Journal
ASTROPHYSICAL JOURNAL
Volume 933, Issue 2, Pages -Publisher
IOP Publishing Ltd
DOI: 10.3847/1538-4357/ac7527
Keywords
-
Categories
Funding
- JSPS KAKENHI [21K13980]
- National Development and Reform Commission
- NASA Science Mission Directorate
- NASA [NAS 526555]
Ask authors/readers for more resources
Through investigating the relationship between rotation periods and photometric modulation amplitudes of main-sequence stars, it was found that using the convective turnover time or Rossby number as a scaling factor for rotation period can predict photometric modulation amplitudes effectively. Additionally, a rapid decrease in photometric modulation amplitudes with increasing Rossby number was observed, causing rotational modulation of some stars to be buried under photometric noise.
We investigate the relation between rotation periods P-rot and photometric modulation amplitudes R-per for approximate to 4000 Sun-like main-sequence stars observed by Kepler, using P-rot and R-per from McQuillan et al., effective temperature T-eff from LAMOST DR6, and parallax data from Gaia EDR3. As has been suggested in previous works, we find that P-rot scaled by the convective turnover time tau(c), or the Rossby number Ro, serves as a good predictor of R-per: R-per plateaus at around 1% in relative flux for 0.2 less than or similar to Ro/Ro(circle dot) less than or similar to 0.4, and decays steeply with increasing Ro for 0.4 less than or similar to Ro/Ro(circle dot) less than or similar to 0.8, where Ro(circle dot) denotes Ro of the Sun. In the latter regime we find d ln R-per/d ln Ro similar to 4.5 to -2.5, although the value is sensitive to detection bias against weak modulation and may depend on other parameters including T(eff )and surface metallicity. The existing X-ray and Ca II H and K flux data also show transitions at Ro/Ro(circle dot) - 0.4, suggesting that all these transitions share the same physical origin. We also find that the rapid decrease of R-per with increasing Ro causes rotational modulation of fainter Kepler stars with Ro/Ro(circle dot) greater than or similar to 0.6 to be buried under the photometric noise. This effect sets the longest P rot detected in the McQuillan et al. sample as a function of T-eff and obscures the signature of stalled spin down that has been proposed to set in around Ro/Ro(circle dot) similar to 1.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available