Current calls
JAE-Intro IAA 2025 training plan on offer
The JWST telescope reveals that storms generated by forming stars create large cavities in their marental cloud
Supervisor: Mayra Osorio (osorio[at]iaa.es)
Group: Formación estelar, planetaria y evolución (https://spfe.es/en/people/mayra-osorio/)
When a star is born, it is surrounded by a cloud of gas and dust from which it feeds via an accretion flow that travels from the cloud to the star, passing through a flattened structure known as an accretion disk. However, accretion also drives the ejection of material, expelled by both the star and the disk, which escapes through cavities in the cloud carved out by these violent outflows. The James Webb Space Telescope (JWST) is now capturing unprecedented images of these cavities, as well as of winds and collimated matter ejections in the infrared (see figure).
By modeling these cavities with radiative transfer codes that reproduce the scattered starlight (red emission in the figure) within them, it is possible to infer the physical conditions in these regions and gain a deeper understanding of the star and planet formation process.
We propose the following tasks for student training:
- Adapt existing radiative transfer models to reproduce the scattered light within these cavities.
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The student will develop a model catalog to generate scattered light images within the cavities as a function of their density, temperature, and system geometry.
To achieve this, the student will use public codes such as RADMC3D, which generate synthetic images to be compared with those obtained through the HEFE program (to which M. Osorio belongs). This is the only star formation program awarded ~200 hours of JWST observation time to image 300 protostars in the Orion star-forming region. The study of these cavities will also be complemented with radio maps observed using the powerful interferometer ALMA.
The student will gain experience in programming and in interpreting mid- and near-infrared images of protostars observed with JWST, as well as in processing radio maps from ALMA. The Star and Planet Formation Group at the IAA-CSIC (https://spfe.es), which will host the student, includes experienced radio astronomers and modelers.
Pictured on the left is an image of two protostars (marked by a red star), showing their hourglass-shaped cavities and collimated outflows of material observed by the JWST.
Credits: Federman et al. 2024, ApJ, 966, 4.
Former calls
Orión, un excelente laboratorio para estudiar la formación de los planetas en condiciones diversas
Director: Mayra Osorio (osorio[at]iaa.es)
Grupo: Formación estelar, planetaria y evolución (https://spfe.es/en/people/mayra-osorio/)
Orión es la región de formación estelar más cercana (420 pc) donde conviven protoestrellas de distinta luminosidad, masa, y en diferentes ambientes. Todas se encuentran a la misma distancia lo cual facilita su estudio y comparación entre ellas.
El proceso de formación de una estrella, va acompañado de fenómenos de acreción de materia, mediante un disco de gas y polvo, que va hacia la protoestrella y eyección mediante flujos moleculares y jets que reducen el momento angular y permite que la estrella siga ganando masa. Se sabe que esta acreción/eyección puede ser episódica, puesto que cada vez que el disco acumula material lo pasa a la protoestrella de forma violenta, causando un aumento en la luminosidad. Dichas erupciones pueden registrarse gracias a las observaciones de archivo realizadas desde hace ~20 años. En Orión se han detectado que algunas protoestrellas varían en el infrarrojo en radio. Ello nos motiva a buscar más casos donde haya indicios de variabilidad. Por otro lado, en las fases finales de la evolución protoestelar, el disco se disipa y el polvo crece hasta alcanzar varios milimétricos, llegando a ser planetésimos y finalmente planetas. Tanto la variabilidad de la protoestrella como la disipación de su disco, son dos aspectos que necesitan ser explorados.
En nuestro grupo (https://spfe.es/) tenemos observaciones centimétricas con el interferómetro Very Large Array (VLA) de Orión, que nos ayudará a comprender estos fenómenos, así como también observaciones del gran interferómetro Atacama Large Millimeter Array (ALMA) que revelan los discos, y dispondremos de datos con el James Webb Space Telescope (JWST) que revelarán luz dispersada de las cavidades.
Proponemos como prácticas:
1. Reducir los datos del VLA de alguna región de Orión que el/la candidata/a escogerá y asociará con los discos observados con ALMA de nuestra base de datos (https://planetstarformation.iaa.es/).
Algunos discos presentan evidencia de fotoevaporación o crecimiento de granos. Así como también buscará la posible detección de jets cuya variación pueda ser corroborada en el futuro.
2. El candidato(a) actualizará nuestro catálogo online sobre Orión.
3. Para la región escogida el candidato(a) calculará la luz dispersada en las cavidades y la comparará con datos del JWST usando modelos que el grupo ha desarrollado.
