At the beginning of 2026, from January 4 to February 3, I was hosted by prof. Lydia Cidale at the University of La Plata (UNLP), in the frame of the OCEANS project. The subject of our ongoing collaboration is the study of variability in B-type supergiant stars (BSGs) using public available data from large-scale photometric surveys and optical spectroscopy conducted and processed by the host group. With recently obtained observing time with the Jorge Sahade (JS) 2.15m telescope at the CASLEO observatory, we were co-planning our observations of BSGs that will be simultaneously monitored by the TESS telescope, during the period February-May 2026. The synergistic approach using ground and space-based data will help us to untangle the origin of the fine photometric variability, investigate possible connection between the stellar wind and pulsations, and to draw correlations with the parameters of these objects. Moreover, along with the PhD student M. Ruiz Diaz, time was also devoted on the analysis of multi-periodic signal and red noise of five BSGs as part of an ongoing study of their wind (Ruiz Diaz in prep.), whereas the contamination in the light curves of BSGs and the ways to addressing it using modern tools was explored along with the PhD student A. Alberici. With the latter student, we co-planned observations of binaries containing BSGs during the upcoming observing program for the purposes of modeling their orbital parameters, an objective of my next secondment trip to UNLP with OCEANS.

The period of Jan 17-22 was exceptionally intriguing, as I had the chance to attend the observing procedure led by M. Ruiz Diaz and L. Cidale, at the JS 2.15m telescope. Our trip to the province of San Juan and then, to the facilities of the CASLEO observatory at the altitude of ~2300 m, was a stimulating experience. The trip served the purposes of a BSG study of Ruiz DIaz, yet I had the chance to also obtain data of a transition-phase massive star and synchronously with the TESS satellite, as a foretaste of the upcoming program. Beyond this experience, the desolate landscape of the Argentinian mountains offered some memorable moments.

Thanks to OCEANS, distances are shortened and different cultures are met. The hot climate in the city of La Plata was challenging during January, yet it was nicely balanced by the smooth collaborative workflow.

During my stay in Valparaiso, I worked with Rodrigo Meneses at the Faculty of Engineering of the University of Valparaiso. Our main objective is obtaining precise values for the non-adiabatic pulsation modes of massive stars with highly non-adiabatic envelopes (log(L/M)>4). In order to accomplish this, we are studying the Riccati method using a shooting method independent of the adiabatic roots, which are known to be very different from the non-adiabatic ones in this case. We began deducing the perturbed equations for the radial and non-radial case assuming linear perturbations. We focused on radial pulsations. We wrote the pulsation equations as a function of the radius. We applied the Riccati method and obtained the Riccati equation as a function of this variable. This method requires the proper selection of an intermediate grid point to obtain the set of equations for the interior and external regions of the star. In order to select this value, we developed a MESA model of a massive star at the post-RSG stage with high log(L/M) and studied the asymptotic behaviour of the stellar structure coefficients involved in our set of equations, in function of the radius for this MESA model. Our next step is to discretize the problem.

Besides my work with Rodrigo, I had the chance to discuss my paper on the use of Intrinsic Mode Functions (IMF) to analyze the red noise in massive stars with Alejandra Christen at the Statistical Institute of the University of Valparaiso and I gave a seminar on this topic entitled “Filtering red noise in massive stars with IMF”. I also joined Alejandra and other professors at the “PhD Student Seminar 2025 “ devoted to the training of phD students in the presentation of their research projects.

Beyond work, I enjoyed Valparaiso’s traditional cuisine, the beach, and the breathtaking landscapes. I am deeply grateful to Rodrigo, Alejandra, Michel Cure and Catalina Arcos for their kindness, time, and the nice moments we shared. They made my stay meaningful, valuable for my work, and really enjoyable. I'm looking forward to visiting Valparaiso again!