scholarly journals Observational diagnostics of elongated planet-induced vortices with realistic planet formation time-scales

2018 ◽  
Vol 482 (3) ◽  
pp. 3609-3621 ◽  
Author(s):  
Michael Hammer ◽  
Paola Pinilla ◽  
Kaitlin M Kratter ◽  
Min-Kai Lin
Keyword(s):  
Time Scales ◽  
Planet Formation ◽  
Formation Time

scholarly journals New Low-mass Accretors in the Scorpius-Centaurus OB Association

2015 ◽  
Vol 10 (S314) ◽  
pp. 58-62
Author(s):  
Simon J. Murphy ◽  
Warrick A. Lawson ◽  
Joao Bento
Keyword(s):  
Time Scales ◽  
Planet Formation ◽  
Formation Time ◽  
Lower Mass ◽  
Circumstellar Material ◽  
Hα Emission ◽  
Low Mass

AbstractWe describe the serendipitous discovery of two new lithium-rich M5 members of the Scorpius-Centaurus OB Association (Sco-Cen). Both stars exhibit large 12 and 22 μm excesses and strong, variable Hα emission which we attribute to accretion from circumstellar discs. Such stars are thought to be incredibly rare at the ~16 Myr median age of much of Sco-Cen. The serendipitous discovery of two accreting stars hosting large quantities of circumstellar material may be indicative of a sizeable age spread in Sco-Cen, or further evidence that disc dispersal and planet formation time-scales are longer around lower-mass stars.

scholarly journals Pre-main-sequence isochrones – II. Revising star and planet formation time-scales

2013 ◽  
Vol 434 (1) ◽  
pp. 806-831 ◽  
Author(s):  
Cameron P. M. Bell ◽  
Tim Naylor ◽  
N. J. Mayne ◽  
R. D. Jeffries ◽  
S. P. Littlefair
Keyword(s):  
Time Scales ◽  
Main Sequence ◽  
Planet Formation ◽  
Formation Time

scholarly journals Photometric Studies of the Extreme SMC Wing

1980 ◽  
Vol 85 ◽  
pp. 353-355 ◽  
Author(s):  
William E. Kunkel
Keyword(s):  
Star Formation ◽  
Time Scales ◽  
Formation Time ◽  
Stellar Systems ◽  
Tidal Disruption ◽  
Tidal Interaction ◽  
Magellanic Stream

Among the currently interesting problems of interpreting the Magellanic Stream as an instance of tidal disruption is that of finding some demonstrable phenomenon in the makeup of the involved material that parallels the better known cases of tidal interaction, as for example NGC4038/39, where the dynamic and star-formation time scales are in agreement (Schweizer 1977). The observational problems that beset the interpretation of the Magellanic Stream are numerous (Mathewson and Schwartz 1976, Kunkel 1979, Bregman 1979), and the marked difference between the composition of the Stream (evidenced purely through HI) and the stellar systems (at least 80 percent stars) is among the outstanding dilemmas remaining. Finding some counterpart in the Magellanic scene comparable to the better recognized instances of tidal interaction may go some way towards clarifying a perplexing situation.

scholarly journals Dancing to changa: a self-consistent prediction for close SMBH pair formation time-scales following galaxy mergers

2018 ◽  
Vol 475 (4) ◽  
pp. 4967-4977 ◽  
Author(s):  
M Tremmel ◽  
F Governato ◽  
M Volonteri ◽  
T R Quinn ◽  
A Pontzen
Keyword(s):  
Time Scales ◽  
Pair Formation ◽  
Formation Time ◽  
Galaxy Mergers ◽  
Self Consistent

scholarly journals The noble gas isotope record of hydrocarbon field formation time scales

