Disk Accretion Rates for T Tauri Stars

Gullbring, E.; Hartmann, L.; Briceño, César; Calvet, Nuria

doi:10.1086/305032

Cited by 876 publications

(1,199 citation statements)

References 35 publications

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“…The result is an excess of ultra-violet (UV) energy which is detectable in addition to the regular photospheric emission. This phenomenon has been observed in numerous CTTs to date Gullbring et al 1998Gullbring et al , 2000Ingleby et al 2013), and has been shown to be present in HAeBes (Garrison 1978;Muzerolle et al 2004; Donehew & Brittain 2011;Mendigutía et al 2011Mendigutía et al , 2013Fairlamb et al 2015). Provided the stellar parameters are known, the accretion luminosity can be straight-forwardly converted into a mass accretion rate,Ṁacc, one of the key astrophysical parameters in star formation.…”

Section: Introductionmentioning

confidence: 83%

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Fairlamb

Oudmaijer

Mendigutía

et al. 2016

Mon. Not. R. Astron. Soc.

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The Herbig Ae/Be stars (HAeBes) allow an exploration of the properties of PreMain Sequence(PMS) stars above the low-mass range (< 2 M ⊙ ) and those bordering the high-mass range (> 8 M ⊙ ). This paper is the second in a series exploring accretion in 91 HAeBes with Very Large Telescope/X-shooter spectra. Equivalent width measurements are carried out on 32 different lines, spanning the UV to NIR, in order to obtain their line luminosities. The line luminosities were compared to accretion luminosities, which were determined directly from measurements of an UV-excess. When detected, emission lines always demonstrate a correlation with the accretion luminosity, regardless of detection frequency. The average relationship between accretion luminosity and line luminosity is found to be L acc ∝ L line 1.16±0.15 . This is in agreement with the findings in Classical T Tauri stars, although the HAeBe relationship is generally steeper, particularly towards the Herbig Be mass range. Since all observed lines display a correlation with the accretion luminosity, all of them can be used as accretion tracers. This has increased the number of accretion diagnostic lines in HAeBes tenfold. However, questions still remain on the physical origin of each line, which may not be due to accretion.

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Section: Introductionmentioning

confidence: 83%

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Fairlamb

Oudmaijer

Mendigutía

et al. 2016

Mon. Not. R. Astron. Soc.

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“…These strong stellar magnetic fields are believed to significantly alter the accretion flow in the circumstellar disk close to the central star. Based on models originally developped for magnetized compact objects in cataclysmic binaries (Ghosh & Lamb 1979) and assuming that T Tauri magnetospheres are predominantly dipolar on the large scale, Camenzind (1990) and Königl (1991) showed that the inner accretion disk is expected to be truncated by the magnetosphere at a distance of a few stellar radii above the stellar surface for typical mass accretion rates of 10 −9 to 10 −7 M ⊙ yr −1 in the disk (Basri & Bertout 1989;Hartigan et al 1995;Gullbring et al 1998). Disk material is then channeled from the disk inner edge onto the star along the magnetic field lines, thus giving rise to magnetospheric accretion columns.…”

Section: Introductionmentioning

confidence: 99%

Magnetically Channeled Accretion in T Tauri Stars

Bouvier¹,

Alencar

Dougados³

2003

Open Issues in Local Star Formation

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“…A mass accretion rate of ∼3.0 × 10 −7 M yr −1 is inferred from the observed L acc , following the expressioṅ M acc = (L acc R * /G M * ) × (1 − R * /R i ), R i being the inner radius of the accretion disk (with R i = 5 R * , see Gullbring et al 1998). The derived value is higher than those found in more evolved objects of roughly the same mass Gatti et al 2006), again pointing to the young nature of this source.…”

Section: Accretion and Ejection Propertiesmentioning

confidence: 99%

Spatially resolved H₂emission from a very low-mass star

Lopez

Garatti

Weigelt

et al. 2013

A&A

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Context. Molecular outflows from very low-mass stars (VLMSs) and brown dwarfs have been studied very little. So far, only a few CO outflows have been observed, allowing us to map the immediate circumstellar environment. Aims. We present the first spatially resolved H 2 emission around IRS54 (YLW 52), a ∼0.1-0.2 M Class I source. Methods. By means of VLT SINFONI K-band observations, we probed the H 2 emission down to the first ∼50 AU from the source.Results. The molecular emission shows a complex structure delineating a large outflow cavity and an asymmetric molecular jet. Thanks to the detection of several H 2 transitions, we are able to estimate average values along the jet-like structure (from source position to knot D) of A V ∼ 28 mag, T ∼ 2000−3000 K, and H 2 column density N(H 2 ) ∼ 1.7 × 10 17 cm −2 . This allows us to estimate a mass loss rate of ∼2 × 10 −10 M yr −1 for the warm H 2 component. In addition, from the total flux of the Br γ line, we infer an accretion luminosity and mass accretion rate of 0.64 L and ∼3 × 10 −7 M yr −1 , respectively. The outflow structure is similar to those found in low-mass Class I and CTTS. However, the L acc /L bol ratio is very high (∼80%), and the mass accretion rate is about one order of magnitude higher when compared to objects of roughly the same mass, pointing to the young nature of the investigated source.

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Disk Accretion Rates for T Tauri Stars

Cited by 876 publications

References 35 publications

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Magnetically Channeled Accretion in T Tauri Stars

Spatially resolved H₂emission from a very low-mass star

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Disk Accretion Rates for T Tauri Stars

Cited by 876 publications

References 35 publications

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

A spectroscopic survey of Herbig Ae/Be stars with X-Shooter – II. Accretion diagnostic lines

Magnetically Channeled Accretion in T Tauri Stars

Spatially resolved H2emission from a very low-mass star

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Product

Resources

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Spatially resolved H₂emission from a very low-mass star