ESO-H<i>α</i>574 and Par-Lup 3-4 jets: Exploring the spectral, kinematical, and physical properties

Whelan, Emma; Bonito, R.; Antoniucci, S.; Alcalá, J. M.; Giannini, T.; Nisini, B.; Bacciotti, F.; Podio, L.; Stelzer, B.; Comerón, F.

doi:10.1051/0004-6361/201322037

Cited by 23 publications

(37 citation statements)

References 79 publications

(170 reference statements)

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“…For example, Herczeg & Hillenbrand (2008) found a correlation between the [O i] 6300 Å luminosity and the accretion luminosity in T Tauri stars. This relationship has been used to infer the mass accretion rates in embedded objects or in edge-on-disk T Tauri where the permitted line emission is partially hidden at a direct view (Whelan et al 2014;Riaz et al 2015). However, the [O i] emission in the Herczeg & Hillenbrand sample was dominated by the low velocity wind component.…”

Section: Mass Accretion Ratementioning

confidence: 99%

The small-scale HH34 IRS jet as seen by X-shooter

Nisini¹,

Giannini²,

Antoniucci³

et al. 2016

A&A

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Context. Atomic jets are a common phenomenon among young stars, being intimately related to disk accretion. Most studies have been performed on jets from pre-main sequence stars. However, to date very little detailed information has been gathered on jets from young embedded low mass sources (the so-called class I stars), especially in the inner jet region. Aims. We exploit a diagnostic analysis based on multiwave spectroscopic observations to infer kinematics and physical conditions of the inner region of the prototypical class I jet from HH34 IRS. Methods. We use a deep X-shooter spectrum covering the wavelength range 350−2300 nm at resolution between ∼8000 and ∼18 000 (i.e., ∆V ∼ 17−27 km s −1 ), which allows us to detect lines in a wide range of excitation conditions (from E up ∼ 8000 to ∼31 000 cm −1 ) and to study their kinematics. Statistical equilibrium and ionization models are adopted to derive the jet main physical parameters. Results. We separately derive the physical conditions for the extended high velocity jet (HVC, V r ∼ −100 km s −1 ) and for the low velocity and compact gas (LVC, V r ∼ −20−50 km s −1 ) located on-source. Close to the jet base (<200 AU from source) the HVC gas is mostly neutral (x e < 0.1) and very dense (n H > 5 × 10 5 cm −3 ). The LVC gas has the same density and A V as the HVC, but it is at least a factor of two colder. Iron abundance in the HVC is consistent with the solar value, while it is a factor of 3 subsolar in the LVC, suggesting an origin of the LVC gas from a dusty disk. From the derived total density we infer that the jet mass flux rate is >5 × 10 −7 M yr −1 . We find that the relationships between accretion luminosity and permitted line luminosity derived for T Tauri stars cannot be directly extended to class I sources embedded in reflection nebulae since the permitted lines are seen through scattered light. An accretion rate of ∼7 × 10 −6 M yr −1 is instead derived from an empirical relationship connectingṀ acc with L([O i])(HVC).Conclusions. The class I HH34 IRS jet at small scale shares many kinematical and physical properties with the jets from the most active classical T Tauri (CTT) stars. However, the HH34 IRS jet is denser as a consequence of the larger mass ejection rate with respect to typical values in CTTs jets. These findings suggests that the acceleration and excitation mechanisms in collimated jets are not influenced by evolution and are similar in CTTs and in still embedded sources with high accretion rates.

