Outstanding Issues on Pulsations in Young Stars

2003 ◽  
pp. 245-255
Author(s):  
M. Marconi ◽  
F. Palla
Keyword(s):  
Young Stars

A WIYN Lithium Survey for Young Stars in the λ Orionis Star-Forming Region

1999 ◽  
Vol 118 (5) ◽  
pp. 2409-2423 ◽  
Author(s):  
Christopher J. Dolan and Robert D. Mathieu
Keyword(s):  
Young Stars ◽  
Star Forming

scholarly journals The Observational Evidence for Accretion

1997 ◽  
Vol 182 ◽  
pp. 391-405 ◽  
Author(s):  
Lee Hartmann
Keyword(s):  
Large Range ◽  
Observational Evidence ◽  
Young Stars ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
T Tauri ◽  
Accretion Rates ◽  
Low Mass ◽  
Stellar Magnetospheres ◽  
Mass Ejection

Outflows from low-mass young stellar objects are thought to draw upon the energy released by accretion onto T Tauri stars. I briefly summarize the evidence for this accretion and outline present estimates of mass accretion rates. Young stars show a very large range of accretion rates, and this has important implications for both mass ejection and for the structure of stellar magnetospheres which may truncate T Tauri disks.

scholarly journals Double trouble: Gaia reveals (proto)planetary systems that may experience more than one dense star-forming environment

2020 ◽  
Vol 501 (1) ◽  
pp. L12-L17
Author(s):  
Christina Schoettler ◽  
Richard J Parker
Keyword(s):  
Planetary Systems ◽  
Young Star ◽  
Young Stars ◽  
Orion Nebula ◽  
External Effects ◽  
Star Forming ◽  
Star Forming Regions ◽  
Ejection Process ◽  
Runaway Stars

ABSTRACT Planetary systems appear to form contemporaneously around young stars within young star-forming regions. Within these environments, the chances of survival, as well as the long-term evolution of these systems, are influenced by factors such as dynamical interactions with other stars and photoevaporation from massive stars. These interactions can also cause young stars to be ejected from their birth regions and become runaways. We present examples of such runaway stars in the vicinity of the Orion Nebula Cluster (ONC) found in Gaia DR2 data that have retained their discs during the ejection process. Once set on their path, these runaways usually do not encounter any other dense regions that could endanger the survival of their discs or young planetary systems. However, we show that it is possible for star–disc systems, presumably ejected from one dense star-forming region, to encounter a second dense region, in our case the ONC. While the interactions of the ejected star–disc systems in the second region are unlikely to be the same as in their birth region, a second encounter will increase the risk to the disc or planetary system from malign external effects.

scholarly journals SEDBYS: A python-based SED Builder for Young Stars

SoftwareX ◽  
2021 ◽  
Vol 14 ◽  
pp. 100687
Author(s):  
Claire L. Davies
Keyword(s):  
Young Stars

scholarly journals Emission from Magnetized Accretion Disks around Young Stars

2017 ◽  
Vol 849 (2) ◽  
pp. 136 ◽  
Author(s):  
C. Tapia ◽  
S. Lizano
Keyword(s):  
Accretion Disks ◽  
Young Stars

Can complex T Tauri star light curves be modelled with star-spots?

2020 ◽  
Vol 500 (1) ◽  
pp. 1366-1379
Author(s):  
C Koen
Keyword(s):  
Ridge Regression ◽  
Young Stars ◽  
Light Curves ◽  
Stellar Surface ◽  
Tauri Star ◽  
T Tauri ◽  
Almost All

ABSTRACT ‘Transiting Exoplanet Survey Satellite’ photometry of 10 young stars with very complex periodic light curves is considered. Previous findings that these cannot be due to dark surface spots are re-evaluated by allowing arbitrarily shaped areas on the stellar surface to have sub-photospheric fluxes. This is done by approximating flux integrals by sums over surface elements. The unknown ratios of spot to photospheric fluxes are determined by lasso or ridge regression procedures. It is found that almost all light curves can be modelled very accurately in this way. The usual, if rarely stated, caveat applies – star-spot models presented in the paper are not unique.

scholarly journals Resolved Stellar Populations of the interacting galaxies of the M81 group

