Chromospheric emission of solar-type stars with asteroseismic ages
Chromospheric emission of solar-type stars with asteroseismic ages
复制标题
具有星震年龄的太阳型恒星的色层发射
DOI：
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发表时间：
2019
影响因子：
4.8
通讯作者：
H. Bruntt
中科院分区：
文献类型：
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作者：
R. Booth;K. Poppenhaeger;C. Watson;V. Silva Aguirre;D. Stello;H. Bruntt
由于磁制动驱动的恒星自旋下降，恒星的磁活动在冷却恒星的主序期内衰减。对于较年轻的恒星来说，色球发射的演化已经得到了很好的研究，但在主序列中确定较老的冷星的年龄的困难，使得过去对较老恒星的此类研究变得复杂。在这里，我们报告了26颗主序冷星的色球Ca、II H和K线的测量结果，这些冷星的恒星年龄大于十亿年，光谱类型为F和G型。我们发现，对于G星和仍然有对流包层的较冷的F型星，磁场活动在恒星年龄超过1Gyr时继续减少。我们的磁活动测量没有显示出磁制动机制失速的证据，据报道，对于G型和F型恒星，磁制动机制是恒星自转与年龄的关系。我们还发现，我们的样本中冷F星的测量的$R^{PRIME}_{MATHROM{HK}}$指示值低于通常的年龄-活动关系的预测值，这些关系主要是根据年轻星团的数据校准的。我们的结论是，在单独的光谱类型箱中，色球的磁活动与恒星年龄有很好的相关性，即使是对老恒星来说也是如此。
Stellar magnetic activity decays over the main-sequence life of cool stars due to the stellar spin-down driven by magnetic braking. The evolution of chromospheric emission is well studied for younger stars, but difficulties in determining the ages of older cool stars on the main sequence have complicated such studies for older stars in the past. Here, we report on chromospheric Ca ii H and K line measurements for 26 main-sequence cool stars with asteroseismic ages older than a gigayear and spectral types F and G. We find that for the G stars and the cooler F-type stars that still have convective envelopes the magnetic activity continues to decrease at stellar ages above 1 Gyr. Our magnetic activity measurements do not show evidence for a stalling of the magnetic braking mechanism, which has been reported for stellar rotation versus age for G- and F-type stars. We also find that the measured $R^{prime }_{mathrm{ HK}}$ indicator value for the cool F stars in our sample is lower than predicted by common age–activity relations that are mainly calibrated on data from young stellar clusters. We conclude that, within individual spectral type bins, chromospheric magnetic activity correlates well with stellar age even for old stars.
DOI：
10.1088/0004-637x/749/2/152
发表时间：
2012-02
期刊：
The Astrophysical Journal
影响因子：
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作者：
S. Mathur;T. Metcalfe;M. Woitaszek;H. Bruntt;G. Verner;J. Christensen-Dalsgaard;J. Christensen-Dalsgaard;O. Creevey;G. Doğan;G. Doğan;S. Basu;C. Karoff;C. Karoff;D. Stello;T. Appourchaux;T. Campante;T. Campante;W. Chaplin;R. García;T. Bedding;O. Benomar;A. Bonanno;S. Deheuvels;Y. Elsworth;P. Gaulme;J. Guzik;R. Handberg;S. Hekker;S. Hekker;W. Herzberg;M. Monteiro;L. Piau;P. Quirion;C. Régulo;C. Régulo;M. Roth;D. Salabert;A. Serenelli;Michael Thompson;R. Trampedach;T. White;J. Ballot;I. Brandao;J. Molenda–Żakowicz;H. Kjeldsen;J. Twicken;K. Uddin;B. Wohler
通讯作者：
S. Mathur;T. Metcalfe;M. Woitaszek;H. Bruntt;G. Verner;J. Christensen-Dalsgaard;J. Christensen-Dalsgaard;O. Creevey;G. Doğan;G. Doğan;S. Basu;C. Karoff;C. Karoff;D. Stello;T. Appourchaux;T. Campante;T. Campante;W. Chaplin;R. García;T. Bedding;O. Benomar;A. Bonanno;S. Deheuvels;Y. Elsworth;P. Gaulme;J. Guzik;R. Handberg;S. Hekker;S. Hekker;W. Herzberg;M. Monteiro;L. Piau;P. Quirion;C. Régulo;C. Régulo;M. Roth;D. Salabert;A. Serenelli;Michael Thompson;R. Trampedach;T. White;J. Ballot;I. Brandao;J. Molenda–Żakowicz;H. Kjeldsen;J. Twicken;K. Uddin;B. Wohler
影响因子：
4.9
作者：
Aguirre, Victor Silva;Lund, Mikkel N.;Rendle, Ben
通讯作者：
Rendle, Ben