The CARMENES search for exoplanets around M dwarfs: Convective shift and starspot constraints from chromatic radial velocities

被引:35
作者
Baroch, D. [1 ,2 ]
Morales, J. C. [1 ,2 ]
Ribas, I. [1 ,2 ]
Herrero, E. [1 ,2 ]
Rosich, A. [1 ,2 ]
Perger, M. [1 ,2 ]
Anglada-Escude, G. [1 ,2 ]
Reiners, A. [3 ]
Caballero, J. A. [4 ]
Quirrenbach, A. [5 ]
Amado, P. J. [6 ]
Jeffers, S. V. [3 ]
Cifuentes, C. [4 ]
Passegger, V. M. [7 ,8 ]
Schweitzer, A. [7 ]
Lafarga, M. [1 ,2 ]
Bauer, F. F. [6 ]
Bejar, V. J. S. [9 ,10 ]
Colome, J. [1 ,2 ]
Cortes-Contreras, M. [4 ,11 ]
Dreizler, S. [3 ]
Galadi-Enriquez, D. [12 ]
Hatzes, A. P. [13 ]
Henning, Th. [14 ]
Kaminski, A. [5 ]
Kuerster, M. [14 ]
Montes, D. [15 ,16 ]
Rodriguez-Lopez, C. [6 ]
Zechmeister, M. [3 ]
机构
[1] CSIC, Inst Ciencies Espai ICE, Campus UAB,C Can Magrans S-N, Barcelona 08193, Spain
[2] Inst Estudis Espacials Catalunya IEEC, C Gran Capita 2-4, Barcelona 08034, Spain
[3] Georg August Univ, Inst Astrophys, Friedrich Hund Pl 1, D-37077 Gottingen, Germany
[4] ESAC, Ctr Astrobiol CSIC INTA, Camino Bajo Castillo S-N, Madrid 28692, Spain
[5] Heidelberg Univ, Zentrum Astron, Landessternwarte, Konigstuhl 12, D-69117 Heidelberg, Germany
[6] CSIC, Inst Astrofis Andalucia IAA, Glorieta Astron S-N, Granada 18008, Spain
[7] Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg, Germany
[8] Univ Oklahoma, Homer L Dodge Dept Phys & Astron, 440 West Brooks St, Norman, OK 73019 USA
[9] Inst Astrofis Canarias, Via Lactea S-N, Tenerife 38205, Spain
[10] Univ La Laguna, Dept Astrofis, Tenerife 38026, Spain
[11] Spanish Virtual Observ, Madrid, Spain
[12] Observ Calar Alto, Ctr Astron Hispano Aleman, Gergal 04550, Spain
[13] Thuringer Landesstenwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany
[14] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany
[15] Univ Complutense Madrid, Fac Ciencias Fis, Dept Fis Tierra & Astrofis, Madrid 28040, Spain
[16] Univ Complutense Madrid, Fac Ciencias Fis, IPARCOS UCM, Inst Fis Particulas & Cosmos UCM, Madrid 28040, Spain
关键词
convection; stars: late-type; starspots; stars: activity; techniques: radial velocities; LOW MASS STARS; STELLAR ACTIVITY; SOLAR GRANULATION; LINE ASYMMETRIES; YZ CMI; PLANETS; FLARE; VARIABILITY; ROTATION;
D O I
10.1051/0004-6361/202038213
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals.Aims. We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the identification of the key parameters that have an impact on the induced variability.Methods. We analyzed the effect of stellar activity on radial velocities as a function of wavelength by simulating the impact of the properties of spots, shifts induced by convective motions, and rotation. We focused our modeling effort on the active star YZ CMi (GJ 285), which was photometrically and spectroscopically monitored with CARMENES and the Telescopi Joan Oro.Results. We demonstrate that radial velocity curves at different wavelengths yield determinations of key properties of active regions, including spot-filling factor, temperature contrast, and location, thus solving the degeneracy between them. Most notably, our model is also sensitive to convective motions. Results indicate a reduced convective shift for M dwarfs when compared to solar-type stars (in agreement with theoretical extrapolations) and points to a small global convective redshift instead of blueshift.Conclusions. Using a novel approach based on simultaneous chromatic radial velocities and light curves, we can set strong constraints on stellar activity, including an elusive parameter such as the net convective motion effect.
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页数:12
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