CHROMOSPHERIC ACTIVITY AND ROTATIONAL MODULATION ON THE YOUNG, SINGLE K2 DWARF LQ Hya

High-resolution echelle spectra of LQ Hya, obtained during several observing runs from 2006 to 2012, have been analyzed to study its chromospheric activity. Using the spectral subtraction technique, we derived information about chromospheric activity of LQ Hya from several optical chromospheric acti...

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Bibliographic Details
Published in:The Astronomical journal 2014-02, Vol.147 (2), p.1-10
Main Authors: Cao, Dong-Tao, Gu, Sheng-Hong
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BALMER LINES
DATA
DWARF STARS
EMISSION
Equivalence
Flares
INDICATORS
Infrared
MODULATION
RESOLUTION
ROTATION
Rotational
SPECTRA
STARS
Surface chemistry
SURFACES
TRIPLETS
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Summary:High-resolution echelle spectra of LQ Hya, obtained during several observing runs from 2006 to 2012, have been analyzed to study its chromospheric activity. Using the spectral subtraction technique, we derived information about chromospheric activity of LQ Hya from several optical chromospheric activity indicators (including the H sub( beta ), HeI D sub(3), Na I D sub(1), D sub(2), H sub( alpha ), and Ca II infrared triplet (IRT) lines). No optical flares were found during our observations. The equivalent widths (EWs) of the excess emissions in the chromospheric activity lines have been measured. The ratios of EW sub(8542)/EW sub(8498) are generally small, which indicates that the Ca II IRT emission arises from plage-like regions, while the E sub(H alpha )/ E sub(H beta ) values suggest that the emission of the Baimer lines is due to both plage and prominence structures for the observations in 2012. We find that clear rotational modulation of chromospheric emission exists, which suggests the presence and change of chromospheric active regions over the surface of LQ Hya. Moreover, the active regions were associated with the photospheric spots in spatial structure.
ISSN:0004-6256
1538-3881
1538-3881
DOI:10.1088/0004-6256/147/2/38