scholarly journals SpS1-Spectroscopic observations of young disk evolution with Herschel and ALMA

2009 ◽  
Vol 5 (H15) ◽  
pp. 522-523
Author(s):  
W. R. F. Dent
Keyword(s):  
Embedded Systems ◽  
Main Sequence ◽  
Protoplanetary Disks ◽  
T Tauri Stars ◽  
Planetary Formation ◽  
Spectroscopic Observations ◽  
T Tauri ◽  
Disk Evolution ◽  
Low Mass

In the next few years, both Herschel and ALMA will be providing unique new insights into the physics and chemistry of protoplanetary disks. In particular, they will be used to study how disks evolve from massive embedded systems around young Class 0 objects, through low-mass disks around optically-visible T Tauri stars, to debris disks around stars on the main-sequence. Gas dominates the mass in the younger systems, but in debris systems there is very little - if any. How does the gas disappear, what is the effect of this on planetary formation, and what is the role of “transition” disks? I outline some of the areas where these two large facilities will contribute to these studies, focussing on the Herschel Key project, GASPS, and looking forward to the role of ALMA.

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.

scholarly journals Non thermal emission from T Tauri stars

2010 ◽  
Vol 6 (S275) ◽  
pp. 404-405
Author(s):  
María V. del Valle ◽  
Gustavo E. Romero
Keyword(s):  
Main Sequence ◽  
Thermal Emission ◽  
High Energy ◽  
Magnetic Activity ◽  
T Tauri Stars ◽  
Main Sequence Stars ◽  
High Energy Radiation ◽  
X Ray ◽  
T Tauri ◽  
Low Mass

AbstractT Tauri stars are low mass, pre-main sequence stars. These objects are surrounded by an accretion disk and present strong magnetic activity. T Tauri stars are copious emitters of X-ray emission which belong to powerful magnetic reconnection events. Strong magnetospheric shocks are likely outcome of massive reconnection. Such shocks can accelerate particles up to relativistic energies through Fermi mechanism. We present a model for the high-energy radiation produced in the environment of T Tauri stars. We aim at determining whether this emission is detectable. If so, the T Tauri stars should be very nearby.

Recent Photoelectric and Spectroscopic Observations of YY Orionis Stars

1979 ◽  
Vol 46 ◽  
pp. 519-520
Author(s):  
R. Mundt
Keyword(s):  
T Tauri Stars ◽  
Spectroscopic Evidence ◽  
Spectroscopic Observations ◽  
T Tauri ◽  
Hydrodynamic Evolution ◽  
Uv Excess ◽  
Low Mass

AbstractThe YY Orionis Stars are a subclass of the T Tauri stars, which have a particularly strong UV-excess and show spectroscopic evidence for infailing envelopes, like the occurrence of inverse P Cygni profiles. They have been interpreted as low mass protostars in the final stages of their hydrodynamic evolution (Walker 1972, Appenzeller and Wolf 1977, Wolf et al. 1977).

scholarly journals Circumstellar maher of young low-mass stars: Observations versus theory

1987 ◽  
Vol 122 ◽  
pp. 23-38 ◽  
Author(s):  
Claude Bertout
Keyword(s):  
T Tauri Stars ◽  
Young Stellar Objects ◽  
Low Mass Stars ◽  
Stellar Objects ◽  
Star Forming ◽  
T Tauri ◽  
Region I ◽  
Low Mass ◽  
Infrared Sources

After presenting NGC 7129 as a prototypical star-forming region, I discuss what can be learned from the radio spectra of embedded infrared sources. I then review available observational evidence for disks around young stellar objects, with emphasis on accretion disks around T Tauri stars. Finally, new results on the role of magnetic fields in the circumstellar activity of T Tauri stars are presented.

scholarly journals Evidences of protoplanetary disks in a selected sample of weak T Tauri stars