2017 ◽  
Vol 471 ◽  
pp. 141-152 ◽  
Author(s):  
Igor N. Tolstikhin ◽  
Chris J. Ballentine ◽  
Boris G. Polyak ◽  
Edward M. Prasolov ◽  
Olga E. Kikvadze
Keyword(s):  
Time Scales ◽  
Noble Gas ◽  
Formation Time ◽  
Isotope Record ◽  
Noble Gas Isotope ◽  
Field Formation ◽  
Hydrocarbon Field

scholarly journals Pebble accretion in self-gravitating protostellar discs

2019 ◽  
Vol 485 (4) ◽  
pp. 4465-4473
Author(s):  
D H Forgan
Keyword(s):  
Time Scales ◽  
Planet Formation ◽  
Density Ratio ◽  
Streaming Instability ◽  
Planetary Cores ◽  
Low Mass ◽  
Spiral Structures ◽  
Protostellar Discs ◽  
Core Accretion ◽  
Solid Bodies

Abstract Pebble accretion has become a popular component to core accretion models of planet formation, and is especially relevant to the formation of compact, resonant terrestrial planetary systems. Pebbles initially form in the inner protoplanetary disc, sweeping outwards in a radially expanding front, potentially forming planetesimals and planetary cores via migration and the streaming instability. This pebble front appears at early times, in what is typically assumed to be a low-mass disc. We argue this picture is in conflict with the reality of young circumstellar discs, which are massive and self-gravitating. We apply standard pebble accretion and streaming instability formulae to self-gravitating protostellar disc models. Fragments will open a gap in the pebble disc, but they will likely fail to open a gap in the gas, and continue rapid inward migration. If this does not strongly perturb the pebble disc, our results show that disc fragments will accrete pebbles efficiently. We find that in general the pebble-to-gas-density ratio fails to exceed 0.01, suggesting that the streaming instability will struggle to operate. It may be possible to activate the instability if 10 cm grains are available, and spiral structures can effectively concentrate them in regions of low gravito-turbulence. If this occurs, lunar mass cores might be assembled on time-scales of a few thousand years, but this is likely to be rare, and is far from proven. In any case, this work highlights the need for study of how self-gravitating protostellar discs define the distribution and properties of solid bodies, for future planet formation by core accretion.

scholarly journals Formation time-scales for high-mass X-ray binaries in M33

2018 ◽  
Vol 479 (3) ◽  
pp. 3526-3544 ◽  
Author(s):  
Kristen Garofali ◽  
Benjamin F Williams ◽  
Tristan Hillis ◽  
Karoline M Gilbert ◽  
Andrew E Dolphin ◽  
...  
Keyword(s):  
Time Scales ◽  
Formation Time ◽  
High Mass ◽  
X Ray ◽  
X Ray Binaries

scholarly journals Solvent-tuning the collapse and helix formation time scales of λ6-85*

2006 ◽  
Vol 15 (11) ◽  
pp. 2596-2604 ◽  
Author(s):  
Charles Dumont ◽  
Yoshitaka Matsumura ◽  
Seung Joong Kim ◽  
Jinsong Li ◽  
Elena Kondrashkina ◽  
...  
Keyword(s):  
Time Scales ◽  
Formation Time ◽  
Helix Formation

scholarly journals Mapping collinear in-medium parton splittings

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Fabio Domínguez ◽  
José Guilherme Milhano ◽  
Carlos A. Salgado ◽  
Konrad Tywoniuk ◽  
Víctor Vila
Keyword(s):  
Phase Space ◽  
Radiation Pattern ◽  
Time Scales ◽  
Transport Coefficient ◽  
Formation Time ◽  
Close Correspondence ◽  
Classical Description ◽  
Theoretical Support

AbstractWe map the spectrum of $$1\rightarrow 2$$1→2 parton splittings inside a medium characterized by a transport coefficient $${\hat{q}}$$q^ onto the kinematical Lund plane, taking into account the finite formation time of the process. We discuss the distinct regimes arising in this map for in-medium splittings, pointing out the close correspondence to a semi-classical description in the limit of hard, collinear radiation with short formation times. Although we disregard any modifications of the original parton kinematics in course of the propagation through the medium, subtle modifications to the radiation pattern compared to the vacuum baseline can be traced back to the physics of color decoherence and accumulated interactions in the medium. We provide theoretical support to vacuum-like emissions inside the medium by delimiting the regions of phase space where it is dominant, identifying also the relevant time-scales involved. The observed modifications are shown to be quite general for any dipole created in the medium.

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