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Journal articles on the topic 'Protostellar jets'

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Published: 8 June 2024

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1

Hayashi, Mitsuru, Kazunari Shibata, and Ryoji Matsumoto. "Flares and MHD Jets in Protostar." Symposium - International Astronomical Union 188 (1998): 232–33. http://dx.doi.org/10.1017/s0074180900114901.

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By using ASCA, Koyama et al. (1994, 1996) carried out a systematic survey of hard X-ray sources in molecular clouds and revealed that protostars are strong hard X-ray emitting sources. Some of them show flare-like activities. Protostellar flares differ from solar flares in their total energy(1035-36 erg), size(several times the radius of protostar), and higher temperature(8keV). Protostellar flares are also observed in lower energy band by ROSAT in YLW15 (Grosso et al. 1997). By extending the model of solar flares associated with footpoint shearing motion, we proposed a model of protostellar flares in which the magnetic field connecting the protostar and the disk disrupt by twist injection from the rotating disk(Hayashi et al. 1996).

2

Vorobyov, Eduard I., Vardan G. Elbakyan, Adele L. Plunkett, Michael M. Dunham, Marc Audard, Manuel Guedel, and Odysseas Dionatos. "Knotty protostellar jets as a signature of episodic protostellar accretion?" Astronomy & Astrophysics 613 (May 2018): A18. http://dx.doi.org/10.1051/0004-6361/201732253.

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Aims. We aim to study the causal link between the knotty jet structure in CARMA 7, a young Class 0 protostar in the Serpens South cluster, and episodic accretion in young protostellar disks. Methods. We used numerical hydrodynamics simulations to derive the protostellar accretion history in gravitationally unstable disks around solar-mass protostars. We compared the time spacing between luminosity bursts Δτmod, caused by dense clumps spiralling on the protostar, with the differences of dynamical timescales between the knots Δτobs in CARMA 7. Results. We found that the time spacing between the bursts have a bi-modal distribution caused by isolated and clustered luminosity bursts. The former are characterized by long quiescent periods between the bursts with Δτmod = a few × (103–104) yr, whereas the latter occur in small groups with time spacing between the bursts Δτmod = a few × (10–102) yr. For the clustered bursts, the distribution of Δτmod in our models can be fit reasonably well to the distribution of Δτobs in the protostellar jet of CARMA 7, if a certain correction for the (yet unknown) inclination angle with respect to the line of sight is applied. The Kolmogorov–Smirnov test on the model and observational data sets suggests the best-fit values for the inclination angles of 55–80°, which become narrower (75–80°) if only strong luminosity bursts are considered. The dynamical timescales of the knots in the jet of CARMA 7 are too short for a meaningful comparison with the long time spacings between isolated bursts in our models. Moreover, the exact sequences of time spacings between the luminosity bursts in our models and knots in the jet of CARMA 7 were found difficult to match. Conclusions. Given the short time that has passed since the presumed luminosity bursts (tens to hundreds years), a possible overabundance of the gas-phase CO in the envelope of CARMA 7 compared to what could be expected from the current luminosity may be used to confirm the burst nature of this object. More sophisticated numerical models and observational data on jets with longer dynamical timescales are needed to further explore the possible causal link between luminosity bursts and knotty jets.

3

Reipurth, Bo, Luis F. Rodrguez, Guillem Anglada, and John Bally. "Radio Continuum Jets from Protostellar Objects." Astronomical Journal 127, no. 3 (March 2004): 1736–46. http://dx.doi.org/10.1086/381062.

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4

Stone, James M., and Philip E. Hardee. "Magnetohydrodynamic Models of Axisymmetric Protostellar Jets." Astrophysical Journal 540, no. 1 (September 2000): 192–210. http://dx.doi.org/10.1086/309289.

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5

de Gouveia dal Pino, Elisabete M., and Willy Benz. "Three-dimensional simulations of protostellar jets." Astrophysical Journal 410 (June 1993): 686. http://dx.doi.org/10.1086/172785.