Predoctoral Research Training Contract FPI (PREP2023-001438)
https://sitios.csic.es/web/sede/convocatorias/-/convocatoria/38031
This contract is part of the grants for the training of predoctoral research staff associated with the early processing call for the year 2023 within the “Knowledge Generation Projects” funding scheme, under the State Plan for Scientific, Technical, and Innovation Research 2021-2023 of the Spanish State Research Agency.
Thesis Title: Disks and Jets Throughout Stellar Evolution
Supervisors: Mayra Osorio, Guillem Anglada (osorio[at]iaa.es, guillem[at]iaa.es)
Research Group: Stellar and Planetary Formation and Evolution
The formation of a planetary system is likely accompanied by the photoevaporation of gas from the protoplanetary disk, along with planetary interactions, migrations, and subsequent collisions of bodies of different sizes. These processes ultimately lead to the production of a second generation of dust grains, forming what is known as a “debris disk” associated with the planetary system.
The main objective of this PhD project is to study the characteristics of debris disks around mature stars, which will help us gain a more comprehensive understanding of the configuration of their exoplanetary systems and trace their evolutionary history. To achieve this, we will primarily use observational data in the cm, mm, and submm wavelength ranges obtained with radio interferometers such as ALMA and VLA. Additionally, as a complementary study, we aim to analyze scattered light emission from these disks using JWST data.
The doctoral thesis will be supervised by Dr. Mayra C. Osorio Gutiérrez, an expert in dust disk modeling, and Dr. Guillem Josep Anglada Pons, an expert in radio astronomical observations, since the main scientific goal of the project is to study the properties and evolution of protoplanetary and debris disks.
The research group on stellar and planetary formation and evolution at the IAA is led by Dr. Guillem Anglada and includes Dr. Mayra Osorio, Dr. José F. Gómez, Dr. Luis F. Miranda, and Dr. Gary Fuller (external collaborator), as well as two postdoctoral researchers and several PhD and master’s students. Our group studies multiple aspects of the process of stellar and planetary formation, as well as the late stages of stellar evolution. We have expertise in both high-angular-resolution radio observations and theoretical modeling. We collaborate with numerous international researchers and participate in several international consortia.
Data reduction for single-dish and interferometric observations in radio wavelengths (centimeter, millimeter, and submillimeter).
Use of radiative transfer codes developed by the group to infer physical parameters from thermal emission (continuum and spectral lines) and scattered light.
Design and preparation of observation proposals for ALMA, VLA, and JWST, as well as writing scientific articles.
Attendance at seminars, schools, advanced courses, and international scientific conferences, as well as participation in outreach activities aimed at engaging the general public as part of the predoctoral training process.
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
Online Catalog of Models for Envelopes and Disks Around Evolved AGB-Type Stars
Supervisor: Mayra Osorio (osorio[at]iaa.es)
Group: Stellar and Planetary Formation and Evolution (https://spfe.es/people/mayra-osorio/)
One of the most intriguing topics in recent years has been the discovery of exoplanets around evolved stars (older than the Sun), raising the question of whether a second generation of planets has formed or if they have survived the violent end that a star undergoes in its final evolutionary stages. To investigate the presence of planets around these stars, we have developed radiative transfer models for the thermal dust emission from their circumstellar material, which may correspond to either an expanding envelope or an accretion disk. These models aim to answer a key question: Is the mass of the circumstellar material sufficient to form a second generation of planets? We have generated thousands of models of disks and envelopes for an online catalog, with the goal of making them available to the research community. These models are particularly relevant because most models of these stars found in the literature are rather simplistic, typically assuming constant temperature and density. Our models are an adaptation of radiative transfer codes originally developed for young stars, now adjusted to the physical conditions present in the environments of highly evolved stars. The selected candidate will work on improving the online catalog to provide users with spectral energy distributions (SEDs, see figures) that can be easily compared with observational data. The models have been generated by varying stellar luminosity, the mass of the circumstellar material, and the inclination and geometry of the system. In addition to the synthetic spectra, the catalog will also include the temperature and density distributions of the envelopes and disks. The candidate will gain experience in radiative transfer modeling, understand how the spectrum changes with variations in the aforementioned parameters, and test the database with a case study for which we have observational data from the near-infrared to the millimeter range. Furthermore, the candidate will contribute to the publication presenting the online model catalog to the scientific community. The images illustrate the database design and the synthetic spectra (envelope and disk) that have already been computed.
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
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.
