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Title: 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 activity indicators (including the H{sub β}, He I D{sub 3}, Na I D{sub 1}, D{sub 2}, H{sub α}, 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 Hα}/E {sub Hβ} values suggest that the emission of the Balmer 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.
Authors:
;  [1]
  1. Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China)
Publication Date:
OSTI Identifier:
22340021
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 147; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BALMER LINES; DATA; DWARF STARS; EMISSION; INDICATORS; MODULATION; RESOLUTION; ROTATION; SPECTRA; STARS; SURFACES; TRIPLETS