Evidence of Increasing Acoustic Emissivity at High Frequency with Solar Cycle 23 in Sun-as-a-star Observations

Journal Article · Wed Sep 16 04:00:00 EDT 2009 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3246563· OSTI ID:21322924

Simoniello, R; Finsterle, W ^[1]; Garcia, R A ^[2]; Salabert, D; Jimenez, A ^[3]

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1. PMOD/WRC Switzerland Physikalisch-Meteorologisches Observatorium Davos-World Radiation Center, 7260 Davos Dorf (Switzerland)
2. Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, CEA, IRFU, SAp, centre de Saclay, F-91191, Gif-sur-Yvette (France)
3. IAC, Instituto de Astrofisica de Canarias, 38205, La Laguna, Tenerife (Spain)

We used long high-quality unresolved (Sun-as-a-star observations) data collected by GOLF and VIRGO instruments on board the ESA/NASA SOHO satellite to investigate the amplitude variation with solar cycle 23 in the high-frequency band (5.7<{nu}<6.3 mHz). We found an enhancement of acoustic emissivity over the ascending phase of about 18{+-}3 in velocity observations and a slight enhancement of 3{+-}2 in intensity. Mode conversion from fast acoustic to fast magneto-acoustic waves could explain the enhancement in velocity observations. These findings open up the possibility to apply the same technique to stellar intensity data, in order to investigate stellar-magnetic activity.

• OSTI ID: 21322924
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1170; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMPLITUDES
ASTROPHYSICS
EMISSIVITY
ESA
MAGNETIC FIELDS
MHZ RANGE
MODE CONVERSION
NASA
PHOTOMETRY
SEISMOLOGY
SOLAR ACTIVITY
SOLAR CYCLE
SOUND WAVES
SUN
VARIATIONS
VELOCITY