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6

Reipurth, Bo, John Bally, Robert A. Fesen, and David Devine. "Protostellar jets irradiated by massive stars." Nature 396, no. 6709 (November 1998): 343–45. http://dx.doi.org/10.1038/24562.

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7

Zinnecker, Hans, and Mark J. McCaughrean. "Infrared Jets from Protostars: The case of HH212." International Astronomical Union Colloquium 163 (1997): 531–35. http://dx.doi.org/10.1017/s0252921100043153.

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AbstractWe describe the appearance and significance of HH212, the most symmetric two-sided molecular hydrogen jet/counterjet system yet discovered. This prototype embedded protostellar H2 jet emanates from a low-luminosity isolated protostar in Orion. It exhibits matched pairs of knots and bow-shocks interpreted as arising from a time-variable source, which we take to indicate that protostellar accretion through the encircling disk is non-steady and pulsed.

8

Spruit, H. C. "Jets from Compact Objects." Symposium - International Astronomical Union 195 (2000): 113–22. http://dx.doi.org/10.1017/s0074180900162849.

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Some topics in the theory of jets are reviewed. These include jet precession, unconfined jets, the origin of knots, the internal shock model as a unifying theme from protostellar jets to gamma-ray bursts, relations between the Blandford-Znajek and MHD disk-wind models, and jet collimation in magnetic acceleration models.

9

Shibata, Kazunari. "Theory of Flares and MHD Jets." Symposium - International Astronomical Union 188 (1998): 9–12. http://dx.doi.org/10.1017/s0074180900114317.

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Recent development on the theory and numerical modeling of solar flares and jets is reviewed with emphasis on the magnetic reconnection model. Application to protostellar flares and jets is also discussed.

10

Podio, Linda, Benoit Tabone, and Claudio Codella. "Protostellar jets: A statistical view with the CALYPSO IRAM-PdBI survey." EPJ Web of Conferences 265 (2022): 00037. http://dx.doi.org/10.1051/epjconf/202226500037.

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In the context of the CALYPSO IRAM-PdBI Lai•ge Program we performed the first statistical survey of protostellar jets by analysing molecular emission in a sample of 21 protostars covering a broad range of internal luminosities (Lint from 0.035 L⊙ to 47 L⊙). We find that the outflow phenomenon is ubiquitous in our sample of protostars, with wide-angle outflows detected in CO (2 - 1) in all sources, and high-velocity collimated jets detected in SiO (5-4) in 80% of the sources with Lint > 1 L⊙. The protostellar flows have an onion-like structure, with the SiO jet (opening angle, α ~ 10°) nested into a wider angle SO (α ~ 15°) and CO (α ~ 25°) outflows. Interestingly, protostellar jets show several properties in common with the atomic jets associated with more evolved sources (106 yr), e.g. one third of the jets show velocity asymmetry of ~ 1.3-2 between the two lobes, and the mass-loss rates are ~ 1% - 50% of the mass accretion rates. This suggests that the same launching mechanism is at work and that the correlation between mass ejection and mass accretion holds along the star-formation process from 104 yr up to a few Myr.

11

Machida, Masahiro N. "PROTOSTELLAR JETS ENCLOSED BY LOW-VELOCITY OUTFLOWS." Astrophysical Journal 796, no. 1 (November 7, 2014): L17. http://dx.doi.org/10.1088/2041-8205/796/1/l17.

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12

Shu, Frank H., and Hsien Shang. "Protostellar X-Rays, Jets, and Bipolar Outflows." Symposium - International Astronomical Union 182 (1997): 225–39. http://dx.doi.org/10.1017/s0074180900061672.

