scholarly journals The Possible Connexion Between T Tauri Stars and UV Ceti Stars

1957 ◽  
Vol 3 ◽  
pp. 26-30 ◽  
Author(s):  
Guillermo Haro
Keyword(s):  
T Tauri Stars ◽  
The Sun ◽  
Late Type ◽  
Dwarf Stars ◽  
Present Discussion ◽  
T Tauri ◽  
Flare Stars ◽  
Periodic Changes

As is well known, very rapid and non-periodic changes in brightness have been discovered in several late-type dwarf stars in recent years. In the vicinity of the sun, within a radius not exceeding 10 parsecs, nine or ten such objects have been found and named ‘flare’ stars because of their extraordinarily rapid variations. The prototype of these flare stars is UV Ceti. For the purpose of the present discussion, we shall call these objects ‘classical’ flare stars.

scholarly journals T Tauri stars and flare stars: common properties and differences

1990 ◽  
Vol 137 ◽  
pp. 209-213
Author(s):  
I. Appenzeller
Keyword(s):  
Accretion Disks ◽  
T Tauri Stars ◽  
The Other ◽  
Late Type ◽  
Physical Origin ◽  
Other Hand ◽  
T Tauri ◽  
Low Mass ◽  
Flare Stars

T Tauri stars and flare stars are both magnetically active late-type stars of low mass and low to moderate luminosities. The flares observed in these two classes of variables show similar properties and, thus, probably have the same physical origin. On the other hand, at least the majority of the classical T Tauri stars seem to be surrounded by cool, dusty (accretion) disks, which are absent or undetectable in most classical flare stars.

scholarly journals X-ray Flare Rate of T Tauri Stars in Taurus

1995 ◽  
Vol 151 ◽  
pp. 216-217
Author(s):  
R. Neuhäuser ◽  
Th. Preibisch
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
T Tauri Stars ◽  
Medium Size ◽  
Late Type ◽  
Large Sample ◽  
X Ray ◽  
T Tauri ◽  
Sky Survey ◽  
Low Mass

AbstractWe study the X-ray emission of several hundred (young, low-mass, late-type, pre-main sequence) T Tauri stars (TTS) in the Taurus T association, a nearby well-studied region of ongoing star formation. We report on X-ray emission variability of TTS as observed with the flux-limited ROSAT All-Sky Survey (RASS). Since RASS observations are spatially unbiased, we can investigate the X-ray flare rate of TTS on a large sample. We find that large flares are very rare (once per year), while medium-size flares can occur once in ∼ 40 days.

Observations of Flare Stars and T Tauri Stars

1967 ◽  
Vol 1 (1) ◽  
pp. 15-15 ◽  
Author(s):  
Arthur A. Page
Keyword(s):  
United Kingdom ◽  
New Zealand ◽  
Variable Stars ◽  
T Tauri Stars ◽  
Schmidt Telescope ◽  
The United Kingdom ◽  
T Tauri ◽  
Flare Stars ◽  
Photographic Photometry

Photographic observations of Flare Stars in association with Slee, Higgins and Patston, T Association patrols, photographic photometry of selected variable stars in association with Bateson of New Zealand and surveillance of comets brighter than V = 13m, in association with Candy of the United Kingdom constitute the principal fields of research of Page Observatory (private), situated 7 miles North of Brisbane. A recently constructed f2.9 8in/12.5in Schmidt telescope now serves as the main photographic instrument.

scholarly journals Radio Emission from the Sun and Stars: New Insights into Energetic Phenomena

2004 ◽  
Vol 219 ◽  
pp. 145-158
Author(s):  
T. S. Bastian
Keyword(s):  
Radio Emission ◽  
Energy Release ◽  
Coronal Mass Ejections ◽  
Magnetic Energy ◽  
Spectroscopic Techniques ◽  
The Sun ◽  
Late Type ◽  
Radio Observations ◽  
Dwarf Stars ◽  
Magnetic Energy Release

Energetic phenomena on the Sun and late-type stars pose a number of fascinating puzzles. These include coronal heating, flares, and coronal mass ejections, all believed to be manifestations of magnetic energy release. Radio radiation is a sensitive tracer of energetic phenomena on both the Sun and stars. Radio observations of the Sun over the past decade have produced new insights into the physics of magnetic energy release in flares and coronal mass ejections. Radio observations of late-type stars have exploited sensitive imaging and spectroscopic techniques to further constrain the nature of the relevant emission mechanisms. A surprise has been the recent discovery of radio emission from brown dwarf stars, implying the existence of substantial magnetic fields and a means of dissipating magnetic energy, neither of which are understood.

