Related papers: FUors, EXors and the role of intermediate objects

We present new 12CO J=3-2 and HCN J=3-2 molecular line maps of the region surrounding the young star AR 6 using the 15 metre James Clerk Maxwell Telescope. AR 6 was previously found to be a double source with both components exhibiting…

Stars do not simply pop up on the main sequence. Before the stars arrive on the zero-age main sequence, they form in the collapses of molecular clouds, gain matter through accretion processes, and compress their cores until hydrogen can…

FU Ori type objects (FUors) are decades-long outbursts of accretion onto young stars that are strong enough to viscously heat disks so that the disk outshines the central star. We construct models for FUor objects by calculating emission…

The results of the EDGES (Experiment to Detect the Global EoR Signature) experiment (Bowman et al., 2018) is interpreted as the beginning of compression stage of primary density fluctuations in a mini halo. Estimates of the mass of these…

One of the most attractive events in the pre-main sequence evolution is the FU Orionis (FUor) outburst. Because only a small number of FUor stars have been detected to date, photometric and spectral studies of every new object are of great…

Non-planetary bodies provide valuable insight into our current under- standing of planetary formation and evolution. Although these objects are challeng- ing to detect and characterize, the potential information to be drawn from them has…

FU Orionis stars (FUors) are young low-mass eruptive stars that are thought to be accreting at high rates. They could give rise to soft X-ray emission from accretion shocks, but their X-ray properties are largely unknown. We report the…

EX Lupi-type objects (EXors) form a sub-class of T Tauri stars, defined by sudden sporadic flare-ups of 1-5 magnitudes at optical wavelengths. These eruptions are attributed to enhanced mass accretion from the circumstellar disk to the…

This review addresses the state of research that employs astronomical (remote sensing) observations of solids ("dust") in young circumstellar disks to learn about planet formation. The intention is for it to serve as an accessible,…

Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense…

Only a dozen confirmed FU Orionis-type young outbursting stars (FUors) are known today; this explains the interest in the recent FUor eruption of 2MASS J06593158-0405277. Its outburst and expected decline will be subject to numerous studies…

In this paper, I review how optical spectro-interferometry has become a particularly well suited technique to study the close environment of young stars, by spatially resolving both their IR continuum and line emission regions. I summarize…

Gaia19fct is one of the Gaia-alerted eruptive young stars that has undergone several brightening events. We conducted monitoring observations using multi-filter optical and near-infrared photometry, as well as near-infrared spectroscopy, to…

Extreme star formation includes star formation in starbursts and regions forming super star clusters. We survey the current problems in our understanding of the star formation process in starbursts and super star clusters - initial mass…

Young stars exhibit variability due to changes in the gas accretion rate onto them, an effect that should be quite significant in the early stages of their formation. As protostars are embedded within their natal cloud, this variability may…

In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if a more fundamental level of elementary particles exists, in the form of preons, stability may be…

Protoplanetary disks are quasi-steady structures whose evolution and dispersal determine the environment for planet formation. I review the theory of protoplanetary disk evolution and its connection to observations. Substantial progress has…

While accreting through a circumstellar disk, young stellar objects are observed to undergo sudden and powerful accretion events known as FUor or EXor outbursts. Although such episodic accretion is considered to be an integral part of the…

Neutron stars have long been regarded as extra-terrestrial laboratories from which we can learn about extreme energy density matter at low temperatures. In this article, I highlight some of the recent advances made in astrophysical…

We aim to understand the effect of stellar evolution on the evolution of protoplanetary disks. We focus in particular on the disk evolution around intermediate-mass (IM) stars, which evolve more rapidly than low-mass ones. We numerically…