THE EXTREME-ULTRAVIOLET EMISSION FROM SUN-GRAZING COMETS

Journal Article · Tue Nov 20 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/1/18· OSTI ID:22086347

Bryans, P ^[1]; Pesnell, W D ^[2]

---

1. ADNET Systems Inc., NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)
2. NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory has observed two Sun-grazing comets as they passed through the solar atmosphere. Both passages resulted in a measurable enhancement of extreme-ultraviolet (EUV) radiance in several of the AIA bandpasses. We explain this EUV emission by considering the evolution of the cometary atmosphere as it interacts with the ambient solar atmosphere. Molecules in the comet rapidly sublimate as it approaches the Sun. They are then photodissociated by the solar radiation field to create atomic species. Subsequent ionization of these atoms produces a higher abundance of ions than normally present in the corona and results in EUV emission in the wavelength ranges of the AIA telescope passbands.

• OSTI ID: 22086347
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 760; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
ATOMS
COMETS
ELEMENT ABUNDANCE
EVOLUTION
EXTREME ULTRAVIOLET RADIATION
IONIZATION
IONS
MOLECULES
PHOTON EMISSION
SOLAR ATMOSPHERE
SOLAR RADIATION
SUN
TELESCOPES