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We review the theory of x-winds in young stellar objects (YSOs). In particular, we consider how a model where the central star does not corotate with the inner edge of the accretion disk may help to explain the enhanced emission of X-rays from embedded protostars. We argue, however, that the departure from corotation is not large, so a mathematical formulation that treats the long-term average state as steady and axisymmetric represents a useful approximation. Magnetocentrifugally driven x-winds of this description collimate into jets, and their interactions with the surrounding molecular cloud cores of YSOs yield bipolar molecular outflows.

13

Rudolph, Alexander L. "Evidence for Protostellar Wind-Cloud Interactions." International Astronomical Union Colloquium 140 (1994): 195–98. http://dx.doi.org/10.1017/s0252921100019461.

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AbstractRecent molecular line observations of HH flows (HH objects and optical jets) have revealed abundant evidence of interactions between protostellar winds and the surrounding molecular clouds. HCO+ observations taken with the BIMA Array have traced out the distribution of both stationary and high-velocity gas near the protostellar objects HH 7-11, L1551, and HH 34.

14

Liffman, Kurt, and Anna Siora. "Toroidal Fields: a Driving Mechanism for Protostellar Jets." International Astronomical Union Colloquium 163 (1997): 754–56. http://dx.doi.org/10.1017/s0252921100043803.

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AbstractWe propose that a toroidal magnetic field is the main driving component of a protostellar jet. We discuss how the ram pressure of the jet may damp a Parker-like instability and provide a stable environment for a jet flow.

15

Machida, Masahiro N., Kazuyuki Omukai, Tomoaki Matsumoto, and Shu-ichiro Inutsuka. "The First Jets in the Universe: Protostellar Jets from the First Stars." Astrophysical Journal 647, no. 1 (August 1, 2006): L1—L4. http://dx.doi.org/10.1086/507326.

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16

Fendt, Christian, Bhargav Vaidya, Oliver Porth, and Somayeh Sheikh Nezami. "MHD simulations of jet formation - protostellar jets & applications to AGN jets." Proceedings of the International Astronomical Union 6, S275 (September 2010): 383–91. http://dx.doi.org/10.1017/s1743921310016443.

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AbstractJet formation MHD simulations are presented considering a variety of model setups. The first approach investigates the interrelation between the disk magnetisation profile and jet collimation. Our results suggest (and quantify) that outflows launched from a very concentrated region at the inner disk tend to be weakly collimated. In the second approach, jet formation is investigated from a magnetic field configuration consisting of a stellar dipole superposed by a strong disk field. We find that the central dipole considerably de-collimates the disk wind. In addition, reconnection flares are launched in the interaction region of disk and stellar magnetic field, subsequently changing the outflow mass flux by factors of two. The time interval between flare ejection is about 1000 Keplerian periods - surprisingly similar to the observed time lag between jet knots. The third approach considers radiative pressure effects on jet collimation - an environment which is interesting mainly for outflows from massive young stars (but also for relativistic jets). Finally we present relativistic MHD simulations of jet formation from accretion disks extenting the previous non-relativistic approaches.

17

Salmeron, Raquel, and Trevor Ireland. "Magnetocentrifugal jets and chondrule formation in protostellar disks." Proceedings of the International Astronomical Union 8, S299 (June 2013): 228–29. http://dx.doi.org/10.1017/s1743921313008442.

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AbstractChondrite meteorites are the building blocks of the solar nebula, out of which our Solar System formed. They are a mixture of silicate and oxide objects (chondrules and refractory inclusions) that experienced very high temperatures, set in a matrix that remained cold. Their prevalence suggests that they formed through a very general process, closely related to stellar and planet formation. However the nature and properties of the responsible mechanism have remained unclear. The evidence for a hot solar nebula provided by this material seems at odds with astrophysical observations of forming stars. These indicate that the typical temperatures of protostellar disks are too low to melt and vapourise silicate minerals at the radial distances sampled by chondrule-bearing meteorites. Here, we show that processing of precursors in a protostellar outflow at radial distances of about 1 – 3 AU can heat them to their melting points and explain their basic properties, while retaining association with the colder matrix.

