相关论文: Masses and Implications for Ages of Low-Mass Pre-M…

I have performed a search for young low-mass stars and brown dwarfs (BDs) in 2 regions encompassing a total area of 4 deg^2 in the Taurus star-forming region, discovering 15 new members of Taurus. In addition, I present 7 new members…

We present stellar rotation rates derived from Transiting Exoplanet Survey Satellite (TESS) light curves for stars in Upper Centaurus-Lupus (UCL; ~136 pc, ~16 Myr) and Lower Centaurus-Crux (LCC; ~115 pc, ~17 Myr). We find spot-modulated…

We model the mass accretion rate $\dot{M}$ to stellar mass $M_*$ correlation that has been inferred from observations of intermediate to upper mass T Tauri stars---that is $\dot{M} \propto M_*^{1.3 \pm 0.3}$. We explain this correlation…

We use high-signal-to-noise ($\sim$150-450), high resolution ($R{\sim}45,000$) Keck HIRES spectroscopy of 13 candidate post T Tauri stars to derive basic physical parameters, lithium abundances and radial velocities. We place our stars in…

M dwarfs are the most abundant stars in the Galaxy and exhibit diverse magnetic behaviours. Understanding their large-scale magnetic fields is essential to study stellar dynamos and assess the impact of magnetic activity on planetary…

During stellar evolution, especially in the PMS, stellar structure and rotation evolve significantly causing major changes in the dynamics and global flows of the star. We wish to assess the consequences of these changes on stellar dynamo,…

Hydrogen deuteride (HD) rotational line emission can provide reliable protoplanetary disk gas mass measurements, but it is difficult to observe and detections have been limited to three T-Tauri disks. No new data have been available since…

We present a rotational study of Post-T Tauri stars (PTTSs) in Lindroos systems, defined as binaries with early type primaries on the main-sequence (MS) and late-type secondaries on the pre-main-sequence (PMS) phase. The importance of this…

Determining the sequence of events in the formation of stars and planetary systems and their time-scales is essential for understanding those processes, yet establishing ages is fundamentally difficult because we lack direct indicators. In…

Context. Young loose nearby associations are unique samples of close (<150 pc), young (approx 5-100 Myr) pre-main sequence (PMS) stars. A significant number of members of these associations have been identified in the SACY collaboration. We…

The interplay between T Tauri stars and their circumstellar disks, and how this impacts the onset of planet formation has yet to be established. We studied a seemingly old T Tauri star, PDS 111, and its disk. We analyzed optical, infrared,…

The surface rotation rates of young solar-type stars vary rapidly with age from the end of the pre-main sequence through the early main sequence. Important changes in the dynamos operating in these stars may result from this evolution,…

We present the work in progress of a study based on photometric and spectroscopic observations of young Weak-line T Tauri and Post T Tauri stars just attiving on the Zero Age Main Sequence. This study is part of a project based on…

Interpreting the short-timescale variability of the accreting, young, low-mass stars known as Classical T Tauri stars remains an open task. Month-long, continuous light curves from the Transiting Exoplanet Survey Satellite (\textit{TESS})…

We present optical spectra of pre-main sequence (PMS) candidates around the H$\alpha$ region taken with the Southern African Large Telescope, SALT, in the low metallicity ($Z$) Galactic region Sh 2-284, which includes the open cluster…

The Classical T Tauri Star (CTTS) stage is a critical phase of the star and planet formation process. In an effort to better understand the mass accretion process, which can dictate further stellar evolution and planet formation, a…

(Abridged) Projected rotational velocities (vsini) have been measured for a sample of 145 stars with masses between 0.4 and >10 Msun (median mass 2.1 Msun) located in the Orion star-forming complex. These measurements have been supplemented…

The surface magnetic fields of pre-main-sequence stars and zero-age main-sequence stars are notably strong, resulting in the generation of numerous spots and the emission of bright chromospheric lines. Rotational variations in magnetic…

We present an analysis of high-resolution ($R \sim 50,000$) infrared K-band echelle spectra of 14 T Tauri stars in the Orion Nebula Cluster. We model Zeeman broadening in three magnetically sensitive \ion{Ti}{1} lines near $2.2\ \mu$m and…

We have conducted a survey of 17 wide (> 100 AU) young binary systems in Taurus with the Atacama Large Millimeter Array (ALMA) at two wavelengths. The observations were designed to measure the masses of circumstellar disks in these systems…