SYMBIOJETS · Jets in Symbiotic Stars -- the Rosetta stone for jet formation
FP7 — People (Marie Curie Actions)
- Duration
- 2010-04-01 → 2012-03-31
- EU contribution
- €30,000
- Participants
- 1
- Scheme
- MC-ERG
Lines connect the coordinator with its partners.
Results in brief
Jets in Symbiotic Stars - the Rosetta stone for jet formation
On 31 August 31 2010, the project was terminated early due to the move of the researcher to a new position as Assistant Professor at the Eberhard Karls Universität Tübingen, Germany. Since the new position had been accepted already in February and since it could not be foreseen, whether the grant could be used at all before the move, work on the project started upon availability of the funds in End of June. In the period of 15 - 21 August, the researcher attended the 17th European White Dwarf Workshop in Tübingen, Germany. Thus in the remaining six weeks, only preliminary investigations could be performed, which will be described below. The project is now part of a larger proposal for an ERC Starting Independent Researcher Grant submitted in last October and will be tackled by future students in Tübingen. The first step described in the proposal was determining the kinematics of single features and knots in the jet of R Aqr. Therefore we started an extensive search through the literature, looking for observations where distinct features of the jet have been detected and/or their positions have been inferred and listed. Mäkinen et al. (2004) studied the jet in radio wavelengths in great detail in two epochs; Paresce & Hack (1994) presented observations with the Hubble Space Telescope (HST) in two epochs. From the listed positions it can be now inferred that there are repeated jet ejections events every about 17 years. However, this value has to be confirmed with more data. We therefore downloaded the available data from the Hubble Space Telescope (HST) of this object, and started reducing the data and inspecting the images. Proper motions of different structures in the images at different epochs will be measured directly. All results will be set in context with other observations in all wavelengths. Using the downloaded and reduced data of the HST, we will also infer the width of different jet knots by measuring the full-width half-maximum of the emission in different lines. Assuming that the width of different jet knots is identical with the width of the overall jet, these results can been compared with existing models by the researcher. This can be used for determining the radius of the part of the underlying accretion disk, from which the jets have been launched. These jet formation models launched from truncated accretion disks are part of a second project of the submitted proposal for an ERC Starting Independent Researcher Grant.
Data: CORDIS, © European Union
Project objective
Although jets are ubiquitous phenomena in many different astrophysical objects, their formation is still relatively unclear. We find jets in young stellar objects (YSO), in Planetary and Proto-Planetary nebulae, in Symbiotic Stars (SySs), in X-ray binaries and active galactic nuclei. The mass loss rate of all jets is found to be connected to the mass accretion rate of the underlying disk found in most objects. Hence it is believed that a single universal mechanism is responsible for ejecting jets in all classes. Since the necessary components seem to be well known and common to all objects, a more careful investigation of one specific class of objects should promise new insights also for the mechanisms in the other classes. From the observational point of view, one needs observational data with a high spatial resolution and kinematic informations from regions as near as possible to the jet source. These aspects make Symbiotic Stars as a class to ideal testbeds. Also for a theoretical reason, Symbiotic Stars are ideal for studying jet formation: their close relationship with cataclysmic variables (CVs). The short timescales in CVs make the latter the best understood accreting systems. Remarkably, although the WD in CVs may be highly magnetized, no jet emission has been detected thus far from these objects. Only hints for a present jet in one object (the dwarf nova SS Cyg) have been found very recently (Koerding et al. 2008). Even after confirmation of this result, the striking dichotomy concerning the fraction of jet sources to non-jet emitting objects in SySs (10 out of about 220) and that in CVs (one out of a few thousand) still lacks a compelling explanation. If we understand the propagating jet, we can compare it with analytical models and known relations between the properties inside the jet and those close to the disk, in order to infer basic parameters of the jet engine and to find intrinsic differences between SySs and CVs.
Original text from CORDIS.
Participants
- UNIVERSITA DEGLI STUDI DI TORINO · TorinoCoordinatorItaly
Links
Data: CORDIS, © European Union