Related papers: Far-Infrared Luminosity Bursts Trace Mass Accretio…
The far-IR range is a critical wavelength range to characterize the physical and chemical processes that transform the interstellar material into stars and planets. Objects in the earliest phases of stellar and planet evolution release most…
We demonstrate the feasibility of detecting directly low mass stars in unresolved super-star clusters with ages < 10 Myr using near-infrared spectroscopy at modest resolution (R ~ 1000). Such measurements could constrain the ratio of high…
The earliest phases of star formation are characterised by intense mass accretion from the circumstellar disk to the central star. One group of young stellar objects, the FU Orionis-type stars exhibit accretion rate peaks accompanied by…
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…
The closest examples of high-mass star birth occurs in deeply embedded environments at kiloparsec distances. Although much progress has been made, an observationally validated picture of the dominant processes which allows the central…
We have obtained time series observations of the Orion Nebula Cluster at 70 microns and 160 microns from the Herschel/PACS Photometer. This represents the first wide-field far-infrared photometric monitoring of a young star forming region.…
We select far-infrared (FIR-60 microns) and far-ultraviolet (FUV-1530 A) samples of nearby galaxies in order to discuss the biases encountered by monochromatic surveys (FIR or FUV). Very different volumes are sampled by each selection and…
Accretion bursts from low-mass young stellar objects (YSOs) are known for many decades. In recent years, the first accretion bursts of massive YSOs (MYSOs) have been observed. These phases of intense protostellar growth are of particular…
We determine the observational signatures of protostellar cores by coupling two-dimensional radiative transfer calculations with numerical hydrodynamical simulations that predict accretion rates that both decline with time and feature…
Outbursts due to dramatic increases in the mass accretion rate are the most extreme type of variability in young stellar objects. We searched for outbursts among 319 protostars in the Orion molecular clouds by comparing 3.6, 4.5, and 24…
We present a preliminary view of the protostellar mass-luminosity relation using current samples of protostars with dynamical mass estimates. To provide a lower limit to the expected luminosities, we adopt an empirical estimate for the…
The optical/near-IR stellar continuum carries unique information about the stellar population in a galaxy, its mass function and star-formation history. Star-forming regions display rich emission-line spectra from which we can derive the…
Massive stars have an impact on their surroundings from early in their formation until the end of their lives. However, very little is known about their formation. Episodic accretion may play a crucial role, but observations of these events…
It is now a widely held view that, in their formation and early evolution, stars build up mass in bursts. The burst mode of star formation scenario proposes that the stars grow in mass via episodic accretion of fragments migrating from…
How a star forms is a fundamental question in astrophysics. In the earliest stages of protostellar evolution high extinction prevents a direct study of the accretion processes and their temporal evolution. Monitoring the variations of the…
We study the formation and long-term evolution of primordial protostellar disks harbored by first stars using numerical hydrodynamics simulations in the thin-disk limit. The initial conditions are specified by pre-stellar cores with…
The protostellar luminosity function (PLF) is the present-day luminosity function of the protostars in a region of star formation. It is determined using the protostellar mass function (PMF) in combination with a stellar evolutionary model…
A long-standing problem in low-mass star formation is the "luminosity problem," whereby protostars are underluminous compared to the accretion luminosity expected both from theoretical collapse calculations and arguments based on the…
The idea that non steady accretion during the embedded phase of protostar evolution can produce the observed luminosity spread in the Herzsprung-Russell diagram (HRD) of young clusters has recently been called into question. Observations of…
We investigate the role of mass infall in the formation and evolution of protostars. To avoid ad hoc initial and boundary conditions, we consider the infall resulting self-consistently from modeling the formation of stellar clusters in…