THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION

Christian, Damian J; Arias, Tersi; Mathioudakis, Mihalis; Jess, David B; Jardine, Moira

doi:10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)

Title: THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION

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Abstract

We investigate if the super-saturation phenomenon observed at X-ray wavelengths for the corona exists in the chromosphere for rapidly rotating late-type stars. Moderate resolution optical spectra of fast-rotating EUV- and X-ray-selected late-type stars were obtained. Stars in {alpha} Per were observed in the northern hemisphere with the Isaac Newton 2.5 m telescope and Intermediate Dispersion Spectrograph. Selected objects from IC 2391 and IC 2602 were observed in the southern hemisphere with the Blanco 4 m telescope and R-C spectrograph at CTIO. Ca II H and K fluxes were measured for all stars in our sample. We find the saturation level for Ca II K at log (L{sub CaK}/L{sub bol}) = -4.08. The Ca II K flux does not show a decrease as a function of increased rotational velocity or smaller Rossby number as observed in the X-ray. This lack of 'super-saturation' supports the idea of coronal stripping as the cause of saturation and super-saturation in stellar chromospheres and coronae, but the detailed underlying mechanism is still under investigation.

Authors:

Christian, Damian J; Arias, Tersi ^[1]; Mathioudakis, Mihalis; Jess, David B ^[2]; Jardine, Moira ^[3]

Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States)
Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, Belfast BT7 1NN (United Kingdom)
School of Physics and Astronomy, North Haugh, St. Andrews KY169SS (United Kingdom)

Publication Date:: Sat Sep 10 00:00:00 EDT 2011

OSTI Identifier:: 21584875

Resource Type:: Journal Article

Journal Name:: Astrophysical Journal

Additional Journal Information:: Journal Volume: 738; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/738/2/164; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X

Country of Publication:: United States

Language:: English

Subject:: 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; SATURATION; STARS; STELLAR CHROMOSPHERES; ATMOSPHERES; STELLAR ATMOSPHERES

Citation Formats


                    Christian, Damian J, Arias, Tersi, Mathioudakis, Mihalis, Jess, David B, and Jardine, Moira. THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION.  United States: N. p., 2011. 
        Web.  doi:10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).

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                    Christian, Damian J, Arias, Tersi, Mathioudakis, Mihalis, Jess, David B, & Jardine, Moira. THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION.  United States.  https://doi.org/10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)

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                    Christian, Damian J, Arias, Tersi, Mathioudakis, Mihalis, Jess, David B, and Jardine, Moira. 2011.  
        "THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION".  United States.  https://doi.org/10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).

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@article{osti_21584875,

  title        = {THE SEARCH FOR SUPER-SATURATION IN CHROMOSPHERIC EMISSION},

  author       = {Christian, Damian J and Arias, Tersi and Mathioudakis, Mihalis and Jess, David B and Jardine, Moira},

  abstractNote = {We investigate if the super-saturation phenomenon observed at X-ray wavelengths for the corona exists in the chromosphere for rapidly rotating late-type stars. Moderate resolution optical spectra of fast-rotating EUV- and X-ray-selected late-type stars were obtained. Stars in {alpha} Per were observed in the northern hemisphere with the Isaac Newton 2.5 m telescope and Intermediate Dispersion Spectrograph. Selected objects from IC 2391 and IC 2602 were observed in the southern hemisphere with the Blanco 4 m telescope and R-C spectrograph at CTIO. Ca II H and K fluxes were measured for all stars in our sample. We find the saturation level for Ca II K at log (L{sub CaK}/L{sub bol}) = -4.08. The Ca II K flux does not show a decrease as a function of increased rotational velocity or smaller Rossby number as observed in the X-ray. This lack of 'super-saturation' supports the idea of coronal stripping as the cause of saturation and super-saturation in stellar chromospheres and coronae, but the detailed underlying mechanism is still under investigation.},

  doi          = {10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},

  url          = {https://www.osti.gov/biblio/21584875},
  journal      = {Astrophysical Journal},

  issn         = {0004-637X},

  number       = 2,

  volume       = 738,

  place        = {United States},

  year         = {Sat Sep 10 00:00:00 EDT 2011},

  month        = {Sat Sep 10 00:00:00 EDT 2011}

}

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Journal Article:

https://doi.org/10.1088/0004-637X/738/2/164; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)

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