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INPhINIT PhD Fellowship: Establishing the stages of planet formation

Institution: Instituto de Astrofísica de Andalucía (IAA-CSIC)
Type: Pre-doctorate
Country: Spain
Application start date: Wed, 01/11/2023
Application end date: Wed, 24 January 2024, at 2 pm Peninsular Spain

The doctoral fellowship programme INPhINIT ”la Caixa” is devoted to attracting talented Early-Stage Researchers of any nationality to pursue their PhD studies in the best Spanish and Portuguese research centres and units with excellence distinction.

During their formation, stars are surrounded by disks of gas and dust that progressively evolve to create planetary systems. With the advent of a new generation of astronomical facilities, such as the Atacama Large Millimeter/submillimeter Array (ALMA) or the Karl G. Jansky Very Large Array (VLA) radio interferometers, we have been able to obtain increasingly sharper images of these protoplanetary disks. Disks with asymmetries, central cavities, gaps, bright rings, and spirals, thought to be produced by forming planets, are frequently found. This indicates that planetary formation is consubstantial with the star formation process.
The proposed PhD project will be devoted to explore several crucial phases of the planet formation process, through the observation and modelling of the dust and gas emission in a selected sample of protoplanetary disks identified by our group around young stars in different evolutionary stages (Osorio et al. 2014, ApJ. 586, 1148; Macías et al. 2016, ApJ. 829, 1; Tobin et al. 2020, ApJ. 890,130; Añez-López et al. (2020), ApJ. 888, 41; Diaz-Rodriguez et al. 2022, ApJ 930, 91).

 

The thesis project will be supervised by Dr. Mayra Osorio and Dr. Guillem Anglada, who are experts in the field of planet and star formation, radio astronomy and radiative transfer models.
The research group of star and planet formation and evolution, at the IAA is led by Dr. Guillem Anglada, and also includes Dr. Mayra Osorio, Dr. José F. Gómez, Dr. Luis F. Miranda, and Dr. Gary Fuller (external collaborator), two postdocs and several PhD and master students. Our group studies multiple aspects of the star and planetary formation process, as well as the late phases of stellar evolution. We have expertise both in radio observations at very high angular resolution and in theoretical modelling. We have numerous international collaborators, and we are involved in various international consortia.

Recently, signs of planetary formation, such as annular and spiral structures, have been reported in disks around very young (class 0) protostars (Segura-Cox et al. 2020, Nature, 586, 228; Cheng et al. 2022, ApJ. 933, 178), indicating that planets start to form at the very early stages of star formation. To properly understand the whole process of planetary formation, it is necessary to study all the evolutionary sequence, from the first disk assembling to the final dispersion of its gas content. So far, these two extremes of the protoplanetary disk evolution have not been explored in detail, but using high-quality data of both the ALMA and VLA interferometers we are in a very good position to better understand them. To do so, it will be necessary to determine the physical and chemical conditions of the disk in each phase, by means of state-of-the-art radiative transfer models.
The candidate will achieve the goals of the PhD thesis through both observations (new proposals and exploitation of archives of telescopes such as VLA or ALMA) and modelling (using codes developed by our group or by close collaborators). Such a PhD profile, with both modelling and radio observational skills, is highly demanded and necessary for a successful exploitation of new (upgraded VLA, ALMA) and future radio astronomical facilities (SKA, ngVLA). These facilities provide increasingly sophisticated images and results that require of both observational and theoretical expertise for their analysis and physical interpretation. The PhD researcher is expected to spend short stays at renowned research centers, such as ALMA-ESO (Chile and Germany), the ALMA node at University of Manchester (UK), or NRAO (USA). He/she will also attend specific training courses on radio interferometry (NRAO, SMA, or IRAM) and international conferences.

