Pulsed accretion in a variable protostar

Muzerolle, James; Furlan, Elise; Flaherty, Kevin; Balog, Z.; Gutermuth, Robert

doi:10.1038/nature11746

Cited by 57 publications

(63 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their periodic creation of knots (during the derived "launch epochs") does not necessarily have to take place in the disk, but it can be the consequence of (quasi-)periodic processes in the star-disk system. These include disk instabilities (e.g., Zhu et al 2007;D'Angelo & Spruit 2012), the interplay between disk rotation and magnetospheric accretion (Romanova et al 2012), stellar magnetic cycles (Armitage 1995;Donati et al 2003) or interaction with a companion (Muzerolle et al 2013). The periodicity of 16 yr corresponds to a Keplerian orbit at 6 au.…”

Section: The Nature Of "Launch Epochs"mentioning

confidence: 99%

See 1 more Smart Citation

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

Ellerbroek

Podio

Dougados

et al. 2014

A&A

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

Section: The Nature Of "Launch Epochs"mentioning

confidence: 99%

“…Muzerolle et al 2013;Rodriguez et al 2013). During the periastron passage of the companion the accretion and outflow activity in the disk is expected to be enhanced (Artymowicz & Lubow 1996).…”

Section: Optical Fading Nir Brightening: Dust In the Wind?mentioning

confidence: 99%

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

Ellerbroek

Podio

Dougados

et al. 2014

A&A

131

View full text Add to dashboard Cite

show abstract

“…The evidence is particularly scarce for the case of protostars. Only a few class I or young class II objects have been reported to show infrared bursts related to accretion (e.g., Reipurth & Aspin 2004;Caratti o Garatti et al 2011;Covey et al 2011;Fischer et al 2012;Muzerolle et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Pre- And Post-Burst Radio Observations of the Class 0 Protostar Hops 383 in Orion

Galván-Madrid¹,

Rodrı́guez

Liu

et al. 2015

ApJ

View full text Add to dashboard Cite

There is increasing evidence that episodic accretion is a common phenomenon in Young Stellar Objects (YSOs). Recently, the source HOPS 383 in Orion was reported to have a 35 mid-infrared-and bolometric-luminosity increase between 2004 and 2008, constituting the first clear example of a class 0 YSO (a protostar) with a large accretion burst. The usual assumption that in YSOs accretion and ejection follow each other in time needs to be tested. Radio jets at centimeter wavelengths are often the only way of tracing the jets from embedded protostars. We searched the Very Large Array archive for the available observations of the radio counterpart of HOPS 383. The data show that the radio flux of HOPS 383 varies only mildly from 1998 January to 2014 December, staying at the level of ∼200-300 μJy in the X band (∼9 GHz), with a typical uncertainty of 10-20 μJy in each measurement. We interpret the absence of a radio burst as suggesting that accretion and ejection enhancements do not follow each other in time, at least not within timescales shorter than a few years. Time monitoring of more objects and specific predictions from simulations are needed to clarify the details of the connection betwen accretion and jets/winds in YSOs.

show abstract

“…They are also expected to exist around supermassive black hole (SMBH) binaries as a consequence of accretion from the interstellar medium following galaxy mergers (e.g., Begelman et al 1980;Ivanov et al 1999;Milosavljević & Phinney 2005;Escala et al 2005;Mayer et al 2007;Dotti et al 2007;Cuadra et al 2009;Chapon et al 2013). Understanding the dynamical behavior of circumbinary discs has important applications for a variety of astrophysical problems, including variable accretion in both young stellar objects (Jensen et al 2007;Muzerolle et al 2013; Bary & Petersen 2014) and active galactic nuclei rjm456@cornell.edu (e.g., D'Orazio et al 2015), circumbinary planet formation (Paardekooper et al 2012;Meschiari 2012;Rafikov 2013;Silsbee & Rafikov 2015), and long-term binary orbital evolution (e.g., Armitage & Natarajan 2002;Haiman et al 2009;Chang et al 2010;Roedig et al 2012). In this paper we carry out a suite of numerical simulations to investigate the structure, morphology, and variability of circumbinary accretion on a wide range of time-scales, as well as the longterm angular momentum transfer between the binary and the circumbinary disc.…”

Section: Introductionmentioning

confidence: 99%

Viscous hydrodynamics simulations of circumbinary accretion discs: variability, quasi-steady state and angular momentum transfer

Miranda

Muñoz

Lai

2016

Mon. Not. R. Astron. Soc.

193

267

View full text Add to dashboard Cite

We carry out numerical simulations of circumbinary discs, solving the viscous hydrodynamics equations on a polar grid covering an extended disc outside the binary co-orbital region. We use carefully controlled outer boundary conditions and longterm integrations to ensure that the disc reaches a quasi-steady state, in which the time-averaged mass accretion rate onto the binary, Ṁ , matches the mass supply rate at the outer disc. We focus on binaries with comparable masses and a wide range of eccentricities (e B ). For e B 0.05, the mass accretion rate of the binary is modulated at about 5 times the binary period; otherwise it is modulated at the binary period. The inner part of the circumbinary disc (r 6a B ) generally becomes coherently eccentric. For low and high e B , the disc line of apsides precesses around the binary, but for intermediate e B (0.2 − 0.4), it instead becomes locked with that of the binary. By considering the balance of angular momentum transport through the disc by advection, viscous stress, and gravitational torque, we determine the time-averaged net angular momentum transfer rate to the binary, J . The specific angular momentum, l 0 = J / Ṁ , depends non-monotonically on e B . Contrary to previous claims, we find that l 0 is positive for most e B , implying that the binary receives net angular momentum, which may cause its separation to grow with time. The minimum l 0 occurs at intermediate e B (0.2 − 0.4), corresponding to the regime where the inner eccentric disc is apsidally aligned with the binary.

show abstract

Pulsed accretion in a variable protostar

Cited by 57 publications

References 42 publications

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

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

Pre- And Post-Burst Radio Observations of the Class 0 Protostar Hops 383 in Orion

Viscous hydrodynamics simulations of circumbinary accretion discs: variability, quasi-steady state and angular momentum transfer

Contact Info

Product

Resources

About