Stellar activity and brightness variations: A glimpse at the sun's history

Technical Report · Fri Jan 05 04:00:00 EST 1990

OSTI ID:6479319

Radick, R R; Lockwood, G W; Baliunas, S J

Radiometric measurements during the past decade from the Solar Maximum Mission and Number 7 satellites have shown that the total solar irradiance varies in step with the sun's 11-year magnetic activity cycle. Stellar observations from the Lowell and Mount Wilson observatories now confirm and elaborate this discovery. These measurements show that older stars similar to the sun tend to become brighter as their magnetic activity level increases, just as the sun does during its 11-year activity cycle. Younger stars, however, tend to become fainter as their magnetic activity level increases. This contrasting behavior suggests that the balance between the competing phenomena that influence solar brightness variability has shifted during the sun's lifetime.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6479319
• Report Number(s): AD-A-223985/3/XAB; GL-TR--90-0149
• Country of Publication: United States
• Language: English

Related Subjects

640102 -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SATELLITES
SOLAR ACTIVITY
SOLAR CONSTANT
SOLAR RADIATION
STARS
STELLAR ACTIVITY
STELLAR RADIATION
SUN
VARIATIONS