Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (24) (Citation History)
· Refereed Citations to the Article
· Reads History
· Translate This Page
Differential photometry of magnetic faculae
Foukal, P.; Duvall, T., Jr.
AA(Atmospheric and Environmental Research, Inc., Cambridge, MA), AB(NASA, Goddard Space Flight Center, Tucson, AZ)
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 296, Sept. 15, 1985, p. 739-745. (ApJ Homepage)
Publication Date:
Solar Physics
NASA/STI Keywords:
Faculae, Near Infrared Radiation, Photosphere, Solar Magnetic Field, Stellar Spectrophotometry, Atmospheric Optics, Atmospheric Temperature, Fraunhofer Lines, Optical Thickness, Solar Atmosphere, Stellar Models
Bibliographic Code:


Previous photometric observations carried out at the KPNO vacuum telescope showed that faculae become clearly visible near disk center in the difference of two widely separated (green and red) continuum passbands. The authors present new observations extending this technique to the near-infrared, to demonstrate that the main factor determining the facular visibility is the difference in H- opacity between the continuum passbands. It is shown that the difference signal is directly sensitive to changes in the temperature gradient near tau0.5 = 1 between quiet photosphere and faculae. The measured facular temperature gradient is compared with that given by empirical facular models based on Fraunhofer line observations, and with theoretical predictions.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints