A Hot Wind from the Classical T Tauri Stars: TW Hydrae and T Tauri

Dupree, A. K.; Brickhouse, N. S.; Smith, Graeme H.; Strader, Jay

doi:10.1086/431323

Cited by 91 publications

(161 citation statements)

References 36 publications

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“…loss rate, viz. 10 −12 to −11 ≤Ṁ loss < 7 × 10 −10 M yr −1 (Dupree et al 2005;Lamzin et al 2004, respectively), and with an age of about 10 Myr (de la Reza et al 2006), it is likely also the oldest. Herczeg et al (2004) report the detection of Lα-excited H 2 , with an N(H 2 ) = 3 × 10 18 cm −2 , which appears accurate to within an order of magnitude.…”

Section: Tw Hyamentioning

confidence: 98%

Odin observations of water in molecular outflows and shocks

Bjerkeli¹,

Liseau²,

Olberg

et al. 2009

A&A

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Aims. We investigate the ortho-water abundance in outflows and shocks in order to improve our knowledge of shock chemistry and of the physics behind molecular outflows. Methods. We used the Odin space observatory to observe the H 2 O(1 10 −1 01 ) line. We obtain strip maps and single pointings of 13 outflows and two supernova remnants where we report detections for eight sources. We used RADEX to compute the beam averaged abundances of o-H 2 O relative to H 2 . In the case of non-detection, we derive upper limits on the abundance. Results. Observations of CO emission from the literature show that the volume density of H 2 can vary to a large extent, a parameter that puts severe uncertainties on the derived abundances. Our analysis shows a wide range of abundances reflecting the degree to which shock chemistry affects the formation and destruction of water. We also compare our results with recent results from the SWAS team. Conclusions. Elevated abundances of ortho-water are found in several sources. The abundance reaches values as high as what would be expected from a theoretical C-type shock where all oxygen, not in the form of CO, is converted to water. However, the high abundances we derive could also be due to the low densities (derived from CO observations) that we assume. The water emission may in reality stem from high density regions much smaller than the Odin beam. We do not find any relationship between the abundance and the mass loss rate. On the other hand, there is a relation between the derived water abundance and the observed maximum outflow velocity.

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Section: Tw Hyamentioning

confidence: 98%

Odin observations of water in molecular outflows and shocks

Bjerkeli¹,

Liseau²,

Olberg

et al. 2009

A&A

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“…In most T Tauri sources, the line is primarily observed in absorption and sometimes exhibits a P Cygni profile. Dupree et al (2005) observed the He i 1.0830 m absorption line toward classical T Tauri stars TW Hya and T Tau. Both objects exhibit a strong P Cygni profile and the spectra are interpreted to indicate the presence of hot winds.…”

Section: He Imentioning

confidence: 98%

Post‐Outburst Infrared Spectra of V1647 Ori, the Illuminating Star of McNeil’s Nebula

Gibb¹,

Rettig²,

Brittain³

et al. 2006

ApJ

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V1647 Ori is a low-mass star in the L1630 star-forming region that underwent an outburst in late 2003 and early 2004. We present postoutburst infrared spectra obtained with NIRSPEC (Keck II ) and SpeX ( IRTF) and compare these to spectra taken during the outburst. The results show that the temperature of the hot CO formed in the inner part of the disk has declined by $800 K, while the water and CO ice and low-J CO gas features remained unchanged, consistent with previous assertions that the latter, low-temperature features arise in the foreground cloud. The P Cygni profiles of the Paschen series that were present in the outburst spectra taken in 2004 March disappeared by late 2004. The equivalent width of the helium absorption line at 1.0830 m decreased from 8.9 to 3.9 8 between 2004 March and November, evidence that the hot, fast wind has decreased substantially. We discuss the implications for categorizing V1647 Ori among the known classes of outbursting young stars.

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“…Our analytically derived mass loss rates range from ∼10 −11 −10 −9 M ⊙ yr −1 (when taking into account the error on the stellar flare frequency power law slope). For comparison, TTS wind mass loss rates have been derived from various line diagnostics: for TW Hya, Dupree et al (2005) reportṀ O VII /φ = 2.3×10 −11 M ⊙ yr −1 andṀ C III /φ = 1.3×10 −12 M ⊙ yr −1 , where φ is the fractional stellar surface area from which the wind originates (e.g., a more collimated, polar wind will have φ 0.3). These outflow rates are less than the Hα emission derived accretion rate for TW Hya of 4×10 −10 M ⊙ yr −1 (Muzerolle et al 2000).…”

Section: Analytically Determined Tts Cme Mass-loss Ratesmentioning

confidence: 99%

Mass Loss in Pre-Main-Sequence Stars via Coronal Mass Ejections and Implications for Angular Momentum Loss

Aarnio

Matt

Stassun

2012

ApJ

111

142

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We develop an empirical model to estimate mass-loss rates via coronal mass ejections (CMEs) for solar-type pre-main-sequence (PMS) stars. Our method estimates the CME mass-loss rate from the observed energies of PMS X-ray flares, using our empirically determined relationship between solar X-ray flare energy and CME mass: log(M CME [g]) = 0.63 × log(E flare [erg]) − 2.57. Using masses determined for the largest flaring magnetic structures observed on PMS stars, we suggest that this solar-calibrated relationship may hold over 10 orders of magnitude in flare energy and 7 orders of magnitude in CME mass. The total CME mass-loss rate we calculate for typical solar-type PMS stars is in the range 10 −12 -10 −9 M ⊙ yr −1 . We then use these CME mass-loss rate estimates to infer the attendant angular momentum loss leading up to the main sequence. Assuming the CME outflow rate for a typical ∼1 M ⊙ T Tauri star is < 10 −10 M ⊙ yr −1 , the resulting spin-down torque is too small during the first ∼1 Myr to counteract the stellar spin-up due to contraction and accretion. However, if the CME mass-loss rate is 10 −10 M ⊙ yr −1 , as permitted by our calculations, the CME spin-down torque may influence the stellar spin evolution after an age of a few Myr.

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A Hot Wind from the Classical T Tauri Stars: TW Hydrae and T Tauri

Cited by 91 publications

References 36 publications

Odin observations of water in molecular outflows and shocks

Odin observations of water in molecular outflows and shocks

Post‐Outburst Infrared Spectra of V1647 Ori, the Illuminating Star of McNeil’s Nebula

Mass Loss in Pre-Main-Sequence Stars via Coronal Mass Ejections and Implications for Angular Momentum Loss

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