Magnetic fields are primary drivers of stellar formation and have profound implications on stellar evolution (on the transport of chemical species and angular momentum), as well as on the formation of planetary systems around the hosting star.

Yet, stellar magnetic fields are often overlooked since they are elusive, difficult to detect, and challenging to model properly.

Spectropolarimetry is the only tool that allows us to obtain quantitative information on the strength and topology of the magnetic field. However, it has been little exploited since it is a photon starving technique and the data are difficult to interpret. This project aims at exploiting spectropolarimetric techniques to make some breakthrough contributions to the field of stellar magnetism, by characterising the magnetised outer atmospheres of cool stars and investigating the potential impact of magnetic fields on long-term stellar evolution.

Stellar chromospheres are a critical transition layer where the relatively cool photosphere gives way to the million-degree corona and to the stellar environment in which planets are embedded. Despite their importance, the magnetic mapping of stellar chromospheres has never been attempted. One of the main objectives of this project is to build a synthesis code of the radiative transfer of polarised light in cool stars photosphere and chromosphere for an empirical investigation of the magnetism of stellar chromospheres and its coupling to other atmospheric layers. This will help us solving one of the long lasting problems in stellar physics: the heating of the outer atmospheres, in which we know that magnetic fields play an important role. Prominences are cool chromospheric material magnetically levitating in the hot coronae of the Sun and of other stars harbouring similar magnetic activity. The magnetic field plays a fundamental role in the formation, support, and eruption of stellar prominences yet, the magnetism of these structures has not been reliably measured. This project has the challenge to measure the polarisation signals of stellar prominences and the study of the magnetic fields in these structures.

Stars similar to our Sun end their lives as a planetary nebulae (PNe) with a hot star in its centre. One would expect that a star loses its atmosphere isotropically, but about 80% PNe are bipolar or very asymmetric. The reason for this is not yet understood. The presence of magnetic fields would nicely explain these complicated shapes, as the ejected matter is trapped along the field lines. However, magnetic fields in PNe have been elusive and we have not clearly detected them. In this project, we aim the detection of magnetic fields in the central stars of PNe and proto-PNe. The light coming from most astrophysical sources is only weakly polarised and the polarisation signals are difficult to detect. This justifies to build a pectropolarimeter in 10m-class telescopes. The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is an instrument to be installed at the 10.4m Gran Telescopio Canarias in 2020, with the participation of the PI of this project in the scientific working group. MIRADAS will open a completely unexplored window into stellar magnetism, hence the aim of this project is to develop numerical techniques for the interpretation of the wealth of data that this instrument will offer attached to the largest telescope in the worl.

Magnetic fields are primary drivers of stellar formation and have profound implications on stellar evolution (on the transport of chemical species and angular momentum), as well as on the formation of planetary systems around the hosting star.

Yet, stellar magnetic fields are often overlooked since they are elusive, difficult to detect, and challenging to model properly.

Spectropolarimetry is the only tool that allows us to obtain quantitative information on the strength and topology of the magnetic field. However, it has been little exploited since it is a photon starving technique and the data are difficult to interpret. This project aims at exploiting spectropolarimetric techniques to make some breakthrough contributions to the field of stellar magnetism, by characterising the magnetised outer atmospheres of cool stars and investigating the potential impact of magnetic fields on long-term stellar evolution.

Stellar chromospheres are a critical transition layer where the relatively cool photosphere gives way to the million-degree corona and to the stellar environment in which planets are embedded. Despite their importance, the magnetic mapping of stellar chromospheres has never been attempted. One of the main objectives of this project is to build a synthesis code of the radiative transfer of polarised light in cool stars photosphere and chromosphere for an empirical investigation of the magnetism of stellar chromospheres and its coupling to other atmospheric layers. This will help us solving one of the long lasting problems in stellar physics: the heating of the outer atmospheres, in which we know that magnetic fields play an important role. Prominences are cool chromospheric material magnetically levitating in the hot coronae of the Sun and of other stars harbouring similar magnetic activity. The magnetic field plays a fundamental role in the formation, support, and eruption of stellar prominences yet, the magnetism of these structures has not been reliably measured. This project has the challenge to measure the polarisation signals of stellar prominences and the study of the magnetic fields in these structures.

Stars similar to our Sun end their lives as a planetary nebulae (PNe) with a hot star in its centre. One would expect that a star loses its atmosphere isotropically, but about 80% PNe are bipolar or very asymmetric. The reason for this is not yet understood. The presence of magnetic fields would nicely explain these complicated shapes, as the ejected matter is trapped along the field lines. However, magnetic fields in PNe have been elusive and we have not clearly detected them. In this project, we aim the detection of magnetic fields in the central stars of PNe and proto-PNe. The light coming from most astrophysical sources is only weakly polarised and the polarisation signals are difficult to detect. This justifies to build a pectropolarimeter in 10m-class telescopes. The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS) is an instrument to be installed at the 10.4m Gran Telescopio Canarias in 2020, with the participation of the PI of this project in the scientific working group. MIRADAS will open a completely unexplored window into stellar magnetism, hence the aim of this project is to develop numerical techniques for the interpretation of the wealth of data that this instrument will offer attached to the largest telescope in the worl.