PROPERTIES OF THE DIFFUSE NEUTRAL HELIUM IN THE INNER HELIOSPHERE
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
Sensitive SOLARC imaging spectropolarimetric observations from Haleakala reveal a diffuse coronal surface brightness in the He I 1083 nm line. A series of observations suggests that this signal originates from an 'inner source' of neutral helium atoms in the solar corona. Here, we explore the possibility that this cold coronal component originates from helium ions that are neutralized by the near-Sun dust and subsequently excited to the metastable 1s2s {sup 3} S state, which then scatters photons from the solar disk. This picture suggests a deficit of coronal dust inside about 2-4 R{sub sun} in order to account for both the flat radial brightness distribution and the small velocity line width of the observations. We find a strong correlation between the polarized He brightness and coronal white light brightness that supports the argument that electronic collisional excitation of the metastable helium triplet level is responsible for our polarization signal.
- OSTI ID:
- 21464628
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 2; Other Information: DOI: 10.1088/0004-637X/722/2/1411; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
BRIGHTNESS
DUSTS
HELIOSPHERE
HELIUM
HELIUM IONS
PHOTONS
SOLAR CORONA
SOLAR WIND
SUN
ATMOSPHERES
BOSONS
CHARGED PARTICLES
ELEMENTARY PARTICLES
ELEMENTS
FLUIDS
GASES
IONS
MAIN SEQUENCE STARS
MASSLESS PARTICLES
NONMETALS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RARE GASES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR WINDS