J/A+A/711/A128 Magnetic delta Scuti candidates (Paul+, 2026)
Determining the incidence rate of magnetic delta Scuti candidates with CoRoT.
Paul G., Neiner C., Catala C., Labadie-Bartz J.
<Astron. Astrophys. 711, A128 (2026)>
=2026A&A...711A.128P 2026A&A...711A.128P (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Rotational velocities ; Optical
Keywords: asteroseismology - stars: magnetic field -
stars: variables: delta Scuti
Abstract:
delta Scuti stars are pulsating stars constituting the delta Scuti
instability strip in the Hertzsprung-Russell (HR) diagram, which
consists of A and F stars of various evolutionary stages. They are in
the transition region between high-mass hot stars and low-mass
solar-like stars, making understanding their magnetic properties
essential to painting a complete picture of magnetism across the HR
diagram. Furthermore, discovering magnetic delta Scuti stars allows
for magneto-asteroseismology, which can be used to determine the
internal rotation profile, internal magnetic field strength, and the
efficiency of mixing and transport processes more accurately than
classical asteroseismology.
To date, magnetic fields have been detected at the surface of 13 delta
Scuti stars. However, the overall incidence rate of magnetism in these
stars remains unknown. Fossil magnetic fields are detected in 10% of
OBA stars. The goal of this work is to find out if it is the same for
delta Scuti stars.
We investigated the incidence rate of surface magnetic fields among
delta Scuti stars using photometric data from the CoRoT space mission.
We analyzed long-duration (∼5 months) light curves of ∼1750 delta
Scuti stars to search for pulsations and rotational modulation - a
photometric signature that indicates chemical or temperature spots at
the stellar surface, usually caused by magnetic fields.
We identified 147 rotational variables that we designate as magnetic
candidates, thus potentially increasing the known population of
magnetic delta Scuti stars drastically and suggesting an incidence
rate of fossil magnetic fields in delta Scuti stars similar to the
incidence rate in OBA stars in general. Our analysis also revealed a
few delta Scuti-gamma Dor hybrid stars and four binary stars in the
sample. We determined the rotation periods and projected rotation
velocities of the magnetic candidates in order to select suitable
targets for follow-up spectropolarimetric observations aimed at
confirming and characterizing their magnetic fields.
Description:
We present a catalog of magnetic delta Scuti candidates identified
from CoRoT photometric observations. Magnetic candidates are
identified using rotational modulation and the rotation frequencies
are reported. The target positions are taken from CoRoT observations
and are used to crossmatch with Gaia DR3 to provide Gaia source IDs.
The catalog is intended to investigate the magnetic delta Scuti
candidates with spectropolarimetric follow-up observations.
The catalog contains 147 candidate magnetic delta Scuti stars among
the CoRoT variable stars catalogue. For each source we provide the
CoRoT identifier, Gaia DR3 source identifier, equatorial coordinates
(J2000), and the extracted rotation frequency f_rot derived from the
analysis of the rotational modulation.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tableb1.dat 55 147 Candidate magnetic delta Scuti stars among the
CoRoT variable stars catalogue
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See also:
B/corot : CoRoT observation log (N2-4.4) (CoRoT 2016)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- CoRoT CoRoT identifier
11- 29 I19 --- GaiaDR3 Gaia DR3 source identifier
31- 40 F10.6 deg RAdeg Right Ascension (J2000)
42- 50 F9.6 deg DEdeg Declination (J2000)
52- 55 F4.2 d-1 frot Rotation frequency
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Acknowledgements:
Gautam Paul, gautam.paul(at)obspm.fr
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 29-May-2026