2016 ◽  
Vol 11 (S321) ◽  
pp. 22-24
Author(s):  
Sakurako Okamoto ◽  
Nobuo Arimoto ◽  
Annette M.N. Ferguson ◽  
Edouard J. Bernard ◽  
Mike J. Irwin ◽  
...  
Keyword(s):  
Main Sequence ◽  
Field Survey ◽  
State Of The Art ◽  
Young Stars ◽  
Interacting Galaxies ◽  
Wide Field ◽  
Red Giant ◽  
Tidal Streams ◽  
Stellar Associations ◽  
First Time

AbstractWe present the results from the state-of-the-art wide-field survey of the M81 galaxy group that we are conducting with Hyper Suprime-Cam on Subaru Telescope. Our photometry reaches about 2 mag below the tip of the red giant branch (RGB) and reveals the spatial distribution of both old and young stars over an area of 5°2around the M81. The young main-sequence (MS) stars closely follow the HI distribution and can be found in a stellar stream between M81 and NGC 3077 and in numerous outlying stellar associations. Our survey also reveals for the first time the very extended (>2 × R25) halos of RGB stars around M81, M82, and NGC 3077, as well as faint tidal streams that link these systems. The gravitational interactions between M81, M82 and NGC 3077 galaxies induced star formation in tidally stripped gas, and also significantly perturbed the older stellar components leading to disturbed halo morphologies.

scholarly journals Variability of young stars: Determination of rotational periods of weak-line T Tauri stars in the Cepheus-Cassiopeia star-forming region

2009 ◽  
Vol 330 (5) ◽  
pp. 482-492
Author(s):  
A. Koeltzsch ◽  
M. Mugrauer ◽  
St. Raetz ◽  
T.O.B. Schmidt ◽  
T. Roell ◽  
...  
Keyword(s):  
T Tauri Stars ◽  
Young Stars ◽  
Weak Line ◽  
Star Forming ◽  
T Tauri

scholarly journals Empirical isochrones and relative ages for young stars, and the radiative-convective gap

2007 ◽  
Vol 375 (4) ◽  
pp. 1220-1240 ◽  
Author(s):  
N. J. Mayne ◽  
Tim Naylor ◽  
S. P. Littlefair ◽  
Eric S. Saunders ◽  
R. D. Jeffries
Keyword(s):  
Young Stars

scholarly journals Hypersonic swizzle sticks: jets, fossil cavities and turbulence in molecular clouds

2006 ◽  
Vol 2 (S237) ◽  
pp. 172-176
Author(s):  
Andrew J Cunningham ◽  
Adam Frank ◽  
Eric G Blackman ◽  
Alice Quillen
Keyword(s):  
Turbulent Flows ◽  
Molecular Clouds ◽  
Turbulent Medium ◽  
Young Stars ◽  
Turbulence Energy ◽  
Theoretical Simulation ◽  
Bow Shocks ◽  
Ambient Gas ◽  
Energy And Momentum ◽  
Ability To Drive

AbstractThe ubiquity and high density of outflows from young stars in clusters make them an intriguing candidate for the source of turbulence energy in molecular clouds. In this contribution we discuss new studies, both observational and theoretical, which address the issue of jet/outflow interactions and their ability to drive turbulent flows in molecular clouds. Our results are surprising in that they show that fossil cavities, rather than bow shocks from active outflows, constitute the mechanism of re-energizing turbulence. We first present simulations which show that collisions between active jets are ineffective at converting directed momentum and energy in outflows into turbulence. This effect comes from the ability of radiative cooling to constrain the surface area through which colliding outflows entrain ambient gas. We next discuss observational results which demonstrate that fossil cavities from “extinct” outflows are abundant in molecular material surrounding clusters such as NGC 1333. These structures, rather than the bow shocks of active outflows, comprise the missing link between outflow energy input and re-energizing turbulence. In a separate theoretical/simulation study we confirm that the evolution of cavities from decaying outflow sources leads to structures which match the observations of fossil cavities. Finally we present new results of outflow propagation in a fully turbulent medium exploring the explicit mechanisms for the transfer of energy and momentum between the driving wind and the turbulent environment.

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