An Asymmetric Outflow from the Herbig Ae Star HD 163296

Wassell, E. J.; Grady, C. A.; Woodgate, B. E.; Kimble, Randy A.; Bruhweiler, F. C.

doi:10.1086/507268

Cited by 50 publications

(104 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given that a bipolar microjet is known to be associated with HD 163296 (Wassell et al 2006), the question arises of whether the far-infrared molecular line emission presented here indeed arises from the disk or whether it comes from such a jet. There are several arguments in favor of the disk.…”

Section: Discussionmentioning

confidence: 99%

Warm H₂O and OH in the disk around the Herbig star HD 163296

Fedele

Bruderer

Dishoeck

et al. 2012

A&A

View full text Add to dashboard Cite

We present observations of far-infrared (50−200 μm) OH and H 2 O emission of the disk around the Herbig Ae star HD 163296 obtained with Herschel/PACS in the context of the DIGIT key program. In addition to strong [O i] emission, a number of OH doublets and a few weak highly excited lines of H 2 O are detected. The presence of warm H 2 O in this Herbig disk is confirmed by a line stacking analysis, enabled by the full PACS spectral scan, and by lines seen in Spitzer data. The line fluxes are analyzed using a local-thermal-equilibrium slab model including line opacity. The H 2 O column density is 10 14 −10 15 cm −2 , and the excitation temperature is 200−300 K, implying warm gas with a density n > 10 5 cm −3 . For OH, we find N mol of 10 14 −10 15 cm −2 and T ex ∼ 300−500 K. For both species, we find an emitting region of r ∼ 15−20 AU from the star. We argue that the molecular emission arises from the protoplanetary disk rather than the outflow. This far-infrared detection of both H 2 O and OH contrasts with near-and mid-infrared observations, which have generally found a lack of water in the inner disk around Herbig AeBe stars owing to the strong photodissociation of H 2 O. Given the similar column density and emitting region, OH and H 2 O emission seems to arise from an upper layer of the disk atmosphere of HD 163296, which probes a new reservoir of water. The slightly lower temperature of H 2 O compared to OH suggests a vertical stratification of the molecular gas with OH located higher and H 2 O deeper in the disk, consistent with thermo-chemical models.

show abstract

Section: Discussionmentioning

confidence: 99%

Warm H₂O and OH in the disk around the Herbig star HD 163296

Fedele

Bruderer

Dishoeck

et al. 2012

A&A

View full text Add to dashboard Cite

show abstract

“…This is the average measured half width at half maximum of the spatially resolved [S ] intensity profile in similar HH objects, which ranges from 75−300 AU (e.g. Mundt et al 1991;Reipurth et al 2000Reipurth et al , 2002Wassell et al 2006). The inclination is estimated at i = 17.8 can be assumed that all oxygen is neutral and sulphur is all singly ionized.…”

Section: Mass Outflow Ratementioning

confidence: 99%

The outflow history of two Herbig-Haro jets in RCW 36: HH 1042 and HH 1043

Ellerbroek

Podio

Kaper

et al. 2013

A&A

View full text Add to dashboard Cite

Jets around low-and intermediate-mass young stellar objects (YSOs) contain a fossil record of the recent accretion and outflow activity of their parent star-forming systems. We aim to understand whether the accretion/ejection process is similar across the entire stellar mass range of the parent YSOs. To this end we have obtained optical to near-infrared spectra of HH 1042 and HH 1043, two newly discovered jets in the massive star-forming region RCW 36, using X-shooter on the ESO Very Large Telescope. HH 1042 is associated with the intermediate-mass YSO 08576nr292. Over 90 emission lines are detected in the spectra of both targets. Highvelocity (up to 220 km s −1 ) blue-and redshifted emission from a bipolar flow is observed in typical shock tracers. Low-velocity emission from the background cloud is detected in nebular tracers, including lines from high ionization species. We applied combined optical and infrared spectral diagnostic tools in order to derive the physical conditions (density, temperature, and ionization) in the jets. The measured mass outflow rates areṀ jet ∼ 10 −7 M yr −1 . It is not possible to determine a reliable estimate for the accretion rate of the driving source of HH 1043 using optical tracers. We measure a high accretion rate for the driving source of HH 1042 (Ṁ acc ∼ 10 −6 M yr −1 ). For this system the ratioṀ jet /Ṁ acc ∼ 0.1, which is comparable to low-mass sources and consistent with models for magneto-centrifugal jet launching. The knotted structure and velocity spread in both jets are interpreted as fossil signatures of a variable outflow rate. While the mean velocities in both lobes of the jets are comparable, the variations in mass outflow rate and velocity in the two lobes are not symmetric. This asymmetry suggests that the launching mechanism on either side of the accretion disk is not synchronized. For the HH 1042 jet, we have constructed an interpretative physical model with a stochastic or periodic outflow rate and a description of a ballistic flow as its constituents. We have simulated the flow and the resulting emission in position−velocity space, which is then compared to the observed kinematic structure. The knotted structure and velocity spread can be reproduced qualitatively with the model. The results of the simulation indicate that the outflow velocity varies on timescales on the order of 100 yr.Key words. circumstellar matter -ISM: jets and outflows -ISM: individual objects: HH 1042 -stars: formation -ISM: individual objects: HH 1043 -Herbig-Haro objects IntroductionAstrophysical jets are a ubiquitous signature of accretion. When the magnetic field of the circumstellar disk is coupled to a jet, magnetic torques can remove a significant fraction of the system's angular momentum and mass through the jet, when charged particles are ejected. Jets exist in accreting systems on various scales, ranging from young stellar objects (YSOs) up to evolved binary systems and active galactic nuclei (AGNs). They are detected in emission lines at all wavelengths, from the ra...

