相关论文: Stellar activity mimics a habitable-zone planet ar…
We report the discovery of HATS-2b, the second transiting extrasolar planet detected by the HATSouth survey. HATS-2b is moving on a circular orbit around a V=13.6 mag, K-type dwarf star (GSC 6665-00236), at a separation of 0.0230 \pm 0.0003…
Beyond orbital periods of 10 days, there is a dearth of known transiting gas giants. On longer orbits, planets are less affected by their host star, and become ideal probes of planet formation, migration and evolution. We report the…
We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available…
The ``sub-Jovian desert" ($2{\lesssim}R_{\rm p}{\lesssim}10 \ R_{\oplus}$, periods $\lesssim$3 days) is sparsely populated but no longer empty. Recent surveys have revealed that planets residing in the desert are dense (${\rho}{\gtrsim}1$…
We present here the detection of a system of four low-mass planets around the bright (V=5.5) and close-by (6.5 pc) star HD219134. This is the first result of the Rocky Planet Search program with HARPS-N on the TNG in La Palma. The inner…
Searches for periodicity in time series are often done with models of periodic signals, whose statistical significance is assessed via false alarm probabilities or Bayes factors. However, a statistically significant periodic model might not…
The ubiquity of M dwarf stars combined with their low masses and luminosities make them prime targets in the search for nearby, habitable exoplanets. We investigate the effects of starspot-induced radial velocity (RV) jitter on detection…
The rotation periods of the host stars of extrasolar planets have been assessed against those of the Mt. Wilson stars, open cluster stars, and evolutionary stellar models that include rotation. They appear to be normal, modulo certain…
Since identifying the gap in the H-R Diagram (HRD) marking the transition between partially and fully convective interiors, a unique type of slowly pulsating M dwarf has been proposed. These unstable M dwarfs provide new laboratories in…
The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the…
Abridged: We measured photometric and spectroscopic $P_{\rm rot}$ for a large sample of nearby bright M dwarfs with spectral types from M0 to M9, as part of our continual effort to fully characterize the Guaranteed Time Observation…
A rotation rate and X-ray luminosity analysis is presented for rapidly rotating single and binary M-dwarf systems. X-ray luminosities for the majority of both single & binary M-dwarf systems with periods below $\simeq 5-6$ days (equatorial…
Star-planet interactions play, among other things, a crucial role in planetary orbital configurations by circularizing orbits, aligning the star and planet spin and synchronizing stellar rotation with orbital motions. This is especially…
Interactions between stellar and planetary magnetic fields are expected to produce observable radio and optical signals modulated by their orbital periods, but direct detections remain elusive. We analyze 17 years of spectroscopic data of…
The star HD 147379 was recently announced as a host of a low-mass exoplanet by Reiners et al. (2017). That announcement included a discussion of the possible detection of a periodic signal in the radial velocity observations around 21.1…
Evidence suggesting an observable magnetic interaction between a star and its hot Jupiter appears as a cyclic variation of stellar activity synchronized to the planet's orbit. In this study, we monitored the chromospheric activity of 7…
While planets between the size of Uranus and Saturn are absent within the Solar System, the star K2-24 hosts two such planets, K2-24b and c, with radii equal to $5.4~R_E$ and $7.5~R_E$, respectively. The two planets have orbital periods of…
Features of the development of activity cycles in the solar-type stars and fast-rotating cool dwarfs have been considered for 65 stars observed in some decades. Cycles with duration of 7-18 years compared to the solar cycle were found for…
GJ 887 is a bright M dwarf in the solar neighborhood with two currently reported nontransiting exoplanets with periods of $9~\mathrm{d}$ and $21~\mathrm{d,}$ along with an additional unconfirmed signal at $50~\mathrm{d}$. We reanalyzed the…
The Mount Wilson Ca HK survey revealed magnetic activity variations in a large sample of solar-type stars with timescales ranging from 2.5 to 25 years. This broad range of cycle periods is thought to reflect differences in the rotational…