Rotational modulation in RRs/Delta Scuti Star pulsation

Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Additional info

To appear in the Carnegie Observatories Astrophysics Series, Volume 5

Type

Scientific paper

Abstract

The 76 frequencies determined from Kepler measurements of the A-type star KIC 9700322 can be understood in a rather simple way as the radial fundamental and first overtone radial modes, a nonradial \ell = 2 quintuplet, stellar rotation and combinations of all of these. Two low-frequency peaks are found: f=0.160 c/d and a 2f peak. We show from a variety of arguments that the low-frequency peak, f, (rather than the 2f peak) is the rotational frequency. The corresponding prediction of slow rotation is confirmed by a spectrum from which v sin i = 19 \pm 1 km/s is obtained. During rotation, the brightness changes by 0.5 ppt (parts-per-thousand, peak-to-peak). The rotation also modulates the amplitudes of the two radial modes, leading to a small (but definite) variation in amplitude of 0.5% of their average values. Both the rotational brightness variations and the pulsation amplitudes form a double wave during rotation. The variations are in phase. The maximum pulsation amplitude occurs at the rotational phase with minimum brightness. Consequently, the 'normal' star KIC 9700322 behaves such as an extremely weak chemically peculiar star. Since such variations are also seen in some other A stars studied by Kepler, normal stars with a symmetric surface may not exist. The significance of this star is that even a simple, slowly rotating, radial pulsator already shows rotational brightness variations and modulation of the pulsation amplitude.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Rotational modulation in RRs/Delta Scuti Star pulsation 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 Rotational modulation in RRs/Delta Scuti Star pulsation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotational modulation in RRs/Delta Scuti Star pulsation will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-330418

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.