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Section: Mass Accretion Ratementioning

confidence: 99%

The small-scale HH34 IRS jet as seen by X-shooter

Nisini¹,

Giannini²,

Antoniucci³

et al. 2016

A&A

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“…Due to the moderate inclination of the disk (given in Sect. 2.1) L line did not need to be corrected for obscuration by the disk as in Whelan et al (2014a). Also included is the literature value taken from (Muzerolle et al 2005).…”

Section: Estimatingṁ Out /ṁ Accmentioning

confidence: 99%

“…The measurements ofṀ out are based on the following equations and further information can be found in Whelan et al (2014a).…”

Section: Estimatingṁ Out /ṁ Accmentioning

confidence: 99%

“…Magneto-centrifugal jet launching models place an upper limit (per jet) of ∼0.3 on this ratio (Ferreira et al 2006;Cabrit 2009). However, as discussed in Whelan et al (2009bWhelan et al ( , 2014a, observational biases had a strong influence on these first studies. How this ratio compares in BDs and low mass YSOs could tell us something very important about how BDs form.…”

Section: Introductionmentioning

confidence: 99%

“…4.2). This work is part of a larger study to investigate the accretion-ejection connection in BDs and very low mass stars (VLMSs; Whelan et al 2014a;Giannini et al 2013;Stelzer et al 2013). …”

Section: Introductionmentioning

confidence: 99%

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Accretion-ejection connection in the young brown dwarf candidate ISO-ChaI 217

Whelan

Alcalá

Bacciotti

et al. 2014

A&A

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As the number of observed brown dwarf outflows is growing it is important to investigate how these outflows compare to the wellstudied jets from young stellar objects. A key point of comparison is the relationship between outflow and accretion activity and in particular the ratio between the mass outflow and accretion rates (Ṁ out /Ṁ acc ). The brown dwarf candidate ISO-ChaI 217 was discovered by our group, as part of a spectro-astrometric study of brown dwarfs, to be driving an asymmetric outflow with the blueshifted lobe having a position angle of ∼20 • . The aim here is to further investigate the properties of ISO-ChaI 217, the morphology and kinematics of its outflow, and to better constrainṀ out /Ṁ acc . The outflow is spatially resolved in the [S ] λλ6716, 6731 lines and is detected out to ∼1. 6 in the blue-shifted lobe and 1 in the red-shifted lobe. The asymmetry between the two lobes is confirmed although the velocity asymmetry is less pronounced with respect to our previous study. Using thirteen different accretion tracers we measure log (Ṁ acc ) [M /yr] = −10.6 ± 0.4. As it was not possible to measure the effect of extinction on the ISO-ChaI 217 outflowṀ out was derived for a range of values of A v , up to a value of A v = 2.5 mag estimated for the source extinction. The logarithm of the mass outflow (Ṁ out ) was estimated in the range −11.7 to −11.1 for both jets combined. ThusṀ out /Ṁ acc [M /yr] lies below the maximum value predicted by magneto-centrifugal jet launching models. Finally, both model fitting of the Balmer decrements and spectro-astrometric analysis of the Hα line show that the bulk of the H I emission comes from the accretion flow.

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Jets from young stars and brown dwarfs

Whelan¹

2014

Astron Nachr

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The protostellar outflow mechanism operates for a significant fraction of the pre-main sequence phase of a solar mass star and is thought to have a key role in star and perhaps even planet formation. This energetic mechanism manifests itself in several different forms and on many scales. Thus outflow activity can be probed in numerous different regimes from radio to X-ray wavelengths. Recent discoveries have shown that it is not only solar mass stars that launch outflows during their formation but also the sub-stellar brown dwarfs. In this article what is currently known about jets from young stars is summarised, including an outline of why it is important to study jets. The second part of this article is dedicated to jets from young brown dwarfs. While only a small number of brown dwarf outflows have been investigated to date, interesting properties have been observed. Here observations of brown dwarf outflows are described and what is currently known of their properties compared to low mass protostellar outflows.

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ESO-Hα574 and Par-Lup 3-4 jets: Exploring the spectral, kinematical, and physical properties

Cited by 23 publications

References 79 publications

The small-scale HH34 IRS jet as seen by X-shooter

The small-scale HH34 IRS jet as seen by X-shooter

Accretion-ejection connection in the young brown dwarf candidate ISO-ChaI 217

Jets from young stars and brown dwarfs

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