheduled launch for late 2017 that will perform a wide-field survey for planets transiting bright nearby stars. Furthermore, TESS’s excellent photometric precision, combined with its fine time sampling and long intervals of uninterrupted observations, will enable asteroseismology (i.e., the study of stars by the observation of their natural oscillations) of solar-type and red-giant stars. Asteroseismology is proving to be particularly significant for the study of red-giant stars while quickly maturing into a powerful tool whose impact is being felt more widely across different domains of astrophysics. A noticeable example is the synergy between asteroseismology and exoplanetary science. TESS hence offers the exciting prospect of conducting asteroseismology on a significant number of evolved exoplanet-host stars. The main goal of this project will be to use TESS photometry to systematically detect and characterize transiting planets orbiting oscillating red-giant stars. To that end, we propose an end-to-end PhD project that will provide the student with skills in (i) transit photometry analysis, (ii) asteroseismic data analysis and stellar modeling, and (iii) radial-velocity/spectroscopic techniques. The implications of this project are far-reaching. The proposed systematic search for transiting planets orbiting oscillating red-giant stars is expected to provide new insights into some of the outstanding problems in exoplanetary science, namely, (i) on the planet occurrence rate as a function of stellar mass/evolutionary state, (ii) on the correlation between stellar metallicity and planet occurrence around evolved stars or (iii) on the structural aspects of gas-giant planets.

University: Porto

Notes: This topic is for a mixed fellowship (up to 12 months  in Birmingham). This topic is also offered as topic 2016/118, under the thematic line on Stars.

2016/121 – Orbital evolution of planetary systems: from formation to today

Advisors: Alexandre Correia (Univ. Aveiro), Vardan Adibekyan (IA U.Porto), Pedro Figueira (IA U.Porto)

The field of extrasolar planets research is tee­ming with activity. Last year we celebrated the 20th anniversary of the discovery of the first planet outside our system, and yet we count already over 2000 confirmed planets and hundreds of candidates to confirm. With a fast­growing discovery pace and a bright future ahead guaranteed by large number of ongoing and planned projects, it presents itself as the emerging astronomy topic of the new century.

As the planetary zoology continue, recent studies have shown that stellar properties (like, mass, evolutionary stage, and metallicity) also play a very important role not only on the formation of planets, but also on the orbital evolution. Several remarkable observational results can be outlined from these studies, that are still waiting for a solid explanation: planets in the metal­poor systems form/evolve differently appear to form farther out from their central star and/or they form later and do not migrate far; low­metallicity stars have a deficit of eccentric planets between 0.1 and 1 AU when compared to their metal­rich counterparts, because of either a less effective planet­planet interactions or due to the self­shadowing of the disk by a rim located at the dust sublimation radius (approx. 0.1 AU).

Planet­planet and planet­disk gravitational interactions during the formation process emerge as important orbit­shaping to be explored for a better understanding of the evolution of planetary systems. With this application we propose to study the impact of stellar metallicity on the orbital evolution of planetary systems from the observational point of view and to develop new simulations in which we consider the effect of disk and/or a companion planet’s presence on the planetary parameters. A linkage between theory and observations as presented here is uncommon, but crucial to understand our picture of extrasolar system. The different expertise of the supervisors will allow for a more encompassing work than before.

University: Porto

2016/122 - Planetary atmospheres – From Solar System to Exoplanets: atmospheric characterization and search for chemical disequilibrium compounds

Advisors: Pedro Machado (IA U.Lisboa), Pedro Figueira (IA U.Porto)

High-resolution visible and infrared (in the CO2 transparency windows) spectroscopic capabilities to the Solar System planets opens a new window by accessing atmospheric composition, mixing ratios and isotopic ratios, in particular, the measurement of the spectral lines’ Doppler shifts allows the retrieval of wind velocities and thus contribute to constrain planetary circulation dynamics.

Solar System observations and data reduction techniques, besides their own relevance research sake, serve as a stepping-stone for the study of extrasolar planets. In this project we propose to use them as a starting point for the development and test of atmospheric characterization tools. In a second phase the fine-tuned protocols will be adapted and applied to exoplanetary targets in order to constrain their atmospheric composition. The research will be focused in the presence of chemical disequilibrium compounds.

