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In this poster, we will summarise the review paper entitled: "Revisiting the archetypical wind accretor Vela X-1 in depth. Case study of a well-known X-ray binary and the limits of our knowledge." The paper, published in late 2021 in Astronomy and Astrophysics journal, triggered a discussion amongst the editors of Astronomy and Astrophysics leading to the creation of a new type of review article on uniquely interesting objects. In the paper we have: provided a thoughtful compilation of the knowledge of the Vela X-1 system and its modelling published over decades; added new information derived from public data or catalogues, including an updated distance and spectral classification based on the Gaia EDR3 release; and identified specific avenues of future research that could help to clarify open questions.

Trabajo presentado al 12th INTEGRAL Conference - 1st AHEAD Gamma-ray Workshop: 'INTEGRAL Looks AHEAD To Multi-Messenger Astrophysics', celebrados en Geneva (Switzerland) del 11 al 15 de febrero de 2019., Vela X-1 is an eclipsing high mass X-ray binary (HMXB) consisting of a 283s accreting X-ray pulsar in a close orbit of 8.964 days around the B0.5Ib supergiant HD77581 at a distance of just 2.4 kpc. The system is considered a prototype of wind-accreting HMXB and it has been used as a baseline in different theoretical or modelling studies. We discuss the observational properties of the system and the use of the observational data as laboratory to test recent developments in modelling the accretion process in High-Mass X-ray Binaries (e.g., Sander et al. 2018; El Mellah et al. 2018), which range from detailed descriptions of the wind acceleration to modelling of the structure of the flow of matter close to the neutron star and its variations.

Trabajo presentado al X-Ray Astronomy: 'Current challenges and New Frontiers in the Next Decade', celebrado en Bologna (Italia) del 8 al 13 de septiembre de 2019., The eclipsing high mass X-ray binary Vela X-1 consists of an accreting X-ray pulsar orbiting an early type supergiant with an orbital period of ~ 9 days. It was discovered as an X-ray source by the Uhuru satellite and it has been observed since then by every X-ray observatory. Due to its brightness and variability as well as the large observational archives, Vela X-1 is the Rosetta stone for studies of wind accretion onto neutron stars. We discuss the X-ray observational properties of the system in conjunction with the supergiant properties to test recent accretion models in high mass X-ray binaries, ranging from detailed descriptions of the wind acceleration (e.g., Sander et al. 2018) to modelling of the structure of the flow of matter close to the neutron star (e.g., EL Mellah, Keppens & Sundqvist 2018). We report new results on the impact of the wind clumpiness on the X-ray time variability and how the revised downwards wind speed implies dramatic consequences for the accretion process such as the formation of a wind-captured disc beyond the neutron star magnetosphere. Such a structure remains to be observed but its indirect signatures through jets or the torques it applies on the neutron star could well be within our observational grasp.

Trabajo presentado al Spanish X-ray Astronomy Meeting: 'present, future and synergies', celebrado en la Universidad de Alicante del 26 al 27 de noviembre de 2019., The eclipsing high mass X-ray binary Vela X-1 consists of an accreting X-ray pulsar orbiting an early type supergiant with an orbital period of ~ 9 days. It was discovered as an X-ray source by the Uhuru satellite and it has been observed since then by every X-ray observatory. Due to its brightness and variability as well as the large observational archives, Vela X-1 is the Rosetta stone for studies of wind accretion onto neutron stars. We discuss the X-ray observational properties of the system in conjunction with the supergiant properties to test recent accretion models in high mass X-ray binaries, ranging from detailed descriptions of the wind acceleration (e.g., Sander et al. 2018) to modelling of the structure of the flow of matter close to the neutron star (e.g., EL Mellah, Keppens & Sundqvist 2018). We report new results on the impact of the wind clumpiness on the X-ray time variability and how the revised downwards wind speed implies dramatic consequences for the accretion process such as the formation of a wind-captured disc beyond the neutron star magnetosphere. Such a structure remains to be observed but its indirect signatures through jets or the torques it applies on the neutron star could well be within our observational grasp., This meeting is supported by Conselleria d’Educació, Investigació, Cultura i Esport de la Generalitat Valenciana through the project AORG/2019/109 and by the Red de Infraestructuras de Astronomía through the project AYA2017-9068-REDI of the Ministerio de Ciencia, Innovación y Universidades.