Related papers: Time-variable electromagnetic star-planet interact…
Close-in massive planets interact with their host stars through tidal and magnetic mechanisms. In this paper, we review circumstantial evidence for star-planet interaction as revealed by the photospheric magnetic activity in some of the…
The time series of total solar irradiance (TSI) satellite observations since 1978 provided by ACRIM and PMOD TSI composites are studied. We find empirical evidence for planetary-induced forcing and modulation of solar activity. Power…
Pulsating variable $\delta$ Scuti stars are intermediate-mass stars with masses in the range of $1-3$ $M_{\odot}$ and spectral types between $A2$ and $F2$. They can be found at the intersection of the Cepheid instability strip with the main…
We report in this paper a new exponential relation distance of planets in the newly discovered exoplanetary system of the Trappist-1 star, and we comment on near orbital mean motion resonances among the seven planets. We predict that…
{\delta} Scuti variables are found at the intersection of the classical instability strip and the main sequence on the Hertzsprung-Russell diagram. With space-based photometry providing millions of light-curves of A-F type stars, we can now…
The spatiotemporal variation in tropical air-sea interaction is investigated by applying a simple model that considers the fundamental dynamics in tropical oceans. The model decomposes sea surface temperature anomaly (SSTA) variation into a…
We investigate the electromagnetic interaction of a relativistic stellar wind with a planet or a smaller body in orbit around the star. This may be relevant to objects orbiting a pulsar, such as PSR B1257+12 and PSR B1620-26 that are…
Circumbinary Planets (CBPs) can be misaligned with their host binary stars. Orbital dynamics, simulations, and recent observations of proto-planetary disks all suggest that the planet can stably orbit in a plane perpendicular to that of an…
We present the continuation of a systematic search for new southern Galactic symbiotic stars, selecting candidates from the SuperCOSMOS H$\alpha$ Survey and 2MASS. Follow-up spectroscopy with the Southern African Large Telescope (SALT) was…
Tidal interactions are one of the primary drivers of orbital evolution for massive planets with short orbital periods. Tidal dissipation within host stars can cause the orbits of such planets to decay. However, the mechanisms of tidal…
The TRAPPIST-1 planetary system is a favorable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the forthcoming James Webb Space Telescope (JWST). A possible obstacle…
Symbiotic binary stars typically consist of a white dwarf (WD) that accretes material from the wind of a companion red giant. Orbital periods for these binaries are on the order of years, and their relatively small optical outbursts tend to…
While not detected yet, pairs of exoplanets in the 1:1 mean motion resonance probably exist. Low eccentricity, near-planar orbits, which in the comoving frame follow the horseshoe trajectories, are one of the possible stable configurations.…
We have obtained CO(1-0) observations for a sample of 37 interacting galaxy systems, chosen from a parent sample of optically-selected interacting galaxies. The sample observed here spans a large range of interaction strengths and star…
Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot…
The discovery of terrestrial exoplanets orbiting in habitable zones around nearby stars has been one of the significant developments in modern astronomy. More than a dozen such planets, like Proxima Centauri b and TRAPPIST-1 e, are in…
Space weather in exoplanetary systems, driven by transient stellar emissions such as flares, coronal mass ejections, and stellar proton events, can significantly influence planetary habitability and the long-term evolution of atmospheres.…
We present a semi-analytic model atmosphere for close-in exoplanets that captures the essential physics of phase curves: orbital and viewing geometry, advection, and re-radiation. We calibrate the model with the well-characterized…
W Serpentids and Double Periodic Variables (DPVs) are candidates for close interacting binaries in a non-conservative evolutionary stage; while W Serpentids are defined by high-excitation ultraviolet emission lines present during most…
We are studying the influence of stellar multiplicity on exoplanet systems, in particular systems that have been detected via radial-velocity searches. We are in particular interested in the closest companions as they would have a strong…