Helioseismic evidence of two solar granulation timescales

Free access article

Issue		A&A Volume 443, Number 1, November III 2005


Page(s)		L11 - L14
Section		Letters
DOI		http://dx.doi.org/10.1051/0004-6361:200500191

A&A 443, L11-L14 (2005)
DOI: 10.1051/0004-6361:200500191

Letter

Helioseismic evidence of two solar granulation timescales

H. Vázquez Ramió¹, C. Régulo^{1, 2} and T. Roca Cortés^{1, 2}

¹ Instituto de Astrofísica de Canarias, 38200 La Laguna (Tenerife), Spain
e-mail: hvr@iac.es
² Dpto. de Astrofísica, Universidad de La Laguna, 38206 La Laguna (Tenerife), Spain
e-mail: crr@iac.es,trc@iac.es

(Received 14 July 2005 / Accepted 17 September 2005 )

Abstract
The signature of two different scales of solar granulation in the power spectrum of disk integrated irradiance time series is presented. The fitted timescales for granulation ( $\tau_{{\rm GR1}}\approx 237~{\rm s}$ and $\tau_{{\rm GR2}}\approx 62~{\rm s}$ ) are in good agreement with the characteristic lifetimes derived from recent image time series of the Sun's surface (Del Moro 2004); and probably linked to magnetic chromospheric structures such as bright points (Harvey et al. 1993).

Key words: Sun: helioseismology -- Sun: photosphere -- Sun: granulation -- Sun: activity

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