A Magnetic Snapshot Survey of F-Type Stars

Seach, J.; Marsden, S. C.; Carter, B. D.; Neiner, C.; Folsom, C. P.; Mengel, M. W.; Oksala, M. E.; Buysschaert, B.

doi:10.1093/mnras/staa1107

Cited by 10 publications

(6 citation statements)

References 173 publications

(268 reference statements)

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“…The Kolmogorov-Smirnov test which we perform after the optimisation gives D = 0.14 which corresponds to a p-value of 0.035. It might be related to a fact that some low-mass A stars might have dynamo (Featherstone et al 2009;Thomson-Paressant et al 2021;Seach et al 2020;Zwintz et al 2020).…”

Section: Resultsmentioning

confidence: 99%

Testing the fossil field hypothesis: could strongly magnetized OB stars produce all known magnetars?

Макаренко

Igoshev

Kholtygin

2021

Monthly Notices of the Royal Astronomical Society

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Stars of spectral types O and B produce neutron stars (NSs) after supernova explosions. Most of NSs are strongly magnetized including normal radio pulsars with B ∝ 1012 G and magnetars with B ∝ 1014 G. A fraction of 7–12 per cent of massive stars are also magnetized with B ∝ 103 G and some are weakly magnetized with B ∝ 1 G. It was suggested that magnetic fields of NSs could be the fossil remnants of magnetic fields of their progenitors. This work is dedicated to study this hypothesis. First, we gather all modern precise measurements of surface magnetic fields in O, B, and A stars. Secondly, we estimate parameters for lognormal distribution of magnetic fields in B stars and found μB = 2.83 ± 0.1 log10 (G), σB = 0.65 ± 0.09 for strongly magnetized and μB = 0.14 ± 0.5 log10 (G), $\sigma =0.7_{-0.27}^{+0.57}$ for weakly magnetized. Third, we assume that the magnetic field of pulsars and magnetars have 2.7-dex difference in magnetic fields and magnetars represent 10 per cent of all young NSs and run population synthesis. We found that it is impossible to simultaneously reproduce pulsars and magnetars populations if the difference in their magnetic fields is 2.7 dex. Therefore, we conclude that the simple fossil origin of the magnetic field is not viable for NSs.

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Section: Resultsmentioning

confidence: 99%

Testing the fossil field hypothesis: could strongly magnetized OB stars produce all known magnetars?

Макаренко

Igoshev

Kholtygin

2021

Monthly Notices of the Royal Astronomical Society

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“…Magnetic fields have been investigated and measured in other A stars, however most of them have weak magnetic field strengths (see e.g. Aurière et al 2007, Lignières et al 2009, Petit et al 2011, Blazère et al 2016a,b, Neiner et al 2017, Seach et al 2020. Interestingly, Aurière et al (2007) found a lack of stellar magnetic fields with strengths between 300 and a few Gauss, which is now commonly termed as the 'magnetic desert'.…”

Section: Introductionmentioning

confidence: 99%

Rotational modulation in A and F stars: magnetic stellar spots or convective core rotation?

Henriksen

Antoci

Saio

et al. 2023

Monthly Notices of the Royal Astronomical Society

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The Kepler mission revealed a plethora of stellar variability in the light curves of many stars, some associated with magnetic activity or stellar oscillations. In this work, we analyse the periodic signal in 162 intermediate-mass stars, interpreted as Rossby modes and rotational modulation - the so-called hump & spike feature. We investigate whether the rotational modulation (spike) is due to stellar spots caused by magnetic fields or due to Overstable Convective (OsC) modes resonantly exciting g modes, with frequencies corresponding to the convective core rotation rate. Assuming that the spikes are created by magnetic spots at the stellar surface, we recover the amplitudes of the magnetic fields, which are in good agreement with theoretical predictions. Our data show a clear anti-correlation between the spike amplitudes and stellar mass and possibly a correlation with stellar age, consistent with the dynamo-generated magnetic fields theory in (sub)-surface convective layers. Investigating the harmonic behaviour, we find that for 125 stars neither of the two possible explanations can be excluded. While our results suggest that the dynamo-generated magnetic field scenario is more likely to explain the spike feature, we assess further work is needed to distinguish between the two scenarios. One method for ruling out one of the two explanations is to directly observe magnetic fields in hump & spike stars. Another would be to impose additional constraints through detailed modelling of our stars, regarding the rotation requirement in the OsC mode scenario or the presence of a convective-core (stellar age).

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“…The Kolmogorov-Smirnov test which we perform after the optimisation gives 𝐷 = 0.14 which corresponds to a p-value of 0.035. It might be related to a fact that some low-mass A stars might have dynamo (Featherstone et al 2009;Thomson-Paressant et al 2021;Seach et al 2020;Zwintz et al 2020).…”

Section: Resultsmentioning

confidence: 99%

Testing the fossil field hypothesis: could strongly magnetised OB stars produce all known magnetars?

Makarenko,

Igoshev,

Kholtygin

2021

Preprint

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Stars of spectral types O and B produce neutron stars (NSs) after supernova explosions. Most of NSs are strongly magnetised including normal radio pulsars with 𝐵 ∝ 10 12 G and magnetars with 𝐵 ∝ 10 14 G. A fraction of 7-12 per cent of massive stars are also magnetised with 𝐵 ∝ 10 3 G and some are weakly magnetised with 𝐵 ∝ 1 G. It was suggested that magnetic fields of NSs could be the fossil remnants of magnetic fields of their progenitors. This work is dedicated to study this hypothesis. First, we gather all modern precise measurements of surface magnetic fields in O, B and A stars. Second, we estimate parameters for log-normal distribution of magnetic fields in B stars and found 𝜇 𝐵 = 2.83±0.1 log 10 (G), 𝜎 𝐵 = 0.65±0.09 for strongly magnetised and 𝜇 𝐵 = 0.14 ± 0.5 log 10 (G), 𝜎 = 0.7 0.57 −0.27 for weakly magnetised. Third, we assume that the magnetic field of pulsars and magnetars have 2.7 DEX difference in magnetic fields and magnetars represent 10 per cent of all young NSs and run population synthesis. We found that it is impossible to simultaneously reproduce pulsars and magnetars populations if the difference in their magnetic fields is 2.7 DEX. Therefore, we conclude that the simple fossil origin of the magnetic field is not viable for NSs.

show abstract

A Magnetic Snapshot Survey of F-Type Stars

Cited by 10 publications

References 173 publications

Testing the fossil field hypothesis: could strongly magnetized OB stars produce all known magnetars?

Testing the fossil field hypothesis: could strongly magnetized OB stars produce all known magnetars?

Rotational modulation in A and F stars: magnetic stellar spots or convective core rotation?

Testing the fossil field hypothesis: could strongly magnetised OB stars produce all known magnetars?

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