Determination of Solar Radius and Earth’s Radius by Relativistic Matter Wave

Variations of Solar Radius: Observations with Rhessi

The Solar Aspect System (SAS) of the rotating (15 rpm) RHESSI spacecraft has three subsystems. Each of these measures the position of the limb by sampling the solar chord profile with a linear CCD and a narrow-bandwidth filter at 670 nm. With a plate scale of 1.7 arcsec/pixel, the precision of each of the six simultaneously observed limb positions is observed to be better than 50 mas, using fou...

Radius Mass Position of Radius

On Solar Radius Variation with magnetic Activity

In response to the claim by Dziembowski et al. (2001) that the solar radius decreases with magnetic activity at the rate of 1.5 km yr, we consider the theoretical question whether a radius variation is expected with the solar cycle. If the radius variation is caused by the magnetic pressure of toroidal flux tubes at the bottom of the convection zone, then the dynamo model of Nandy and Choudhuri...

Maximum mass-radius ratios for charged compact general relativistic objects

– Upper limits for the mass-radius ratio and total charge are derived for stable charged general relativistic matter distributions. For charged compact objects the mass-radius ratio exceeds the value 4/9 corresponding to neutral stars. General restrictions for the red shift and total energy (including the gravitational contribution) are also obtained. It is generally accepted today that black h...

Heliographic latitude dependence of the apparent solar radius

A brief outline is given of the advantages of the drift scan method and of the Danjon astrolabe for measuring the apparent solar radius. An analysis of 2111 measurements of the apparent semidiameter of the Sun made with a modified Danjon astrolabe at Santiago, Chile, shows a significant dependence of the observed semidiameter with the heliographic latitude. These results are confirmed by simila...