The 2011 Outburst of Recurrent Nova T Pyx: Radio Observations Reveal the Ejecta Mass and Hint at Complex Mass Loss

Nelson, Thomas; Chomiuk, Laura; Roy, Nirupam; Sokoloski, J. L.; Mukai, K.; Krauss, M. I.; Mioduszewski, Amy J.; Rupen, M. P.; Weston, Jennifer

doi:10.1088/0004-637x/785/1/78

Cited by 53 publications

(74 citation statements)

References 52 publications

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“…This portion of V1324Sco's radio light curve is similar to the other novae that have been studied in the radio (e.g., Seaquist & Palimaka 1977;Hjellming et al 1979;Chomiuk et al 2012a;Nelson et al 2014;Weston et al 2016a).…”

Section: Second Radio Maximum and Determination Of Ejecta Masssupporting

confidence: 68%

“…Another possible explanation for flat-topped light curves was developed in the case of TPyx and proposed by Nelson et al (2014) and Chomiuk et al (2014b), where there is multiwavelength evidence that the bulk of the ejecta remained in a quasi-hydrostatic configuration around the binary until the end of the "flat top" period. In this nova, it appears that 1-2 months pass before the ejecta are accelerated to their terminal velocity and are expelled from the environs of the binary, although the physical origin of the delay remains a mystery (it is, perhaps, attributable to binary interaction with the quasi-static envelope).…”

Section: Discussion Of the Uvoir Light Curvementioning

confidence: 96%

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A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

Finzell

Chomiuk

Metzger

et al. 2018

ApJ

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It has recently been discovered that some, if not all, classical novae emit GeV gamma-rays during outburst, but the mechanisms involved in the production ofgamma-rays are still not well understood. We present here a comprehensive multiwavelength data set-from radio to X-rays-for the most gamma-ray-luminous classical nova to date, V1324 Sco. Using this data set, we show that V1324 Sco is a canonical dusty Fe II-type nova, with a maximum ejecta velocity of 2600 km s −1 and an ejecta mass of a few´-10 5  M . There is also evidence for complex shock interactions, including a double-peaked radio light curve which shows high brightness temperatures at early times. To explore why V1324Sco was so gamma-ray luminous, we present a model of the nova ejecta featuring strong internal shocks and find that higher gamma-ray luminosities result from higher ejecta velocities and/or mass-loss rates. Comparison of V1324Sco with other gamma-ray-detected novae does not show clear signatures of either, and we conclude that a larger sample of similarly well-observed novae is needed to understand the origin and variation of gamma-rays in novae.

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Section: Second Radio Maximum and Determination Of Ejecta Masssupporting

confidence: 68%

Section: Discussion Of the Uvoir Light Curvementioning

confidence: 96%

A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

Finzell

Chomiuk

Metzger

et al. 2018

ApJ

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“…But the observed ΔP is large, positive, and undeniable; so each of these would only raise ΔM, strengthening the conclusion that the WD erodes (or at least fails to increase its mass significantly; this would be the case if much of the ejected matter never resided on the WD). We note that radio observations (from the free-free emission) also suggest a large ΔM, probably near 10 -4 M ☉ (Nelson et al 2014). Thus it now seems unlikely that the white dwarf in T Pyx -once considered a fine ancestor for a Type Ia supernova -will ever increase its mass at all, much less reach 1.4 M ☉ .…”

Section: Eruption and Aftermathmentioning

confidence: 59%

T Pyxidis: death by a thousand novae

Patterson

Oksanen

Kemp

et al. 2016

Mon. Not. R. Astron. Soc.

