Why Zlatan Ibrahimović is Bigger Than Manchester United: Investigating Digital Traces in Co-branding Processes on Social Media Platforms

The purpose of this study is to examine the co-branding activity on social media platforms, particularly in regard to company-employee relationship. We conducted a case study of co-branding on Instagram involving the soccer club Manchester United and the soccer player Zlatan Ibrahimović. We performed sentiment and emotional tone analysis, assessed intersection of the audience and illustrated non-verbal communication used by social media users. We demonstrated how the soccer club failed to capitalize on co-branding activity as measured through consolidating the audience, generating consistent emotional response, and creating a coherent message. This paper contributes to social media management research by illustrating the difficulties associated with co-branding between personal and corporate brands as well asynchronous communication. Further, our use of digital traces and computational analysis illustrates how access to social media can illuminate research activities and provide insight about online communication

Transit Ly-α\alpha signatures of terrestrial planets in the habitable zones of M dwarfs

We modeled the transit signatures in the Lya line of a putative Earth-sized planet orbiting in the HZ of the M dwarf GJ436. We estimated the transit depth in the Lya line for an exo-Earth with three types of atmospheres: a hydrogen-dominated atmosphere, a nitrogen-dominated atmosphere, and a nitrogen-dominated atmosphere with an amount of hydrogen equal to that of the Earth. We calculated the in-transit absorption they would produce in the Lya line. We applied it to the out-of-transit Lya observations of GJ 436 obtained by the HST and compared the calculated in-transit absorption with observational uncertainties to determine if it would be detectable. To validate the model, we also used our method to simulate the deep absorption signature observed during the transit of GJ 436b and showed that our model is capable of reproducing the observations. We used a DSMC code to model the planetary exospheres. The code includes several species and traces neutral particles and ions. At the lower boundary of the DSMC model we assumed an atmosphere density, temperature, and velocity obtained with a hydrodynamic model for the lower atmosphere. We showed that for a small rocky Earth-like planet orbiting in the HZ of GJ436 only the hydrogen-dominated atmosphere is marginally detectable with the STIS/HST. Neither a pure nitrogen atmosphere nor a nitrogen-dominated atmosphere with an Earth-like hydrogen concentration in the upper atmosphere are detectable. We also showed that the Lya observations of GJ436b can be reproduced reasonably well assuming a hydrogen-dominated atmosphere, both in the blue and red wings of the Lya line, which indicates that warm Neptune-like planets are a suitable target for Lya observations. Terrestrial planets can be observed in the Lya line if they orbit very nearby stars, or if several observational visits are available.Comment: 17 pages, 12 figures, accepted for publication in Astronomy & Astrophysic