Simultaneous measurements of sunspot umbral oscillations in the photosphere, chromosphere, and transition region

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164890· OSTI ID:6570976

Thomas, J H; Lites, B W; Gurman, J B; Ladd, E F

Measurements of umbral oscillations in a sunspot were made simultaneously from space (with the SMM/UVSP instrument) in the C IV transition-region line and from the ground (with the tower telescope at NSO/sunspot) in spectral lines formed in the photosphere and chromosphere. The power spectra of velocity and intensity variations show multiple peaks in the 3 min band (4.5-10 mHz). A strong oscillation at 5.5 mHz is coherent between the chromosphere and transition region. Another strong oscillation mode at 7.5 mHz is coherent between the photosphere and transition region and appears to have a node in the chromosphere. The rms velocity in the 3 min band is a little over 12 km/sec in both the chromosphere and transition region, but the kinetic energy density is lower in the transition region (by a factor of 10 or more) due to the lower mass density there. These measurements of amplitude and phase of the waves at different heights provided a new, independent method of testing or fitting models of the vertical temperature distribution in the umbral chromosphere and transition regions. 14 references.

• Research Organization: C. E. K. Mees Observatory, Rochester, NY; High Altitude Observatory, Boulder, CO; NASA, Goddard Space Flight Center, Greenbelt, MD
• OSTI ID: 6570976
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 312; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHROMOSPHERE
DISTRIBUTION
MASS DISTRIBUTION
OSCILLATIONS
PHOTOSPHERE
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SPATIAL DISTRIBUTION
SPECTRA
STARSPOTS
STELLAR ACTIVITY
SUNSPOTS
TEMPERATURE DISTRIBUTION
ULTRAVIOLET SPECTRA