show abstract

“…These epochs should then be viewed as the intervals during which the bright knots have formed in the jet, close to the driving source. (2000); (2) Grady et al (2000); (3) Wassell et al (2006); (4) Günther et al (2013); (5) Klaassen et al (2013). b) Launch epochs from radial velocities in the X-shooter spectra.…”

Section: Kinematics: Proper Motions Vs Radial Velocitiesmentioning

confidence: 99%

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Ellerbroek

Podio

Dougados

et al. 2014

A&A

Self Cite

131

View full text Add to dashboard Cite

Herbig Ae/Be stars are intermediate-mass pre-main sequence stars surrounded by circumstellar dust disks. Some are observed to produce jets, whose appearance as a sequence of shock fronts (knots) suggests a past episodic outflow variability. This "jet fossil record" can be used to reconstruct the outflow history. We present the first optical to near-infrared (NIR) spectra of the jet from the Herbig Ae star HD 163296, obtained with VLT/X-shooter. We determine the physical conditions in the knots and also their kinematic "launch epochs". Knots are formed simultaneously on either side of the disk, with a regular interval of ∼16 yr. The velocity dispersion versus jet velocity and the energy input are comparable between both lobes. However, the mass-loss rate, velocity, and shock conditions are asymmetric. We findṀ jet /Ṁ acc ∼ 0.01−0.1, which is consistent with magneto-centrifugal jet launching models. No evidence of any dust is found in the high-velocity jet, suggesting a launch region within the sublimation radius (<0.5 au). The jet inclination measured from proper motions and radial velocities confirms that it is perpendicular to the disk. A tentative relation is found between the structure of the jet and the photometric variability of the central source. Episodes of NIR brightening were previously detected and attributed to a dusty disk wind. We report for the first time significant optical fadings lasting from a few days up to a year, coinciding with the NIR brightenings. These are very likely caused by dust lifted high above the disk plane, and this supports the disk wind scenario. The disk wind is launched at a larger radius than the high-velocity atomic jet, although their outflow variability may have a common origin. No significant relation between outflow and accretion variability could be established. Our findings confirm that this source undergoes periodic ejection events, which may be coupled with dust ejections above the disk plane.

show abstract

An Asymmetric Outflow from the Herbig Ae Star HD 163296

Cited by 50 publications

References 24 publications

Warm H₂O and OH in the disk around the Herbig star HD 163296

Warm H₂O and OH in the disk around the Herbig star HD 163296

The outflow history of two Herbig-Haro jets in RCW 36: HH 1042 and HH 1043

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Contact Info

Product

Resources

About

An Asymmetric Outflow from the Herbig Ae Star HD 163296

Cited by 50 publications

References 24 publications

Warm H2O and OH in the disk around the Herbig star HD 163296

Warm H2O and OH in the disk around the Herbig star HD 163296

The outflow history of two Herbig-Haro jets in RCW 36: HH 1042 and HH 1043

Relating jet structure to photometric variability: the Herbig Ae star HD 163296

Contact Info

Product

Resources

About

Warm H₂O and OH in the disk around the Herbig star HD 163296

Warm H₂O and OH in the disk around the Herbig star HD 163296