相关论文: Rotation and variability of young very low mass ob…
The regulation of angular momentum is one of the key processes for our understanding of stellar evolution. In contrast to solar-mass stars, very low mass (VLM) objects and brown dwarfs are believed to be fully convective. This may lead to…
The evolution of angular momentum is a key to our understanding of star formation and stellar evolution. The rotational evolution of solar-mass stars is mostly controlled by magnetic interaction with the circumstellar disc and angular…
The regulation of angular momentum is one of the key processes for our understanding of stellar evolution. The rotational evolution of solar-mass stars is mainly determined by the magnetic interaction with their circumstellar disk and…
We present a survey for photometric variability in young, low-mass brown dwarfs with the Spitzer Space Telescope. The 23 objects in our sample show robust signatures of youth and share properties with directly-imaged exoplanets. We present…
The study of rotation and activity in low-mass stars or brown dwarfs of spectral classes M and L has seen enormous progress during the last years. I summarize the results from different works that measured activity, rotation, and sometimes…
One of the characteristic features of low-mass stars is their propensity to shed large amounts of angular momentum throughout their evolution. This distinguishs them from brown dwarfs which remain fast rotators over timescales of gigayears.…
We explore the rotation and activity of very low mass (VLM) objects by means of a photometric variability study. Our targets in the vicinity of Epsilon Ori belong to the OriOB1b population in the Orion star-forming complex. In this region…
We review the current state of our knowledge concerning the rotation and angular momentum evolution of young stellar objects and brown dwarfs from a primarily observational view point. Periods are typically accurate to 1% and available for…
We examine the evolution of low-mass star and brown dwarf eclipsing binaries. These objects are rapid rotators and are believed to shelter large magnetic fields. We suggest that reduced convective efficiency, due to fast rotation and large…
We present a photometric variability survey of young planetary-mass objects using the New Technology Telescope in the Js and Ks bands. Surface gravity plays an important role in the atmospheric structure of brown dwarfs, as young low…
This chapter aims at providing the most complete review of both the emerging concepts and the latest observational results regarding the angular momentum evolution of young low-mass stars and brown dwarfs. In the time since Protostars &…
Context. Very low-mass (VLM) stars and brown dwarfs (BDs) present a different rotational behaviour from their solar mass counter-parts. Aims. We investigate the rotational evolution of young VLM stars and BDs using Monte Carlo simulations…
We report the results of a $J$-band survey for photometric variability in a sample of young, low-gravity objects using the New Technology Telescope (NTT) and the United Kingdom InfraRed Telescope (UKIRT). Surface gravity is a key parameter…
The discovery of large numbers of young low-mass stars and brown dwarfs over the last decade has made it possible to investigate star formation and early evolution in a previously unexplored mass regime. In this review, we begin by…
Up to now, most planet search projects have concentrated on F to K stars. In order to considerably widen the view, we have stated a survey for planets of old, nearby brown dwarfs and very low mass stars. Using UVES, we have observed 26…
Brown dwarfs constitute a missing link between low-mass stars and giant planets. Their atmospheres display chemical species typical of planets, and one could wonder whether they also have weather-like patterns. While brown dwarf surface…
Massive early-type stars vary; low-mass late-type brown dwarfs vary, too. I will make a short, but illustrative, summary of my previous studies on stellar and sub-stellar photometric variability (including the discovery of the most variable…
Precise measurements of the fundamental properties of low-mass stars and brown dwarfs are key to understanding the physics underlying their formation and evolution. While there has been great progress over the last decade in studying the…
This article represents a short review of the variability characteristics of young stellar objects. Variability is a key property of young stars. Two major origins may be distinguished: a scaled-up version of the magnetic activity seen on…
I present the results of a multiyear survey of very low mass stars and brown dwarfs, at high spectral resolution. The spectra were gathered with the HIRES echelle at the Keck Observatory. Some of these objects are stellar and others are…