18

Rosen, A., and M. D. Smith. "Simulations of evolving or outbursting molecular protostellar jets." Monthly Notices of the Royal Astronomical Society 343, no. 1 (July 21, 2003): 181–91. http://dx.doi.org/10.1046/j.1365-8711.2003.06654.x.

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19

Bate, M. R., I. A. Bonnell, C. J. Clarke, S. H. Lubow, G. I. Ogilvie, J. E. Pringle, and C. A. Tout. "Observational implications of precessing protostellar discs and jets." Monthly Notices of the Royal Astronomical Society 317, no. 4 (October 1, 2000): 773–81. http://dx.doi.org/10.1046/j.1365-8711.2000.03648.x.

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20

Cécere, Mariana, Pablo F. Velázquez, Anabella T. Araudo, Fabio De Colle, Alejandro Esquivel, Carlos Carrasco-González, and Luis F. Rodríguez. "A STUDY OF RADIO POLARIZATION IN PROTOSTELLAR JETS." Astrophysical Journal 816, no. 2 (January 5, 2016): 64. http://dx.doi.org/10.3847/0004-637x/816/2/64.

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21

Djupvik, A. A., T. Liimets, H. Zinnecker, A. Barzdis, E. A. Rastorgueva-Foi, and L. R. Petersen. "Proper motions of embedded protostellar jets in Serpens." Astronomy & Astrophysics 587 (February 19, 2016): A75. http://dx.doi.org/10.1051/0004-6361/201526532.

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22

Kamenetzky, Adriana Rodríguez. "Nonthermal Emission and Particle Acceleration in Protostellar Jets." Publications of the Astronomical Society of the Pacific 130, no. 993 (October 2, 2018): 117001. http://dx.doi.org/10.1088/1538-3873/aae14d.

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23

Fendt, C., and M. Čemeljić. "Formation of protostellar jets – effects of magnetic diffusion." Astronomy & Astrophysics 395, no. 3 (November 18, 2002): 1045–60. http://dx.doi.org/10.1051/0004-6361:20021442.

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24

Nisini, Brunella. "Mid and Far Infrared Observations of Protostellar Jets." Astrophysics and Space Science 287, no. 1-4 (2003): 207–12. http://dx.doi.org/10.1023/b:astr.0000006225.10230.dd.

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25

Camenzind, Max. "Energetics, Collimation and Propagation of Galactic Protostellar Outflows." Symposium - International Astronomical Union 182 (1997): 241–58. http://dx.doi.org/10.1017/s0074180900061684.

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Formation of jets in low-mass protostellar objects and young pre-main sequence stars is ultimately related to the existence of some gaseous disk around a rapidly rotating central object. This configuration has deep parallels to extragalactic systems such as radio galaxies and quasars. Rotating black holes are still thought to be the prime-mover behind the activity detected in centers of galaxies, while, in the case of protostellar jets, rapidly rotating stars and disks are responsible for the ejection of bipolar outflows. In both cases, magnetic fields are invoked for the acceleration, the collimation and propagation of these outflows. The ultimate rooting of these fields is still under debate. We discuss models where winds injected into rapidly rotating magnetospheres of the central object drive the outflows. From these considerations it follows that the jets of young stellar objects can only be produced magnetically and that their progagation is determined by their magnetic properties. Such jets have low Mach numbers ≃ 2 and their instabilities are dominated by the pinch mode. Knots closest to the source are attributed to compression by the time-dependent pinches. Multiple bow shocks occur on longer time-scales (a few thousand years) and are attributed to variations in the magnetospheric structure of the star, or the disk.

26

Guszejnov, Dávid, Michael Y. Grudić, Philip F. Hopkins, Stella S. R. Offner, and Claude-André Faucher-Giguère. "STARFORGE: the effects of protostellar outflows on the IMF." Monthly Notices of the Royal Astronomical Society 502, no. 3 (February 2, 2021): 3646–63. http://dx.doi.org/10.1093/mnras/stab278.

