The dramatic change of the fossil magnetic field of HD 190073: evidence of the birth of the convective core in a Herbig star?

被引：23

作者：

Alecian, E. ^{[1
]}

Neiner, C. ^{[1
]}

Mathis, S. ^{[1
,2
]}

Catala, C. ^{[1
]}

Kochukhov, O. ^{[3
]}

Landstreet, J. ^{[4
,5
]}

机构：

[1] Univ Paris Diderot, UPMC Univ, Observ Paris, LESIA,CNRS, F-92195 Meudon, France

[2] Univ Paris Diderot, CNRS, CEA, Lab AIM,DSM,IRFU,SAp,Ctr Saclay, F-91191 Gif Sur Yvette, France

[3] Uppsala Univ, Dept Phys & Astron, S-75120 Uppsala, Sweden

[4] Armagh Observ, Armagh BT61 9DG, North Ireland

[5] Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada

来源：

ASTRONOMY & ASTROPHYSICS | 2013年 / 549卷

关键词：

stars: early-type; stars: pre-main sequence; stars: magnetic field; stars: evolution; stars: individual: HD 190073; A-TYPE STARS; MASSIVE STARS; DYNAMO; GENERATION; MODELS; BODIES;

D O I：

10.1051/0004-6361/201220796

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

In the context of the ESPaDOnS and Narval spectropolarimetric surveys of Herbig Ae/Be stars, we discovered and then monitored the magnetic field of HD 190073 over more than four years, from 2004 to 2009. Our observations all displayed similar Zeeman signatures in the Stokes V spectra, indicating that HD 190073 hosted an aligned dipole, stable over many years, consistent with a fossil origin. We obtained new observations of the star in 2011 and 2012 and detected clear variations of the Zeeman signature on timescales of days to weeks, indicating that the configuration of its field has changed between 2009 and 2011. Such a sudden change of external structure of a fossil field has never previously been observed in any intermediate or high-mass star. HD 190073 is an almost entirely radiative pre-main sequence star, probably hosting a growing convective core. We propose that this dramatic change is the result of the interaction between the fossil field and the ignition of a dynamo field generated in the newly-born convective core.

引用

页数：4

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