Discovery of magnetic fields in five DC white dwarfs

被引:5
|
作者
Berdyugin, Andrei V. [1 ]
Piirola, Vilppu [1 ]
Bagnulo, Stefano [2 ]
Landstreet, John D. [2 ,3 ]
Berdyugina, Svetlana V. [4 ,5 ,6 ]
机构
[1] Univ Turku, Dept Phys & Astron, Vesilinnantie 5, Turku 20014, Finland
[2] Armagh Observ & Planetarium, Coll Hill, Armagh BT61 9DG, North Ireland
[3] Univ Western Ontario, Dept Phys & Astron, 1151 Richmond St North, London, ON N6A 3K7, Canada
[4] Leibniz Inst Sonnenphys KIS, Schoneckstr 6, Freibirg, Germany
[5] Univ Svizzera Italiana, IRSOL Ist Ric Solari Aldo e Cele Dacco, Fac Informat, Via Patocci 57, Locarno, Switzerland
[6] Univ Svizzera Italiana, Euler Inst, Fac Informat, Via Santa 1, CH-6962 Lugano, Switzerland
基金
加拿大自然科学与工程研究理事会;
关键词
magnetic fields; white dwarfs; polarization; CIRCULAR-POLARIZATION; SPECTRAL EVOLUTION; ATMOSPHERE; SAMPLE; STARS;
D O I
10.1051/0004-6361/202245149
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
About half of white dwarfs (WDs) evolve to the DC state as they cool; the others become DQ or (temporarily?) DZ WDs. The recent magnetic survey of the local 20 pc volume has established a high frequency of magnetic fields among WDs older than 2-3 Gyr, demonstrating that in low- and average-mass WDs, the effects of magnetism become more common as they age, and the fields on average become stronger. However, the available statistics of WDs older than about 5 Gyr do not clearly establish how fields evolve beyond this age. We are carrying out a survey to clarify the occurrence of magnetism in DC-type WDs in order to better understand this late evolution. We use broadband filter polarimetry, arguably the most efficient way to detect magnetic fields in featureless WDs via continuum circular polarization. Here we report the discovery of a magnetic field in five DC WDs (of 23 observed), almost doubling the total sample of known magnetic WDs belonging to the DC spectral class.
引用
收藏
页数:6
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