# Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties (MOBSTER) - I. First-light observations of known magnetic B and A stars

## TL;DR

This paper introduces the MOBSTER collaboration, analyzing TESS data of known magnetic B and A stars to determine their rotational periods and photometric behavior, aiming to enhance understanding of their evolution and rotation.

## Contribution

It presents first-light results from TESS observations of magnetic B and A stars, providing precise rotational periods and proposing strategies to expand the sample for evolutionary studies.

## Key findings

- Derived precise rotational periods from TESS light curves.
- Compared new periods with previously published values.
- Discussed photometric phenomenology of magnetic massive and intermediate-mass stars.

## Abstract

In this paper we introduce the MOBSTER collaboration and lay out its scientific goals. We present first results based on the analysis of nineteen previously known magnetic O, B and A stars observed in 2-minute cadence in sectors 1 and 2 of the Transiting Exoplanet Survey Satellite (TESS) mission. We derive precise rotational periods from the newly obtained light curves and compare them to previously published values. We also discuss the overall photometric phenomenology of the known magnetic massive and intermediate-mass stars and propose an observational strategy to augment this population by taking advantage of the high-quality observations produced by TESS.