SIMBAD references

2018ApJ...852L...4L - Astrophys. J., 852, L4-L4 (2018/January-1)

Ultraviolet flux decrease under a grand minimum from IUE short-wavelength observation of solar analogs.

LUBIN D., MELIS C. and TYTLER D.

Abstract (from CDS):

We have identified a sample of 33 Sun-like stars observed by the International Ultraviolet Explorer (IUE) with the short-wavelength spectrographs that have ground-based detections of chromospheric Ca II H+K activity. Our objective is to determine if these observations can provide an estimate of the decrease in ultraviolet (UV) surface flux associated with a transition from a normal stellar cycle to a grand-minimum state. The activity detections, corrected to solar metallicity, span the range -5.16 logRHK^′^ -4.26, and eight stars have log RHK^′^ -5.00. The IUE-observed flux spectra are integrated over the wavelength range 1250-1910 Å, transformed to surface fluxes, and then normalized to solar B - V. These normalized surface fluxes show a strong linear relationship with activity RHK^′^ (R2 = 0.857 after three outliers are omitted). From this linear regression we estimate a range in UV flux of 9.3% over solar cycle 22 and a reduction of 6.9% below solar cycle minimum under a grand minimum. The 95% confidence interval in this grand-minimum estimate is 5.5%-8.4%. An alternative estimate is provided by the IUE observations of τ Cet (HD 10700), a star having strong evidence of being in a grand-minimum state, and this star's normalized surface flux is 23.0 ± 5.7% lower than solar cycle minimum.

Abstract Copyright: © 2017. The American Astronomical Society. All rights reserved.

Journal keyword(s): stars: activity - stars: solar-type - Sun: activity - Sun: UV radiation - ultraviolet: stars - ultraviolet: stars

Simbad objects: 35

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2019.09.20-06:17:56

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