Related papers: New Insights into the T Tauri Binary Separation Di…
Although T Tauri is one of the most studied young objects in astronomy, the nature of its circumstellar environment remains elusive due, in part, to the small angular separation of its three components (North-South and South a-b are…
The Upper Scorpius OB association is the nearest region of recent massive star formation and thus an important benchmark for investigations concerning stellar evolution and planet formation timescales. We present nine EBs in Upper Scorpius,…
Given that a majority of stars form in multiple systems, in order to fully understand the star- and planet-formation processes we must seek to understand them in multiple stellar systems. With this in mind, we present an analysis of the…
Small planets ($R_{p} \leq 4 R_{\oplus}$) are divided into rocky super-Earths and gaseous sub-Neptunes separated by a radius gap, but the mechanisms that produce these distinct planet populations remain unclear. Binary stars are the only…
TESS is finding transiting planet candidates around bright, nearby stars across the entire sky. The large field-of-view, however, results in low spatial resolution, therefore multiple stars contribute to almost every TESS light curve.…
This paper uses statistical and $N$-body methods to explore a new mechanism to form binary stars with extremely large separations ($> 0.1\,{\rm pc}$), whose origin is poorly understood. Here, ultra-wide binaries arise via chance entrapment…
The recently discovered exoplanets in binary or higher-order multiple stellar systems sparked a new interest in the study of proto-planetary discs in stellar aggregations. Here we focus on disc solids, as they make up the reservoir out of…
The formation of very wide binaries, such as the alpha Cen system with Proxima (also known as alpha Centauri C) separated from alpha Centauri (which itself is a close binary A/B) by 15000 AU, challenges current theories of star formation,…
Binary systems are very common among field stars. While this relatively small number of planets in binaries is probably partly due to strong observational biases, there is, however, statistical evidence that planets are indeed less frequent…
Recent studies of the substellar population in the Taurus cloud have revealed a deficit of brown dwarfs (BD) compared to the Trapezium cluster population (Briceno et al 1998; Luhman 2000; Luhman et al 2003a; Luhman 2004). However, these…
I discuss results from the recent spectroscopic survey for solar-type pre-MS stars in the Lower Centaurus-Crux (LCC) and Upper Centaurus-Lupus (UCL) OB subgroups by Mamajek, Meyer, & Liebert (2002, AJ, 124, 1670). LCC and UCL are subgroups…
We study the interpretation of the mean surface density of stellar companions as a function of separation (or the two point correlation function of stars) in star-forming regions. First, we consider the form of the functions for various…
Observational results of young star-forming regions suggest that star clusters are completely mass segregated at birth. As a star cluster evolves dynamically, these initial conditions are gradually lost. For star clusters with single stars…
Almost all globular clusters (GCs) contain multiple populations consisting of stars with varying helium and light-element abundances. These populations include first-population stars, which exhibit similar chemical compositions to…
We present theoretical models for the evolution of T Tauri stars surrounded by circumstellar discs. The models include the effects of pre-main-sequence stellar and time dependent disc evolution, and incorporate the effects of stellar…
We have conducted a survey of young single and multiple systems in the Taurus-Auriga star-forming region with the Atacama Large Millimeter Array (ALMA), substantially improving both the spatial resolution and sensitivity with which…
The basic properties of the candidate binary cluster population in the Magellanic Clouds and Galaxy are similar. The fraction of candidate binary systems is $\sim$10% and the pair separation histogram exhibits a bimodal distribution…
To improve the statistics of hierarchical multiplicity, secondary components of wide nearby binaries with solar-type primaries were surveyed at the SOAR telescope for evaluating the frequency of subsystems. Images of 17 faint secondaries…
We present a study of 15 new brown dwarfs belonging to the $\sim7$ Myr old 25 Orionis group and Orion OB1a sub-association with spectral types between M6 and M9 and estimated masses between $\sim0.07$M$_\odot$ and $\sim0.01$ M$_\odot$. By…
Although the sample of exoplanets in binaries has been greatly expanded, the sample heterogeneity and observational bias are obstacles toward a clear figure of exoplanet demographics in the binary environment. To overcome the obstacles, we…