相关论文: Stellar Activity Manifesting at a One Year Alias E…

Stars of stellar type later than about M3.5 are believed to be fully convective and therefore unable to support magnetic dynamos like the one that produces the 11-year solar cycle. Because of their intrinsic faintness, very few late M stars…

Red Dwarfs (RDs) are the most common, low-mass stars (<=0.5 M_sun) in the Solar neighbourhood, and probably in the Universe as well. Most (likely all) young RDs are magnetically active, and therefore it is impossible to measure their radial…

The Transiting Exoplanet Survey Satellite (TESS) mission identified a potential 0.88 REarth planet with a period of 7.577 days, orbiting the nearby M1V star GJ 341 (TOI 741.01). This system has already been observed by the James Webb Space…

Radial-velocity (RV) planet searches are often polluted by signals caused by gas motion at the star's surface. Stellar activity can mimic or mask changes in the RVs caused by orbiting planets, resulting in false positives or missed…

In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during…

We report intensive monitoring of the activity variability in the H$\alpha$ line for 10 Sun-like stars using the 1.88-m reflector at Okayama Branch Office, Subaru Telescope, during the last four years 2019-2022. Our aim was to investigate…

The obliquity between the stellar spin axis and the planetary orbit, detected via the Rossiter-McLaughlin (RM) effect, is a tracer of the formation history of planetary systems. While obliquity measurements have been extensively applied to…

We report on the discovery and validation of a transiting long-period mini-Neptune orbiting a bright (V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 RSun, M = 1.10 MSun). The planet was identified in data from the Transiting Exoplanet Survey…

Stellar activity variability is one of the main obstacles to the detection of Earth-like planets using the RV method. The aim of this work is to measure the effect of activity in the spectra of M dwarfs and detect activity-sensitive lines…

Radial velocity measurements showed evidence that the M dwarf GL 581 might host a planet, GL 581d, in the so-called "habitable zone" of the star. A study of Halpha in GL 581 demonstrated that changes in this activity indicator correlated…

Stellar variability impacts radial velocities at various timescales and therefore the detectability of exoplanets and the mass determination based on this technique. It is necessary to implement systematic studies, to delineate the current…

In this article we present the case of HD 41004 AB, a system composed of a K0V star and a 3.7-magnitude fainter M-dwarf companion separated by only 0.5 arcsec. An analysis of CORALIE radial-velocity measurements has revealed a variation…

We present a study of the variation timescales of the chromospheric activity indicator H$\alpha$ on a sample of 13 fully-convective, active mid-to-late M stars with masses between 0.1--0.3 solar masses. Our goal was to determine the…

We present 20 years of radial velocity (RV) measurements of the M1 dwarf Gl15A, combining 5 years of intensive RV monitoring with the HARPS-N spectrograph with 15 years of archival HIRES/Keck RV data. We carry out an MCMC-based analysis of…

The signatures of planets hosted by M dwarfs are more readily detected with transit photometry and radial velocity methods than those of planets around larger stars. Recently, transit photometry was used to discover seven planets orbiting…

The magnetic chemically peculiar Ap stars exhibit an extreme spread of rotational velocities, the reason of which is not well understood. Ap stars with rotational periods of 50 days or longer are know as super-slowly rotating Ap (ssrAp)…

Periodic radial velocity variations in the nearby M-dwarf star Gl411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08…

We present the analysis of the entire HARPS observations of three stars that host planetary systems: HD1461, HD40307, and HD204313. The data set spans eight years and contains more than 200 nightly averaged velocity measurements for each…

A radial velocity (RV) survey to detect central stars in binary systems was carried out between 2002 and 2004. De Marco et al. (2004) reported that 10 out of 11 monitored stars exhibited strong RV variability, but periods were not detected.…

We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra, and compared to…