More recent measurements taken using ground-based telescopes have indicated a rounder shape than Dicke suggested.
The new RHESSI analysis, published online this week in the journal Science Express, offers magnetic activity as an explanation for why the sun occasionally appears more oblate, and bolsters the idea that its true shape is more rounded.
"We found that the sun was about as flat as the surface rotation predicts," Hudson said via email.
Jeffrey Kuhn, associate director of the Institute for Astronomy at the University of Hawaii and a former colleague of Dicke's, said the new study "has a surprising result, which contradicts existing space and ground measurements."
But Kuhn, who was not involved in the new study, said the technique the RHESSI team used is not a reliable measure of the sun's shape.
"So far it is unclear, at least to me, that their ad hoc analysis is telling us what the sun is really doing," he said.
Study co-author Hudson argued that Kuhn's criticism might partly be "based on the fact that if we are right—and we think we are—some of his early work with the legendary Dicke may have been misinterpreted."
But Hudson agrees that more work needs to be done to confirm his team's results.
"We have six years of data and have only analyzed three months' worth so far," Hudson said.
"The finding that rotation dominates the solar shape is, in a sense, not so surprising," he added.
"But it cleans up a messy observational picture and opens the way for really important things."
Starry Yardstick
Martin Asplund of the Max Planck Institute for Astrophysics in Garching, Germany, wrote a commentary for Science about the solar information divide.
Asplund pointed out that uncertainty appears to be the norm in studies of the sun.
Researchers have been retooling estimates of heavy elements in the sun's composition for a number of years, for example, and those data frequently conflict with interpretations of physics in the sun's atmosphere.
That's disappointing for astronomers seeking to rely on the sun as an "astronomical yardstick" for understanding the composition and physics of other stars, he wrote.
"Consensus will only occur when both sides have convincingly demonstrated that their analysis really is reliable and robust, which requires quite some more work."
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