scholarly journals New nearby young star cluster candidates within 200 pc

2006 ◽  
Vol 2 (S237) ◽  
pp. 442-442 ◽  
Author(s):  
Eric E. Mamajek
Keyword(s):  
Young Star ◽  
Star Cluster ◽  
T Tauri Stars ◽  
The Sun ◽  
Visual Extinction ◽  
T Tauri ◽  
Space Motion ◽  
Group D

AbstractI briefly describe two new young star cluster candidates found within 200 pc of the Sun, associated with the 4th-magnitude stars μ Oph and 32 Ori. The μ Oph group (d ≃ 170pc) has a space motion and age (~120± 25 Myr) suspiciously similar to the Pleiades, but lies in the opposite side of the sky behind ~0.9 mag of visual extinction in Ophiuchus. The 32 Ori group is a nearby (d ≃ 90 pc) loose aggregate of ~25-Myr-old post-T Tauri stars co-moving with the massive binary 32 Ori (B5V+B7V) in northern Orion. The 32 Ori group accounts for part of the population of “isolated” Li-rich RASS pre-MS stars in northern Orion.

scholarly journals A New Association of Post–T Tauri Stars near the Sun

2000 ◽  
Vol 120 (3) ◽  
pp. 1410-1425 ◽  
Author(s):  
Carlos A. O. Torres ◽  
Licio da Silva ◽  
Germano R. Quast ◽  
Ramiro de la Reza ◽  
Evgueni Jilinski
Keyword(s):  
T Tauri Stars ◽  
The Sun ◽  
T Tauri ◽  
New Association

scholarly journals Radio Evidence for Nonthermal Particle Acceleration on Stars of Late Spectral Type

1994 ◽  
Vol 142 ◽  
pp. 753-764
Author(s):  
Kenneth R. Lang
Keyword(s):  
Particle Acceleration ◽  
Radio Emission ◽  
Binary Stars ◽  
Main Sequence ◽  
Late Type ◽  
T Tauri ◽  
Rs Cvn Stars ◽  
Vlbi Data ◽  
Flare Stars ◽  
M Stars

AbstractRadio evidence for nonthermal particle acceleration on stars of late spectral type (G, K, and M) is reviewed, including the pre-main-sequence T Tauri stars, the dwarf M flare stars, and the RS CVn binary stars. Both the long-lasting radio emission and the transient radio flares can be attributed to nonthermal electrons accelerated in magnetically confined coronae, radiating by either incoherent gyrosynchrotron radiation or by coherent processes. Related observations of the Sun provide the framework for interpreting the radio emission of late-type stars. We review recent VLBI observations of single and binary stars, observations of rapid acceleration and dynamic spectra of dwarf M flare stars, and models for long-lasting radio emission from dwarf M flare stars and RS CVn stars. The VLBI data provide evidence for nonthermal particle acceleration in large-scale magneto-spheres several times larger than the stellar radius for T Tauri and RS CVn stars. In contrast, rapid radio flares on dwarf M stars require sources much smaller than the visible star in size, and this is consistent with the VLBI data.Dynamic spectra suggest particle acceleration by relativistic electron beams on dwarf M stars. The long-lived radio radiation of dwarf M stars and RS CVn stars requires more-or-less continuous particle acceleration over periods of hours, perhaps by persistent low-amplitude flaring.Subject headings: acceleration of particles — binaries: close — radio continuum: stars — stars: flare — stars: late-type — stars: pre-main-sequence

scholarly journals Some resolutions on T Tauri stars

1990 ◽  
Vol 137 ◽  
pp. 163-167
Author(s):  
V.A. Ambartsumian
Keyword(s):  
Detailed Analysis ◽  
Observational Data ◽  
T Tauri Stars ◽  
Young Stars ◽  
Simple Fact ◽  
T Tauri ◽  
Flare Stars

This symposium is dedicated to the results of studies of flare stars. The necessity of the detailed analysis of observational data on flare stars follows from the very simple fact, that until now the theory has not found for the answer to the question: why the young stars of low luminosity are flaring.

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