2004 ◽  
Vol 202 ◽  
pp. 335-337
Author(s):  
Jane Gregorio-Hetem ◽  
Annibal Hetem
Keyword(s):  
Main Sequence ◽  
Planetary System ◽  
Protoplanetary Disks ◽  
T Tauri Stars ◽  
Evolutionary Sequence ◽  
Main Sequence Stars ◽  
T Tauri ◽  
Dust Distribution

A model with two dust components is used do explain the circumstellar structure of weak-T Tauri stars. The IR-excess was calculated and compared to spectroscopic criteria in order to classify the objects according an evolutionary sequence. About 46% of the sample correspond to young main sequence stars showing dust distribution consistent with a disrupted disk, that could be possibly caused by the formation of a planetary system.

scholarly journals NMA Imaging of Envelopes and Disks around Low Mass Protostars and T Tauri Stars

1997 ◽  
Vol 182 ◽  
pp. 381-390
Author(s):  
Yoshimi Kitamura ◽  
Masao Saito ◽  
Ryohei Kawabe ◽  
Kazuyoshi Sunada
Keyword(s):  
Accretion Disks ◽  
Molecular Clouds ◽  
Protoplanetary Disks ◽  
Hierarchical Structures ◽  
T Tauri Stars ◽  
Mass Star ◽  
Low Mass Stars ◽  
Star Forming ◽  
T Tauri ◽  
Low Mass

We are intensively studying low mass star formation with the radio telescopes at Nobeyama in Japan. Using both the Nobeyama 45 m dish equipped with a 2 × 2 array receiver and the Nobeyama Millimeter Array (NMA), we can cover a very wide spatial range from overall molecular clouds down to compact protoplanetary disks. With the 45 m dish we are investigating hierarchical structures of molecular clouds including star-forming cores. With NMA we are imaging disklike structures (i.e., envelopes, accretion disks, and protoplanetary disks) around protostars and T Tauri stars. Recently, we have completed our survey for dense disklike envelopes around eleven Class 0 & I protostars by NMA. In this paper, we will present our recent results of the disklike envelopes in addition to the previous NMA results of the disks around three T Tauri stars. On the basis of the data, we will discuss the evolution of the disklike structures (dense envelopes → tenuous ones → dispersing ones → accretion disks → protoplanetary ones), and propose a new scenario for the formation of low mass stars.

scholarly journals Magnetic Activity of T Tauri Stars

1992 ◽  
Vol 9 ◽  
pp. 653-654
Author(s):  
T. Montmerle
Keyword(s):  
Solar Activity ◽  
Main Sequence ◽  
Magnetic Activity ◽  
T Tauri Stars ◽  
X Rays ◽  
General Review ◽  
Near Ir ◽  
T Tauri ◽  
Low Mass ◽  
Pms Stars

T Tauri stars (TTS) are low-mass (M ≲ 1M⊙) pre-main sequence (PMS) stars (for a general review, see Bertout 1989). They have long been known to be variable from near-TIV to near-IR wavelengths, on timescales ranging from a few minutes to a few decades. They are observed to flare in many wavenlength rages, from X-rays to the radio, and all the existing evidence is consistent with a very strong magnetic activity, in many ways analogous to solar activity (for a review, see, e.g., Montmerle et al. 1991).

scholarly journals The naked T Tauri stars: The low mass pre-main sequence unveiled

1987 ◽  
Vol 122 ◽  
pp. 107-108
Author(s):  
Frederick M. Walter
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
T Tauri Stars ◽  
Low Mass Stars ◽  
X Ray ◽  
T Tauri ◽  
Low Mass ◽  
The Impact ◽  
Circumstellar Environment

I discuss a survey of X-ray sources in regions of star formation. The survey has revealed at least 30 low mass PMS, naked T Tauri stars (NTTS) in Tau-Aur, and a comparable number in Oph. I summarize the properties of these stars, and argue that the spectra of the classical T Tauri stars are due to the interaction of an underlying NTTS with a dominant circumstellar environment. I discuss the impact the NTTS are likely to have on our understanding of the PMS evolution of low mass stars.

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