Complex Velocity Fields in the Shell of T Pyxidis

Margon, B.; Deutsch, Eric W.

doi:10.1086/311310

Cited by 9 publications

(8 citation statements)

References 13 publications

(25 reference statements)

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“…Steeghs & Casares 2002), where it is thought to be produced by a fluorescence process as the front side of the donor is strongly irradiated by the hot accretor. The Bowen blend was clearly visible in the spectrum of T Pyx obtained by Margon & Deutsch (1998), and based on this, we were hoping to detect narrow components associated with the donor. However, no narrow donor star features were found in the blend.…”

Section: Discussionmentioning

confidence: 88%

The orbital period and system parameters of the recurrent nova T Pyx

Uthas

Knigge

Steeghs

2010

Monthly Notices of the Royal Astronomical Society

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T Pyx is a luminous recurrent nova that accretes at a much higher rate than is expected for its photometrically determined orbital period of about 1.8 h. We here provide the first spectroscopic confirmation of the orbital period, P = 1.8295 h (f = 13.118368 ± 1.1 × 10 −5 c d −1 ), based on time-resolved optical spectroscopy obtained at the Very Large Telescope and the Magellan telescope. We also derive an upper limit of the velocity semi-amplitude of the white dwarf, K1 = 17.9 ± 1.6 km s −1 , and estimate a mass ratio of q = 0.20 ± 0.03. If the mass of the donor star is estimated using the period-density relation and theoretical main-sequence mass-radius relation for a slightly inflated donor star, we find M 2 = 0.14 ± 0.03 M . This implies a mass of the primary white dwarf of M 1 = 0.7 ± 0.2 M . If the white-dwarf mass is >1 M , as classical nova models imply, the donor mass must be even higher. We therefore rule out the possibility that T Pyx has evolved beyond the period minimum for cataclysmic variables. We find that the system inclination is constrained to be i ≈ 10 • , confirming the expectation that T Pyx is a low-inclination system. We also discuss some of the evolutionary implications of the emerging physical picture of T Pyx. In particular, we show that epochs of enhanced mass transfer (like the present) may accelerate or even dominate the overall evolution of the system, even if they are relatively short-lived. We also point out that such phases may be relevant to the evolution of cataclysmic variables more generally.

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Section: Discussionmentioning

confidence: 88%

The orbital period and system parameters of the recurrent nova T Pyx

Uthas

Knigge

Steeghs

2010

Monthly Notices of the Royal Astronomical Society

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“…In many recent novae -including T Pyx -this material produces a detectable, line-emitting "nova shell" around the system. Following up on the announcement of Shahbaz et al (1997), O'Brien andCohen (1998) and Margon and Deutsch (1998) obtained spatially resolved spectroscopy of T Pyx and its nebula. These observations showed that the "jet lines" identified by Shahbaz et al are, in fact, nebular [N ii] lines associated with the nova shell.…”

Section: Do Cataclysmic Variables Launch Jets? Motivation and Backgroundmentioning

confidence: 99%

The case for jets in cataclysmic variables

Coppejans,

Knigge

2020

Preprint

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For decades cataclysmic variables (CVs) were thought to be one of the few classes of accreting compact objects to not launch jets, and have consequently been used to constrain jet launching models. However, recent theoretical and observational advances indicate that CVs do in fact launch jets. Specifically, it was demonstrated that their accretion-outflow cycle is analogous to that of their higher mass cousins -the X-ray Binaries (XRBs). Subsequent observations of the CV SS Cygni confirmed this and have consistently shown radio flaring equivalent to that in the XRBs that marks a transient jet. Based on this finding and the emission properties, several studies have concluded that the radio emission is most likely from a transient jet. Observations of other CVs, while not conclusive, are consistent with this interpretation. However, the issue is not yet settled. Later observations have raised a number of questions about this model, as well as about potential alternative radio emission mechanisms. CVs are non-relativistic and many have well-determined distances; these properties would make them ideal candidates with which to address many of our outstanding questions about fundamental jet physics. Here we review the case for jets in CVs, discuss the outstanding questions and issues, and outline the future work necessary to conclusively answer the question of whether CVs launch jets.

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“…From the comparison of the size of the nebula at different epochs, they derived an upper limit of about only 40 km s −1 (but assumed d = 1500 pc) on the systematic expansion velocity of the knots. Instead, both Margon &Deutsch (1998) andO'Brien &Cohen (1998), in a study of the alleged jet components in the Hα line (Shabaz et al 1997), identified these features as due to the [NII] 6548, 6584 lines and interpreted their wavelength shifts as produced by an expansion velocity of about 500 km s −1 along the line of sight through the center of the shell. If some of these "variable knots" happen to lie within the IUE PSF they may also explain the emission line changes and the unusual spectroscopic signatures in the UV spectrum of T Pyx.…”

Section: ) the (Irradiated) Chromosphere Of The M Dwarf Companionmentioning

confidence: 99%

“…Shabbaz et al (1997) interpreted the presence of two spectral features on either side of Hα as the signature of a bi-polar, highvelocity, highly collimated jet, but subsequent studies by Margon & Deutsch (1998) and by O'Brien & Cohen (1998) have shown that these features are instead emission in the [NII] 6548 and 6584 lines from a complex velocity field in the surrounding shell.…”

Section: Introductionmentioning

confidence: 99%

The secrets of T Pyxidis

Gilmozzi¹,

Selvelli²

2006

A&A

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Aims. We study the UV spectral behavior of the recurrent nova T Pyx during 16 years of IUE observations. Methods. We examined both the IUE line-by-line images and the extracted spectra in order to understand the reality and the origin of the observed spectral variations. We compare different extraction methods and their influence on the spectrum of an extended object. Results. The UV continuum of T Pyx has remained nearly constant in slope and intensity over this time interval, without any indication of long-term trends. The reddening determined from the UV data is E B−V = 0.25 ± 0.02. The best single-curve fit to the dereddened UV continuum is a power-law distribution ∝λ −2.33 . The tail of this curve agrees well with the B, V, and J magnitudes of T Pyx, indicating that the contribution of the secondary star is negligible. One peculiar aspect of T Pyx is that most emission lines (the strongest ones being those of CIV 1550 and HeII 1640) show substantial changes both in intensity and detectability, in contrast to the near constancy of the continuum. Several individual spectra display emission features that are difficult to identify, suggesting a composite spectroscopic system. We tentatively ascribe the origin of these transient emission features either to loops and jets from the irradiated secondary or to moving knots of the surrounding nebula that are (temporarily) projected in front of the system. The inspection of all IUE line-by-line images has led to the detection of emission spikes outside the central strip of the spectrum, which in some cases seem associated to known emission features in the (main) spectrum. A comparison with other ex-novae reveals a surprising similarity to the spectrum of the very-slow nova HR Del, whose white dwarf primary has a mass that is allegedly about one half that of T Pyx.

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Complex Velocity Fields in the Shell of T Pyxidis

Cited by 9 publications

References 13 publications

The orbital period and system parameters of the recurrent nova T Pyx

The orbital period and system parameters of the recurrent nova T Pyx

The case for jets in cataclysmic variables

The secrets of T Pyxidis

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