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We report a 20-year campaign to track the 1.8 hour photometric wave in the recurrent nova T Pyxidis, using the global telescope network of the Center for Backyard Astrophysics. During 1996-2011, that wave was highly stable in amplitude and waveform, resembling the orbital wave commonly seen in supersoft binaries. The period, however, was found to increase on a timescale P/̇ = 3×10 5 years. This suggests a mass transfer rate in quiescence of ~10 -7M ☉ /yr, in substantial agreement with the accretion rate based on the star's luminosity. This is ~2000× greater than is typical for cataclysmic variables of that orbital period. During the posteruption quiescence (2012)(2013)(2014)(2015)(2016), the star continued on its merry but mysterious way -similar luminosity, similar P/̇ (2.4×10 5 years).The orbital signal became vanishingly weak (<0.003 mag) near maximum light of the 2011 eruption. By day 170 of the eruption, near V = 11, the orbital signal reappeared with an amplitude of 0.005 mag. It then gradually strengthened to its normal 0.08 mag amplitude, as the star declined to its "quiescent" magnitude of 15.7. During the ~1 year of invisibility and low amplitude, the orbital signal had increased in period by 0.0054(7)%. This is probably a measure of the mass ejected in the nova outburst. For a plausible choice of binary parameters, that mass is at least 3×10 -5 M ☉ , and probably more. This represents >300 years of accretion at the pre-outburst rate, but the time between outbursts was only 45 years. Thus the erupting white dwarf seems to have ejected at least 6× more mass than it accreted. If this eruption is typical, the white dwarf must be eroding, rather than growing, in mass. Unless the present series of eruptions is a short-lived episode, the binary dynamics appear to be a mutual suicide pact between the eroding white dwarf and the low-mass secondary, excited and rapidly whittled down, probably by the white dwarf's EUV radiation. This could be a major channel by which short-period cataclysmic variables are rapidly removed from the population -by evaporating the secondary.

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“…However, the very flat radio spectra -α = 0.14 ± 0.04 on day 62.3 and α = 0.16 ± 0.04 on day 81.1 -are inconsistent with optically thick thermal emission. Therefore, if the radio-flare emission was thermal, the emitting material most likely had a physical temperature significantly greater than 10 5 K. Unshocked ejecta, however, are typically observed to have T ∼ 10 4 K (Seaquist & Palimaka 1977;Hjellming et al 1979;Nelson et al 2014;Weston et al 2016). Moreover, Cunningham et al (2015) argued on theoretical grounds that photoionziation heating of ejecta by the residual burning of nuclear fuel in a shell on the surface of the WD leads to temperatures of at most a few times 10 4 K, even for photoionization by hot, luminous high-mass WDs (T. Cunningham, private communication; see also Table 2 of Cunningham et al 2015).…”

Section: Evidence For Non-thermal Emissionmentioning

confidence: 99%

“…These shocks can be caused by collisions with pre-existing circumstellar material (eg., V407 Cyg, V745 Sco, and RS Oph; Bode et al 2006;Das et al 2006; interactions between multiple flows from the same eruption (eg., V959 Mon, T Pyx, V382 Vel; Mukai & Ishida 2001;Nelson et al 2014;. Radio monitoring of novae, especially when combined with observations at other frequencies, provides a powerful tool for understanding the evolution of nova eruptions and examining shocks within the ejecta.…”

Section: Introductionmentioning

confidence: 99%

Shock-powered radio emission from V5589 Sagittarii (Nova Sgr 2012 #1)

Weston

Sokoloski

Chomiuk

et al. 2016

Mon. Not. R. Astron. Soc.

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Since the Fermi discovery of γ-rays from novae, one of the biggest questions in the field has been how novae generate such high-energy emission. Shocks must be a fundamental ingredient. Six months of radio observations of the 2012 nova V5589 Sgr with the VLA and 15 weeks of X-ray observations with Swift/XRT show that the radio emission consisted of: 1) a shock-powered, non-thermal flare; and 2) weak thermal emission from 10 −5 M of freely expanding, photoionized ejecta. Absorption features in the optical spectrum and the peak optical brightness suggest that V5589 Sgr lies 4 kpc away (3.2-4.6 kpc). The shock-powered flare dominated the radio light curve at low frequencies before day 100. The spectral evolution of the radio flare, its high radio brightness temperature, the presence of unusually hard (kT x > 33 keV) X-rays, and the ratio of radio to X-ray flux near radio maximum all support the conclusions that the flare was shock-powered and non-thermal. Unlike most other novae with strong shock-powered radio emission, V5589 Sgr is not embedded in the wind of a redgiant companion. Based on the similar inclinations and optical line profiles of V5589 Sgr and V959 Mon, we propose that shocks in V5589 Sgr formed from collisions between a slow flow with an equatorial density enhancement and a subsequent faster flow. We speculate that the relatively high speed and low mass of the ejecta led to the unusual radio emission from V5589 Sgr, and perhaps also to the non-detection of γ-rays.

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The 2011 Outburst of Recurrent Nova T Pyx: Radio Observations Reveal the Ejecta Mass and Hint at Complex Mass Loss

Cited by 53 publications

References 52 publications

A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

A Detailed Observational Analysis of V1324 Sco, the Most Gamma-Ray-luminous Classical Nova to Date

T Pyxidis: death by a thousand novae

Shock-powered radio emission from V5589 Sagittarii (Nova Sgr 2012 #1)

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