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ABSTRACT The initial mass function (IMF) of stars is a key quantity affecting almost every field of astrophysics, yet it remains unclear what physical mechanisms determine it. We present the first runs of the STAR FORmation in Gaseous Environments project, using a new numerical framework to follow the formation of individual stars in giant molecular clouds (GMCs) using the gizmo code. Our suite includes runs with increasingly complex physics, starting with isothermal ideal magnetohydrodynamics (MHD) and then adding non-isothermal thermodynamics and protostellar outflows. We show that without protostellar outflows the resulting stellar masses are an order of magnitude too high, similar to the result in the base isothermal MHD run. Outflows disrupt the accretion flow around the protostar, allowing gas to fragment and additional stars to form, thereby lowering the mean stellar mass to a value similar to that observed. The effect of jets upon global cloud evolution is most pronounced for lower mass GMCs and dense clumps, so while jets can disrupt low-mass clouds, they are unable to regulate star formation in massive GMCs, as they would turn an order unity fraction of the mass into stars before unbinding the cloud. Jets are also unable to stop the runaway accretion of massive stars, which could ultimately lead to the formation of stars with masses ${\gt}500\, \mathrm{M}_{\rm \odot }$. Although we find that the mass scale set by jets is insensitive to most cloud parameters (i.e. surface density, virial parameter), it is strongly dependent on the momentum loading of the jets (which is poorly constrained by observations) as well as the temperature of the parent cloud, which predicts slightly larger IMF variations than observed. We conclude that protostellar jets play a vital role in setting the mass scale of stars, but additional physics are necessary to reproduce the observed IMF.

27

FRANK, ADAM. "PROTOSTELLAR OUTFLOWS: NEW PERSPECTIVES ON MESOSCOPIC STRUCTURE AND MACROSCOPIC FEEDBACK." Modern Physics Letters A 24, no. 15 (May 20, 2009): 1167–85. http://dx.doi.org/10.1142/s0217732309030989.

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This paper presents a brief review of new perspectives in the field of protostellar outflows concentrating on scales above those associated with the launch region (L > 10 AU ). The formation and propagation of protostellar or Young Stellar Object (YSO) jets and collimated outflows has been intensively studied over the last 30 years with enormous progress being made in both theory and observations. As both the resolution and integration of observational platforms increases new features are revealed which have shifted the emphasis of research efforts. In this paper we review results in two different domains of YSO outflows research which focus on these new perspectives. We first review attempts to model jets as intrinsically heterogeneous (clumpy) systems. The role of sub-radial clumps (rc < rj) within a jet are explored and these models are differentiated from the classic paradigm of pulsed jets. In the second section we look at YSO jets in a global, environmental context. The ability of YSO jets and outflows to generate and/or sustain turbulence in star forming environments has been suggested as a major source of feedback in young clusters. Until recently this suggestion has been untested via direct simulations. We review new work on star formation outflow feedback and discuss issues for future studies.

28

Stone, James M., and Michael L. Norman. "Numerical Simulations of Protostellar Jets with Nonequilibrium Cooling. II. Models of Pulsed Jets." Astrophysical Journal 413 (August 1993): 210. http://dx.doi.org/10.1086/172989.

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29

Banerjee, Robi, Ralf S. Klessen, and Christian Fendt. "Can Protostellar Jets Drive Supersonic Turbulence in Molecular Clouds?" Astrophysical Journal 668, no. 2 (October 20, 2007): 1028–41. http://dx.doi.org/10.1086/521097.

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30

Bonito, R., S. Orlando, G. Peres, F. Favata, and R. Rosner. "X-rays from protostellar jets: emission from continuous flows." Astronomy & Astrophysics 462, no. 2 (November 13, 2006): 645–56. http://dx.doi.org/10.1051/0004-6361:20065236.