JAE-Intro IAA SO 2023 training plan on offer

Near Infrared Observations of Massive Protostellar Outlfows
Supervisor: Rubén Fedriani (fedriani[at]iaa.es)
Group: Star Planet Formation and Evolution (https://spfe.es/people/ruben-fedriani/)
Massive stars are significant in our understanding of astrophysics. They are primarily responsible for populating the universe with its rich chemical complexity, including us. They also produce a profound influence on their neighbouring environments, driving powerful tidal and radiation forces. However, the mechanisms by which massive stars form remain poorly understood. They are often shrouded in dense clouds of gas and dust while they form, posing difficulties in observing them in many wavelengths, including visible, due to the blocking of light by the cloud. However, at infrared wavelengths we can pierce through this veil of gas and dust and peer into the formation of protostars in orderto constrain their properties and test theories about their formation. A key physical phenomenon which can shed light on massive star formation is the outflow of protostellar jets, which is the natural consequence of an accretion disk that feeds the main protostar. These protostellar outflows eject considerable amounts of materials from the star+disk system. We propose to conduct a comprehensive analysis of a large dataset of near-infrared images of massive star forming regions that include extended emission of protostellar outflows. The data have been collected using world- class telescopes including the Hubble Space Telescope (HST) and the Large Binocular Telescope (LBT). The dataset comprises diffraction-limited images in the case of HST and images from the LBT. This project will be a complement to the ongoing SOFIA Massive (SOMA) Star Formation Survey. We propose to conduct a thorough analysis of protostellar outflows through imaging data. We will clean and process the available data set in order to discern the characteristics of the massive star forming regions, as well as kinematic and dynamic properties of the outflows. This project will motivate future James Webb Space Telescope proposals, since it can penetrate deeper into the massive star forming regions. See a more detailed description of this project at this url https://drive.google.com/file/d/10aFxrJjQmTIfwJ8Q2XATUlXAalKoQpse/view.

JAE-Intro CSIC 2023 training plans on offer

Protoplanetary disks around two or more young stars Supervisor: Mayra Osorio (osorio[at]iaa.es) Group: Star Planet Formation and Evolution (https://spfe.es/people/mayra-osorio/) Understanding how a star is born and how a planetary system like ours is formed is one of the most striking questions of modern astrophysics. The stellar embryo (the protostar) grows surrounded by a cloud of gas and dust that, due to its rotation, forms a disk around it, which feeds the star with material and is therefore called an accretion disk. This disk, in turn, evolves and may end up forming a planetary system. The excess material, which does not end up forming part of the star or the planetary system, is expelled to enormous distances by powerful jets. This scenario is known as the paradigm of star formation for a solar-type star. Today we wonder if this paradigm is valid for stars with a mass other than solar, or for binary stars that are born simultaneously from the same cloud fragment. These systems are different from the one that probably gave rise to our Solar System because they are composed of three disks, a disk around each of the protostars and a disk surrounding both, called circumbinary. It is observed that these disks, in some cases, do not have axial symmetry since they exhibit a spiral structure. To study the formation process of binary systems, we have developed a grid of accretion disk models (hundreds of models) to try to explain the observed dust emission (spectrum + image). We propose to organize these models and choose the best cases to reproduce the observations, especially the images obtained with the large radio interferometers (Atacama Large Millimeter Array and Very Large Array) of some emblematic systems that we have already identified. Simultaneously, we propose to calculate hydrodynamic models (using publicly available codes) that include deviations from axial symmetry to start simulating the spiral structure of circumbinary disks.

Mass loss phenomena in young and evolved stars
Supervisor: José Francisco Gómez Rivero (jfg[at]iaa.es)
Group: Star Planet Formation and Evolution (https://spfe.es/people/jose-francisco-gomez/)
Many different astrophysical scenarios share common elements, although at different scales. One of the most spectacular is the production of mass-loss phenomena, in many cases with extreme collimation (jets). These jets are present in objects such as active galaxy nuclei (on scales of several parsecs), microquasars, young stellar objects, or evolved stars (on scales of astronomical units). In these cases, the presence of an accretion disk is required for the release of collimated mass loss. In this work, we propose a study of mass loss phenomena in young and evolved stars, and their associated structures (accretion disks), using public databases from different radio telescopes.
Plan foreseen:
1- Several candidate sources, in star-forming regions or in evolved stars, will be proposed to the selected person.
2- Public data available in the archives of radio telescopes such as Very Large Array, Atacama Large Millimeter/submillimeter Array, or Australia Telescope Compact Array will be searched.
3- A critical analysis will be made of the accessible data and the scientific objectives achievable with them in the time available with this grant. At least one source will be selected for study.
4- The data will be downloaded and their calibration, quality evaluation and analysis will be performed.
5- A report of the results will be prepared, which may be the germ of a contribution to a conference or an article in a peer-reviewed journal.

