Dispersed T Tauri stars and galactic star formation

Research output: Contribution to journalArticle

111 Citations (Scopus)

Abstract

Existing samples of low-mass T Tauri stars from nearby star forming regions are very deficient in stars older than 2 Myr. We argue that this arises from the dispersal of stars outside well-surveyed regions and is not due to a burst of star formation, erroneous theoretical isochrones, or survey flux limits. Evidence is accumulating, most dramatically from the ROSAT All-Sky Survey, that a large population of weak-lined T Tauri (WTT) stars is widely dispersed within and around star forming complexes. The spatial distribution, age distribution, and kinematics of T Tauri stars, both close to and widely distributed around active clouds, are studied using simple models of T Tauri dispersal. Models are compared to observations of the Chamaeleon and Taurus-Auriga cloud complexes. The dispersal of T Tauri stars appears to have two major causes: slow isotropic drifting of stars away from long-lived star forming clouds, and star formation in short-lived rapidly moving cloudlets. The first mechanism is determined by the Δν ≃ 1 km s-1 thermal velocity dispersion of gas within molecular cloud cores. The second mechanism is determined by the large-scale turbulent motions of molecular cloud complexes. A third mechanism for dispersal, dynamical ejection of high-velocity T Tauri stars, appears to be less important. The results have a number of implications for star formation in the Galaxy: star formation in at least one cloud (Chamaeleon I) has been continuous for ≃20 Myr; star formation efficiencies of clouds may often be 20% or higher; a large fraction of low-mass stars may form in small short-lived cloudlets each producing no more than a few stars; and T Tauri kinematics support molecular evidence for large-scale turbulence in molecular clouds.

Original languageEnglish (US)
Pages (from-to)306-322
Number of pages17
JournalAstrophysical Journal
Volume468
Issue number1 PART I
DOIs
StatePublished - Jan 1 1996

Fingerprint

T Tauri stars
star formation
stars
molecular clouds
kinematics
age structure
turbulence
spatial distribution
ejection
bursts
gas
galaxies
causes
gases

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{5085f663f68d457ba2a33642003c547b,
title = "Dispersed T Tauri stars and galactic star formation",
abstract = "Existing samples of low-mass T Tauri stars from nearby star forming regions are very deficient in stars older than 2 Myr. We argue that this arises from the dispersal of stars outside well-surveyed regions and is not due to a burst of star formation, erroneous theoretical isochrones, or survey flux limits. Evidence is accumulating, most dramatically from the ROSAT All-Sky Survey, that a large population of weak-lined T Tauri (WTT) stars is widely dispersed within and around star forming complexes. The spatial distribution, age distribution, and kinematics of T Tauri stars, both close to and widely distributed around active clouds, are studied using simple models of T Tauri dispersal. Models are compared to observations of the Chamaeleon and Taurus-Auriga cloud complexes. The dispersal of T Tauri stars appears to have two major causes: slow isotropic drifting of stars away from long-lived star forming clouds, and star formation in short-lived rapidly moving cloudlets. The first mechanism is determined by the Δν ≃ 1 km s-1 thermal velocity dispersion of gas within molecular cloud cores. The second mechanism is determined by the large-scale turbulent motions of molecular cloud complexes. A third mechanism for dispersal, dynamical ejection of high-velocity T Tauri stars, appears to be less important. The results have a number of implications for star formation in the Galaxy: star formation in at least one cloud (Chamaeleon I) has been continuous for ≃20 Myr; star formation efficiencies of clouds may often be 20{\%} or higher; a large fraction of low-mass stars may form in small short-lived cloudlets each producing no more than a few stars; and T Tauri kinematics support molecular evidence for large-scale turbulence in molecular clouds.",
author = "Eric Feigelson",
year = "1996",
month = "1",
day = "1",
doi = "10.1086/177691",
language = "English (US)",
volume = "468",
pages = "306--322",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1 PART I",

}

Dispersed T Tauri stars and galactic star formation. / Feigelson, Eric.

In: Astrophysical Journal, Vol. 468, No. 1 PART I, 01.01.1996, p. 306-322.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Dispersed T Tauri stars and galactic star formation

AU - Feigelson, Eric

PY - 1996/1/1

Y1 - 1996/1/1

N2 - Existing samples of low-mass T Tauri stars from nearby star forming regions are very deficient in stars older than 2 Myr. We argue that this arises from the dispersal of stars outside well-surveyed regions and is not due to a burst of star formation, erroneous theoretical isochrones, or survey flux limits. Evidence is accumulating, most dramatically from the ROSAT All-Sky Survey, that a large population of weak-lined T Tauri (WTT) stars is widely dispersed within and around star forming complexes. The spatial distribution, age distribution, and kinematics of T Tauri stars, both close to and widely distributed around active clouds, are studied using simple models of T Tauri dispersal. Models are compared to observations of the Chamaeleon and Taurus-Auriga cloud complexes. The dispersal of T Tauri stars appears to have two major causes: slow isotropic drifting of stars away from long-lived star forming clouds, and star formation in short-lived rapidly moving cloudlets. The first mechanism is determined by the Δν ≃ 1 km s-1 thermal velocity dispersion of gas within molecular cloud cores. The second mechanism is determined by the large-scale turbulent motions of molecular cloud complexes. A third mechanism for dispersal, dynamical ejection of high-velocity T Tauri stars, appears to be less important. The results have a number of implications for star formation in the Galaxy: star formation in at least one cloud (Chamaeleon I) has been continuous for ≃20 Myr; star formation efficiencies of clouds may often be 20% or higher; a large fraction of low-mass stars may form in small short-lived cloudlets each producing no more than a few stars; and T Tauri kinematics support molecular evidence for large-scale turbulence in molecular clouds.

AB - Existing samples of low-mass T Tauri stars from nearby star forming regions are very deficient in stars older than 2 Myr. We argue that this arises from the dispersal of stars outside well-surveyed regions and is not due to a burst of star formation, erroneous theoretical isochrones, or survey flux limits. Evidence is accumulating, most dramatically from the ROSAT All-Sky Survey, that a large population of weak-lined T Tauri (WTT) stars is widely dispersed within and around star forming complexes. The spatial distribution, age distribution, and kinematics of T Tauri stars, both close to and widely distributed around active clouds, are studied using simple models of T Tauri dispersal. Models are compared to observations of the Chamaeleon and Taurus-Auriga cloud complexes. The dispersal of T Tauri stars appears to have two major causes: slow isotropic drifting of stars away from long-lived star forming clouds, and star formation in short-lived rapidly moving cloudlets. The first mechanism is determined by the Δν ≃ 1 km s-1 thermal velocity dispersion of gas within molecular cloud cores. The second mechanism is determined by the large-scale turbulent motions of molecular cloud complexes. A third mechanism for dispersal, dynamical ejection of high-velocity T Tauri stars, appears to be less important. The results have a number of implications for star formation in the Galaxy: star formation in at least one cloud (Chamaeleon I) has been continuous for ≃20 Myr; star formation efficiencies of clouds may often be 20% or higher; a large fraction of low-mass stars may form in small short-lived cloudlets each producing no more than a few stars; and T Tauri kinematics support molecular evidence for large-scale turbulence in molecular clouds.

UR - http://www.scopus.com/inward/record.url?scp=33749176948&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749176948&partnerID=8YFLogxK

U2 - 10.1086/177691

DO - 10.1086/177691

M3 - Article

AN - SCOPUS:33749176948

VL - 468

SP - 306

EP - 322

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART I

ER -