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31

Stanke, T., M. J. McCaughrean, and H. Zinnecker. "An unbiased H2survey for protostellar jets in Orion A." Astronomy & Astrophysics 392, no. 1 (August 22, 2002): 239–66. http://dx.doi.org/10.1051/0004-6361:20020763.

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32

Shang, Hsien, Frank H. Shu, and Alfred E. Glassgold. "Synthetic Images and Long-Slit Spectra of Protostellar Jets." Astrophysical Journal 493, no. 2 (February 1, 1998): L91—L94. http://dx.doi.org/10.1086/311135.

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33

Fridlund, C. V. Malcolm, and René Liseau. "Two Jets from the Protostellar System L1551 IRS 5." Astrophysical Journal 499, no. 1 (May 20, 1998): L75—L77. http://dx.doi.org/10.1086/311352.

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34

Moraghan, Anthony, Michael D. Smith, and Alexander Rosen. "Velocity study of axisymmetric protostellar jets with molecular cooling." Monthly Notices of the Royal Astronomical Society 371, no. 3 (September 21, 2006): 1448–58. http://dx.doi.org/10.1111/j.1365-2966.2006.10791.x.

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35

Ramsey, Jon P., and David A. Clarke. "SIMULATING PROTOSTELLAR JETS SIMULTANEOUSLY AT LAUNCHING AND OBSERVATIONAL SCALES." Astrophysical Journal 728, no. 1 (January 19, 2011): L11. http://dx.doi.org/10.1088/2041-8205/728/1/l11.

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36

Caratti o Garatti, A., J. Eislöffel, D. Froebrich, B. Nisini, T. Giannini, and L. Calzoletti. "First detection of acceleration and deceleration in protostellar jets?" Astronomy & Astrophysics 502, no. 2 (June 4, 2009): 579–97. http://dx.doi.org/10.1051/0004-6361/200911664.

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37

Gritschneder, Matthias, Andreas Burkert, Thorsten Naab, and Stefanie Walch. "Pillars, Jets and Dynamical Features." Proceedings of the International Astronomical Union 6, S270 (May 2010): 319–22. http://dx.doi.org/10.1017/s1743921311000573.

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AbstractWe present high resolution simulations on the impact of ionizing radiation on turbulent molecular clouds. The combination of hydrodynamics, gravitational forces and ionization in the tree-SPH code iVINE naturally leads to the formation of elongated filaments and clumps, which are in excellent agreement with the pillars observed around HII regions. Including gravity the formation of a second generation of low-mass stars with surrounding protostellar disks is triggered at the tips of the pillars, as also observed. A parameter study allows us to determine the physical conditions under which irregular structures form and whether they resemble large pillars or a system of small, isolated globules.

38

Dutta, Somnath, Chin-Fei Lee, Naomi Hirano, Tie Liu, Doug Johnstone, Sheng-Yuan Liu, Ken’ichi Tatematsu, et al. "ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): Evidence for a Molecular Jet Launched at an Unprecedented Early Phase of Protostellar Evolution." Astrophysical Journal 931, no. 2 (June 1, 2022): 130. http://dx.doi.org/10.3847/1538-4357/ac67a1.

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Abstract Protostellar outflows and jets play a vital role in star formation as they carry away excess angular momentum from the inner disk surface, allowing the material to be transferred toward the central protostar. Theoretically, low-velocity and poorly collimated outflows appear from the beginning of the collapse at the first hydrostatic core (FHSC) stage. With growing protostellar core mass, high-density jets are launched, entraining an outflow from the infalling envelope. Until now, molecular jets have been observed at high velocity (≳100 km s−1) in early Class 0 protostars. We, for the first time, detect a dense molecular jet in SiO emission with low velocity (∼4.2 km s−1, deprojected ∼24 km s−1) from source G208.89–20.04Walma (hereafter G208Walma) using ALMA Band 6 observations. This object has some characteristics of FHSCs, such as a small outflow/jet velocity, extended 1.3 mm continuum emission, and N 2D+ line emission. Additional characteristics, however, are typical of early protostars: collimated outflow and SiO jet. The full extent of the outflow corresponds to a dynamical timescale of ∼ 930 − 100 + 200 yr. The spectral energy distribution also suggests a very young source having an upper limit of T bol ∼ 31 K and L bol ∼ 0.8 L ⊙. We conclude that G208Walma is likely in the transition phase from FHSC to protostar, and the molecular jet has been launched within a few hundred years of initial collapse. Therefore, G208Walma may be the earliest object discovered in the protostellar phase with a molecular jet.

