scholarly journals Photometric light curves for ten rapidly rotating stars in Alpha Persei, the Pleiades, and the field

1993 ◽  
Vol 105 ◽  
pp. 269 ◽  
Author(s):  
Charles F. Prosser ◽  
Rudolph E. Schild ◽  
John R. Stauffer ◽  
Burton F. Jones
Keyword(s):  
Light Curves ◽  
Rotating Stars ◽  
Alpha Persei ◽  
Rapidly Rotating Stars

scholarly journals Constraining the oblateness of transiting planets with photometry and spectroscopy

2020 ◽  
Vol 497 (3) ◽  
pp. 3484-3492
Author(s):  
B Akinsanmi ◽  
S C C Barros ◽  
N C Santos ◽  
M Oshagh ◽  
L M Serrano
Keyword(s):  
Light Curve ◽  
Equilibrium Shape ◽  
Giant Planet ◽  
Light Curves ◽  
Spin Orbit ◽  
Rotating Stars ◽  
Transiting Planets ◽  
Planetary Rotation ◽  
Spectroscopic Signatures ◽  
Rapidly Rotating Stars

ABSTRACT Rapid planetary rotation can cause the equilibrium shape of a planet to be oblate. While planetary oblateness has mostly been probed by examining the subtle ingress and egress features in photometric transit light curves, we investigate the effect of oblateness on the spectroscopic Rossiter–McLaughlin (RM) signals. We found that a giant planet, with planet-to-star radius ratio of 0.15 and Saturn-like oblateness of 0.098, can cause spectroscopic signatures with amplitudes up to 1.1 m s−1 which is detectable by high-precision spectrographs such as ESPRESSO. We also found that the spectroscopic oblateness signals are particularly amplified for transits across rapidly rotating stars and for planets with spin-orbit misalignment thereby making them more prominent than the photometric signals at some transit orientations. We compared the detectability of oblateness in photometry and spectroscopy and found that photometric light curves are more sensitive to detecting oblateness than the spectroscopic RM signals mostly because they can be sampled with higher cadence to better probe the oblateness ingress and egress anomaly. However, joint analyses of the light curve and RM signal of a transiting planet provides more accurate and precise estimate of the planet’s oblateness. Therefore, ESPRESSO alongside ongoing and upcoming photometric instruments such as TESS, CHEOPS, PLATO, and JWST will be extremely useful in measuring planet oblateness.

scholarly journals Rossby Waves in Astrophysics

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
T. V. Zaqarashvili ◽  
M. Albekioni ◽  
J. L. Ballester ◽  
Y. Bekki ◽  
L. Biancofiore ◽  
...  
Keyword(s):  
Large Scale ◽  
Rossby Waves ◽  
Magnetic Activity ◽  
Future Research ◽  
Rotating Stars ◽  
Spatial And Temporal Scales ◽  
Physical Role ◽  
Astrophysical Objects ◽  
Exoplanetary Atmospheres ◽  
Rapidly Rotating Stars

AbstractRossby waves are a pervasive feature of the large-scale motions of the Earth’s atmosphere and oceans. These waves (also known as planetary waves and r-modes) also play an important role in the large-scale dynamics of different astrophysical objects such as the solar atmosphere and interior, astrophysical discs, rapidly rotating stars, planetary and exoplanetary atmospheres. This paper provides a review of theoretical and observational aspects of Rossby waves on different spatial and temporal scales in various astrophysical settings. The physical role played by Rossby-type waves and associated instabilities is discussed in the context of solar and stellar magnetic activity, angular momentum transport in astrophysical discs, planet formation, and other astrophysical processes. Possible directions of future research in theoretical and observational aspects of astrophysical Rossby waves are outlined.

scholarly journals Learning about Stellar Dynamos from Long–term Photometry of Starspots

1991 ◽  
Vol 130 ◽  
pp. 353-369 ◽  
Author(s):  
Douglas S. Hall
Keyword(s):  
Differential Rotation ◽  
Rotation Period ◽  
Turnover Time ◽  
Rotating Stars ◽  
Photometric Variability ◽  
Solar Type ◽  
Magnetic Cycles ◽  
The Many ◽  
Rapidly Rotating Stars

AbstractSpottedness, as evidenced by photometric variability in 277 late-type binary and single stars, is found to occur when the Rossby number is less than about 2/3. This holds true when the convective turnover time versus B–V relation of Gilliland is used for dwarfs and also for subgiants and giants if their turnover times are twice and four times longer, respectively, than for dwarfs. Differential rotation is found correlated with rotation period (rapidly rotating stars approaching solid-body rotation) and also with lobe-filling factor (the differential rotation coefficient k is 2.5 times larger for F = 0 than F = 1). Also reviewed are latitude extent of spottedness, latitude drift during a solar-type cycle, sector structure and preferential longitudes, starspot lifetimes, and the many observational manifestations of magnetic cycles.

scholarly journals P-modes in rapidly rotating stars: Looking for regular patterns in synthetic asymptotic spectra

2010 ◽  
Vol 331 (9-10) ◽  
pp. 1053-1056 ◽  
Author(s):  
F. Lignières ◽  
B. Georgeot ◽  
J. Ballot
Keyword(s):  
Rotating Stars ◽  
Rapidly Rotating Stars ◽  
Regular Patterns

scholarly journals Pulsations of rapidly rotating stars

2015 ◽  
Vol 579 ◽  
pp. A116 ◽  
Author(s):  
R.-M. Ouazzani ◽  
I. W. Roxburgh ◽  
M.-A. Dupret
Keyword(s):  
Rotating Stars ◽  
Rapidly Rotating Stars

The Lack of Blue Supergiants in NGC 7419, a Red Supergiant-rich Galactic Open Cluster with Rapidly Rotating Stars

2003 ◽  
Vol 126 (3) ◽  
pp. 1415-1422 ◽  
Author(s):  
Genevive Caron ◽  
Anthony F. J. Moffat ◽  
Nicole St-Louis ◽  
Gregg A. Wade ◽  
John B. Lester
Keyword(s):  
Open Cluster ◽  
Rotating Stars ◽  
Rapidly Rotating Stars
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