What change slowly occurs during the main-sequence lifetime of a star?
A) As hydrogen is used up in the core, the fusion rate decreases and reduces the luminosity.
B) It gathers more gas from interstellar space, increasing its mass and hence the luminosity.
C) Its core temperature slowly increases, increasing the fusion rate and hence the luminosity.
D) As the solar wind blows material into space, the decreasing mass reduces pressure in the core, which in turn reduces the fusion rate and the luminosity.
Question 2
The Doppler technique can be used to estimate the semimajor axis of a planet's orbit by
A) measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law.
B) measuring the speed at which the star orbits the mutual center-of-mass of the star and planet, and using Newton's theory of gravity.
C) measuring the asymmetries in the velocity curve.
D) measuring the amount by which the starlight is reduced when the planet transits.
Body plan of an echinoderm, as represented by a sea star.
This jumping spider's main ocelli (center pair) are very acute.
Balmer Lines in the Spectrum of a Star
Splash blending occurs when the ethanol is added to a tanker with gasoline and is mixed as the ...
Sequence Series Arithmatic Progression Problem
Postreplication repair occurs if DNA replication