39

Koide, Shinji, Kazunari Shibata, and Takahiro Kudoh. "Numerical Simulation of Relativistic Jet Formation in Black Hole Magnetosphere." Symposium - International Astronomical Union 188 (1998): 415–16. http://dx.doi.org/10.1017/s0074180900115797.

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The radio jets ejected from active galactic nuclei (AGNs) sometimes show proper motions with apparent velocity exceeding the speed of light. This phenomenon, called superluminal motion, is explained as relativistic jets propagating in a direction almost toward us, and has been thought to be ejected from the close vicinity of hypothetical supermassive black holes powering AGNs (Rees 1996). The magnetic mechanism has been proposed not only for AGN jets (Lovelace 1976; Blandford & Payne 1983) but also for protostellar jets (Pudritz & Norman 1986; Uchida & Shibata 1985; Shibata & Uchida 1986), although no one has yet performed nonsteady general relativistic magnetohydrodynamic (GRMHD) numerical simulations on the formation of jets from the accretion disk around a black hole.

40

Sanna, A., L. Moscadelli, C. Goddi, M. Beltrán, C. L. Brogan, A. Caratti o Garatti, C. Carrasco-González, T. R. Hunter, F. Massi, and M. Padovani. "Protostellar Outflows at the EarliesT Stages (POETS)." Astronomy & Astrophysics 623 (March 2019): L3. http://dx.doi.org/10.1051/0004-6361/201834551.

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Centimeter continuum observations of protostellar jets have revealed knots of shocked gas where the flux density decreases with frequency. This spectrum is characteristic of nonthermal synchrotron radiation and implies both magnetic fields and relativistic electrons in protostellar jets. Here, we report on one of the few detections of a nonthermal jet driven by a young massive star in the star-forming region G035.02+0.35. We made use of the NSF’s Karl G. Jansky Very Large Array (VLA) to observe this region at C, Ku, and K bands with the A- and B-array configurations, and obtained sensitive radio continuum maps down to an rms of 10 μJy beam−1. These observations allow for a detailed spectral index analysis of the radio continuum emission in the region, which we interpret as a protostellar jet with a number of knots aligned with extended 4.5 μm emission. Two knots clearly emit nonthermal radiation and are found at similar distances, of approximately 10 000 au, at each side of the central young star, from which they expand at velocities of several hundred km s−1. We estimate both the mechanical force and the magnetic field associated with the radio jet, and infer a lower limit of 0.4 × 10−4 M⊙ yr−1 km s−1 and values in the range 0.7–1.3 mG.

41

Gusdorf, Antoine. "Feedback from young stars, the molecular signature of shocks and outflows." EPJ Web of Conferences 265 (2022): 00035. http://dx.doi.org/10.1051/epjconf/202226500035.

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Abstract:

Why do we study shocks ? Because they are there. Shocks are ubiquitous in the interstellar medium (ISM), where they constitute a major source of energy injection, together with photons and cosmic rays (CRs). Galactic shocks, and converging flows at the basis of the formation of molecular clouds and filaments, are examples of interstellar shocks. Shock waves are also generated during the birth, life and death of stars in the form of jets and protostellar outflows, stellar winds and supernovae and supernova remnants (SNRs). Hence, they are a major route of feedback of stars on galaxies. As such, they are a proficient tool to better understand the cycle of matter and energy in galaxies, but also the formation of stars. In this review, I will describe the recent advances on the study of shocks that can be observed and characterized with the IRAM instruments, with emphasis on the study of protostellar jets and outflows.

