Probing The Solar Surface: The Oblateness and Astrophysical Consequences

Details Probing The Solar Surface: The Oblateness and Astrophysical Consequences Probing The Solar Surface: The Oblateness and Astrophysical Consequences

Oct 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009apj...703.1791r&link_type=abstract

The Astrophysical Journal, Volume 703, Issue 2, pp. 1791-1796 (2009).

Astronomy and Astrophysics

Astronomy

2

Astrometry, Relativity, Sun: Rotation

Scientific paper

Based on historical records, the Sun's dimensions are temporally dependent. Until the recent past, varying dimensions were keenly disputed. Recent accurate observations have removed the doubt, whether from direct limb observations or from helioseismology f-modes analysis. A shrinking or an expanding shape is ultimately linked to solar activity, as even a small variation in the solar radius causes variations in gravitational energy. Based on accurate space- and ground-based observations, we will argue that the oblateness of the Sun is time dependent. Indeed, considering the first two shape coefficients, we can interpret such a temporal variation as a change in the relative importance of the hexadecapolar term, i.e., at the time of high activity, only the dipolar moment c 2 has a significant effect, but at the time of low activity, c 4 is predominant; this results in a decrease of the total value of the oblateness. The combination of the two terms leads to a solar oblateness varying along with solar activity. More studies are needed to get accurate measurements from space, which will provide us with the unique opportunity to study detailed changes of global solar properties.

Affiliated with

Also associated with

No associations

Rating

Probing The Solar Surface: The Oblateness and Astrophysical Consequences does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Probing The Solar Surface: The Oblateness and Astrophysical Consequences, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Probing The Solar Surface: The Oblateness and Astrophysical Consequences will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-805219