University: Lisboa/Porto

2016/123 - The awakening of the ESPRESSO planet-hunter: finding a twin of Earth

Advisors: Pedro Figueira (IA U.Porto), Nuno Santos (IA U.Porto & DFA/FCUP)

In 2018 the most anticipated planet-hunter machine will go online. From Paranal Observatory, the ESPRESSO spectrograph will be able to record with unprecedented precision the radial velocity of nearby stars. Its declared goal is clear: to find an Earth-mass planet inside the habitable zone around a star similar to our very own. The Institute of Astrophysics and Space Sciences (IA) has been behind the development of ESPRESSO since its inception, participating in the design and construction, and maximizing the scientific output of the spectrograph. As we enter this very last stage of the project, we have to put together the information we gathered on which stars are we more likely to detect earth-like planets, and define the final ESPRESSO catalog. The student will make use of data from two recently awarded ESO proposal datasets, on HARPS and UVES spectrographs, to pave the way to ESPRESSO and assist on the very first observations of the instrument. This will be done, specifically by studying the stellar granulation and activity signatures of our own star, the Sun, and by using high-resolution spectra to investigate the key stellar characteristics of the main planet-host candidates.

University: Porto

2016/124 - Planetary atmospheric characterization using ALMA capabilities

Advisors: Pedro Machado (IA U.Lisboa), Hugo Messias (IA U.Lisboa)

The advent of the Atacama Large (sub-)Millimeter Array (ALMA) brought new research perspectives to the planetary systems atmospheres scientific community. The facility’s spectral and spatial resolution powers, together with its detection speed, gives the community an opportunity for many new discoveries.

The focus targets of the project are four Solar-system objects, three of which (Mars, Uranus, and Titan) are frequently observed by ALMA for calibration purposes, gearing this project with a very rich, continuously growing, (sub-)mm integral spectroscopy data-set.

The main goals of the project are to assess the atmosphere dynamics and photochemistry as well as the search for minor species in Venus, Mars, Uranus, and Titan. More specifically: CO mapping and dynamics in all the targets; mesospheric winds in Venus and Mars; HDO, Chlorine and Sulphur species in Venus; HDO and H2O2 in Mars; and HCN mapping in Uranus and Titan.

The data necessary to fulfil these goals are already accessible via the ALMA archive. Nevertheless, dedicated ALMA observing proposals will be pursued when in need for longer integration, specific spectral tuning or array configuration.

University: Lisboa

2016/125 - Seismic Probes for Giant Planets in the Solar System

Advisors: Mário J. P. F. G. Monteiro (IA U.Porto & DFA/FCUP), Pedro Machado (IA U.Lisboa)

The calculation of interior models for planets is still strongly dependent on several unknowns. Namely the equation of state in the regimes expected to exist in the interior of those planets (including for solids, melting metals, liquids and gas) and the unknown interior chemical composition and stratification in those planets. Therefore, new tools to validate planetary models are required. These may be used to study the planets in the solar system, but space missions in preparation hold the promise of extending those studies to planets in other stars.

The proposed project has a theoretical component, involving a major effort on developing numerical codes. These are needed to provide a theoretical overview on how the equations of state and chemical stratification give global seismic indices able to identify the key components of the interior structure of planets. These models and the seismic tools will be used to predict how future observations should be planned and to establish what new physics may be required to fit the data we expect to collect. The work will focus on using the basic structure and evolution equations to model different planet interior configurations with the quality required to perform global seismic studies of those models. The student will develop numerical codes to implement the structure equations and the physics adequate for specific populations of planets. This will be done in order to obtain a structure that is precise and adequately described for obtaining the seismic properties of the models. After this goal is achieved, specific seismic indices for studying different planets and interior configurations will be explored in order to build a reference set of tools that can be used for probing some of the giant planets in the solar system.

The project also includes an observational component, which will consist in applying high- resolution spectroscopic capabilities to the gaseous giant planets of the Solar System. These observations and related data reduction techniques, will be applied to the adaptation of the Doppler velocimetry protocols previously developed to measure wind velocities in the framework of atmospheric dynamical studies upon Venus and, more recently, upon Saturn, to perform asteroseismology studies. These atmospheric characterization tools rely on high resolution spectroscopy techniques applied to spectra with high spectral resolution (R~100000), these protocols will be adapted and applied in order to probe and retrieve seismic waves and their propagation in these targets. The research will focus in the detection of seismic activity in the gaseous giant planets in order to constrain their main characteristics.

University: Porto