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De Colle, Fabio, Adriano H. Cerqueira, and Angels Riera. "TRANSVERSE VELOCITY SHIFTS IN PROTOSTELLAR JETS: ROTATION OR VELOCITY ASYMMETRIES?" Astrophysical Journal 832, no. 2 (November 29, 2016): 152. http://dx.doi.org/10.3847/0004-637x/832/2/152.

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43

Giannini, T., C. McCoey, A. Caratti o Garatti, B. Nisini, D. Lorenzetti, and D. R. Flower. "On the excitation of the infrared knots along protostellar jets." Astronomy & Astrophysics 419, no. 3 (May 7, 2004): 999–1014. http://dx.doi.org/10.1051/0004-6361:20040087.

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Cerqueira, A. H., J. Reyes-Iturbide, F. De Colle, and M. J. Vasconcelos. "PRINCIPAL COMPONENT ANALYSIS OF COMPUTED EMISSION LINES FROM PROTOSTELLAR JETS." Astronomical Journal 150, no. 2 (July 15, 2015): 45. http://dx.doi.org/10.1088/0004-6256/150/2/45.

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45

Cerqueira, Adriano H., Elisabete M. de Gouveia Dal Pino, and Marc Herant. "Magnetic Field Effects on the Head Structure of Protostellar Jets." Astrophysical Journal 489, no. 2 (1997): L185—L188. http://dx.doi.org/10.1086/316791.

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46

Liseau, R. "X-ray and He I 1.0830μm emission from protostellar jets." Astronomy & Astrophysics 459, no. 3 (September 12, 2006): 843–47. http://dx.doi.org/10.1051/0004-6361:20065990.

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47

Giannini, T., B. Nisini, S. Antoniucci, J. M. Alcalá, F. Bacciotti, R. Bonito, L. Podio, B. Stelzer, and E. T. Whelan. "THE DIAGNOSTIC POTENTIAL OF Fe LINES APPLIED TO PROTOSTELLAR JETS." Astrophysical Journal 778, no. 1 (November 6, 2013): 71. http://dx.doi.org/10.1088/0004-637x/778/1/71.

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48

Stone, James M. "Asymmetric Modes of the Kelvin-Helmholtz Instability in Protostellar Jets." Symposium - International Astronomical Union 182 (1997): 323–33. http://dx.doi.org/10.1017/s007418090006174x.

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Abstract:

The results of a detailed analysis of the linear properties, nonlinear growth, and saturation of asymmetric modes of the Kelvin-Helmholtz instability in cooling protostellar jet beams are summarized. In the linear regime, cooling can significantly alter the growth rate and wavelength of the most unstable mode in comparison to an adiabatic jet. In the nonlinear regime, sinusoidal oscillations at the maximum growth rate lead to distortions that will be observed as ‘wiggles’ or ‘kinks’ in the jet. Strong cooling behind shocks formed in the nonlinear regime can produce emission knots and filaments. In some cases, the modes grow until the jet is disrupted. Distortions in the surface of the jet drive shock spurs into the ambient gas, resulting in longitudinal acceleration. Rapid acceleration and entrainment of ambient gas is also observed if the jet is disrupted.

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de Gouveia Dal Pino, Elisabete M., and Mark Birkinshaw. "Three‐Dimensional Simulations of Protostellar Jets in Stratified Ambient Media." Astrophysical Journal 471, no. 2 (November 10, 1996): 832–46. http://dx.doi.org/10.1086/178011.

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Combet, C., and J. Ferreira. "The radial structure of protostellar accretion disks: influence of jets." Astronomy & Astrophysics 479, no. 2 (January 2, 2008): 481–91. http://dx.doi.org/10.1051/0004-6361:20078734.

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