| Full text | |
| Author(s): |
Valio, Adriana
;
Araujo, Alexandre
;
Menezes, Fabian
Total Authors: 3
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 972, n. 1, p. 9-pg., 2024-09-01. |
| Abstract | |
While direct magnetic field measurements are rare for slowly rotating stars, spots observed during planetary transits provide a potential indicator of magnetic activity on stellar surfaces. Moreover, the rotation of the stellar surface can be probed by monitoring the spots' position with time in subsequent transits. This study investigates the dynamic interplay of rotational shear and stellar rotation rate in six stars of spectral types F to M, all hosting exoplanets observed by the CoRoT space mission, except for one binary star from Kepler. The analysis, facilitated by the ECLIPSE code, unveils the physical properties of stellar spots, including radius, intensity, temperature, and position. The five CoRoT stars exhibit spot characteristics consistent with those observed in solar type stars. The determination of a spot longitude during different transits allows for the inference of the star's differential rotation profile, revealing a decreasing trend of rotational shear with the mean stellar rotation period, given by Delta Omega proportional to P<overline>(-0.9) . This implies that, at least for slow rotators (mean rotation period >5 days), as stars age, their differential rotation decreases. Additionally, the six stars analyzed here seem to fall into two categories, according to their spot flux deficit: those with Delta F (spot) > 0.005 and those with Delta F (spot)< 0.002. (AU) | |
| FAPESP's process: | 18/04055-8 - High precision spectroscopy: from the first stars to planets |
| Grantee: | Jorge Luis Melendez Moreno |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 21/02120-0 - Investigation of high energy and plasma astrophysics phenomena, installation of the ASTRI-Mini Array & construction of the Cherenkov Telescope Array Small Size Telescopes (CTA-SSTs) |
| Grantee: | Elisabete Maria de Gouveia Dal Pino |
| Support Opportunities: | Special Projects |