Publications

Publications of the
MOBSTER
Collaboration

Refereed papers by the Collaboration:

MOBSTER – VI. The crucial influence of rotation on the radio magnetospheres of hot stars
M. E. Shultz, S. P. Owocki, A. ud-Doula et al., 2022, MNRAS, 513, 1429

In this paper, we address gyrosynchrotron radio emission in magnetic hot stars. We present and analyse an exhaustive list of radio measurements of magnetic early-type stars available in the literature (131 stars, with 50 that are radio-bright). The dependance of gyrosynchrotron radiation on stellar rotation is examined. We also explore the relationship between radio luminosity and Hα emission, which suggests that radio emission may result from electrons that have been accelerated in centrifugally driven magnetic reconnection events.

MOBSTER – V. Discovery of a magnetic companion star to the magnetic β Cep pulsator HD 156424
M. E. Shultz, Th. Rivinius, G. A. Wade et al., 2021, MNRAS, 504, 4850

HD 156424, a previously known magnetic pulsator, is found to have a binary companion that is also magnetic, making this system only the second doubly-magnetic massive binary known to this day (the other being ɛ Lupi). The estimated magnetospheric extent of both components suggests that they are interacting.

MOBSTER – IV. Detection of a new magnetic B-type star from follow-up spectropolarimetric observations of photometrically selected candidates
A. David-Uraz, M. E. Shultz, V. Petit et al., 2021, MNRAS, 504, 4841

We report the first new detection of a magnetic field by the MOBSTER Collaboration in the late B-type star HD 38170. This detection was obtained in the context of a spectropolarimetric follow-up program that acquired data for 4 magnetic candidates with rotationally modulated light curves, yielding a detection rate that is greater than the overall incidence rate of magnetic OBA stars.

MOBSTER – III. HD 62658: a magnetic Bp star in an eclipsing binary with a non-magnetic ‘identical twin’
M. E. Shultz, C. Johnston, J. Labadie-Bartz et al., 2019, MNRAS, 490, 4154

We report the discovery of an eclipsing binary system comprising a late B-type magnetic star and a nearly identical twin: the only obvious difference between both stars is that the secondary is non-magnetic. This test case places important constraints on the origin of magnetic fields in stars with radiative envelopes.

MOBSTER – II. Identification of rotationally variable A stars observed with TESS in sectors 1-4
J. Sikora, A. David-Uraz, S. Chowdhury et al., 2019, MNRAS, 487, 4695

Using 2-minute cadence data from the first four sectors of TESS observations, we identify 134 high-probability candidate rotational variable A-type stars, of which a majority are classified in the literature as magnetic Ap stars. The light curve variations of rotationally modulated Ap stars differ quantitatively from those of rotationally modulated non-Ap stars, typically exhibiting higher amplitudes and longer periods.

Magnetic OB[A] Stars with TESS: probing their Evolutionary and Rotational properties (MOBSTER) – I. First-light observations of known magnetic B and A stars
A. David-Uraz, C. Neiner, J. Sikora et al., 2019, MNRAS, 487, 304

In this introductory paper, we present the MOBSTER Collaboration and its main goals, before analyzing the light curves of 19 previously known magnetic B- and A-type stars, highlighting their diversity and commonalities. 13 of them seem to exhibit rotational modulation in their light curves, allowing for refined period determinations.