Searching for faint radio sources in Orion
Supervisor: Teresa Gallego (gallego[at]iaa.es)
Group: Star Planet Formation and Evolution (https://spfe.es/people/aurelia-teresa-gallego-calvente/)
The birth of a star is accompanied by the accretion of matter through a disk and ejection in the direction perpendicular to the disk, which reduces the angular momentum and allows the star to continue gaining mass. We now know that this accretion and ejection of matter can be episodic, since each time the disk accumulates enough material from the parent cloud, it is passed to the protostar causing an increase in luminosity. On the other hand, in the final phases of protostellar evolution, the gas in the disk is photoevaporated and its dust grains can grow to millimeter sizes to eventually form planetesimals and, eventually, planets. Both the variability of the protostar and the dissipation of its circumstellar disk to become a planetary system are two little-known aspects that need to be explored. In our research group, we have observed several regions of Orion that will shed light on these phenomena, since Orion is a region very rich in protostars of different luminosities, evolutionary states and all placed at the same distance. We propose in this Jae-Intro internship to reduce the centimeter data that we have obtained with the Very Large Array radio interferometer in its most compact configuration, located in the United States. The candidate will choose the region whose data he/she wants to process and identify the disks already observed with ALMA from our online Orion database (https://planetstarformation.iaa.es/) photoevaporating or with possible grain growth and their jets.

INPhINIT PhD Fellowship: Exploring the diversity of planetary systems

Institution: Instituto de Astrofísica de Andalucía (IAA-CSIC)
Type: Pre-doctorate
Country: Spain
Application start date: Tue, 01/11/2022
Application end date: Wed, 25/01/2023

The doctoral fellowship programme INPhINIT ”la Caixa” is devoted to attracting talented Early-Stage Researchers of any nationality to pursue their PhD studies in the best Spanish and Portuguese research centres and units with excellence distinction.

Stars are formed surrounded by a disk of gas and dust that progressively evolves to form a planetary system. With the advent of a new generation of telescopes and astronomical facilities, such as the Atacama Large Millimeter/submillimeter Array (ALMA) radio interferometer, we have been able to obtain increasingly sharp images of these protoplanetary disks and discern fine details of the onset of the planet formation process. Disks with asymmetries, central cavities, gaps, bright rings, spirals, thought to be produced by forming planets, are frequently found. All this indicates that planetary formation is consubstantial with the star formation process, suggesting a large abundance of planets, comparable to the number of stars in the Universe. The continuous discoveries of new exoplanets confirm that they are very abundant in our Galaxy. One of the most surprising result has been the great diversity of exoplanets and architectures of the exoplanetary systems that are being found. This diversity should also be reflected in their progenitors, the protoplanetary disks. However, this diversity in the disks has not yet been well explored, neither from an observational nor a theoretical perspective. The PhD thesis will be devoted to explore this diversity in protoplanetary disks by studying a sample of emblematic cases, which we have already identified.

The research group, led by Dr. Guillem Anglada, is formed also by Dr. Mayra Osorio, Dr. José F. Gómez, Dr. Luis F. Miranda, 1 postdoc, and several PhD and master students. We study multiple aspects of the star and planetary formation process, as well as the late phases of stellar evolution. We have expertise both in radio observations at very high angular resolution and in theoretical modelling. We have numerous international collaborators, and are involved in various international consortia in UK, Chile, Mexico, USA, Germany, India, Australia, and France, among others.

The thesis project, supervised by Dr. Mayra Osorio and Dr. G. Anglada, will focus on the study of protoplanetary disks in various “peculiar” environments, in order to explore the extent of their diversity with the aim of understanding its connection with the observed diversity in exoplanets and in the architecture of exoplanetary systems. The physical conditions of a sample of disks around massive stars, disks in binary systems and extremely compact disks in very low luminosity M-type stars, will be studied, as they mark the initial conditions to build a planetary system.
The candidate will achieve this goal through both observations (new proposals and exploitation of archives of telescopes such as VLA or ALMA) and modelling (using codes developed by our group or close collaborators). Such a PhD profile, with both modelling and radio observational skills, is highly demanded and necessary for a successful exploitation of new (upgraded VLA, ALMA) and future radio astronomical facilities (SKA, ngVLA). These facilities provide increasingly sophisticated images and results that require of both observational and theoretical expertise for their analysis and physical interpretation.
The student is expected to spend short stays at renown research centres, such as ALMA-ESO (Chile and Germany), ALMA node at University of Manchester (UK), or NRAO (USA). He/she will also attend specific training courses on radio interferometry (NRAO, SMA, or IRAM) and international conferences.