Variable Hard X-Ray Emission from the Central Star of the Eskimo Nebula

Guerrero, M. A.; Toalá, J. A.; Chu, You‐Hua

doi:10.3847/1538-4357/ab4256

Cited by 10 publications

(5 citation statements)

References 60 publications

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“…The low luminosity 10 26 erg s −1 (and thus accretion rate) and plasma temperature ≈0.17-0.7 keV of the X-ray emission from G 29-38 is very different to those of systems with high accretion rates such as symbiotic stars and CVs (L X 10 31 erg s −1 and T X 1 keV; see Figure 3 in Guerrero et al 2019). The X-ray luminosity is also below that of putative single WDs with hard X-ray emission, which may still present plasmas at similar temperatures (L X ∼ 5 × 10 29 -5 × 10 31 erg s −1 and T X ∼ 0.1-1.5 keV; Chu et al 2021;S.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 90%

XMM-Newton Detection of X-Ray Emission from the Metal-polluted White Dwarf G 29-38

Estrada-Dorado¹,

Guerrero

Toalá³

et al. 2023

ApJL

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A recent analysis of Chandra X-ray data of the metal-polluted white dwarf G 29-38 has revealed X-ray emission that can be attributed to the accretion of debris from a planetary body. In the light of this detection we revisit here archival XMM-Newton observations of G 29-38 from which only an upper limit was derived in the past due to the presence of a relatively bright nearby X-ray source. An analysis of these data in multiple energy bands allows disentangling of the X-ray emission at the location of G 29-38 from that of the nearby source. The similar spectral properties of the source in the XMM-Newton and Chandra observations and their spatial shift, consistent with the proper motion of G 29-38 between these observations, strengthen the origin of the X-ray emission from G 29-38. The X-ray luminosities from both observations are consistent within the 1σ uncertainties, so too are the best-fit plasma temperatures. Although the count number is small, there is tantalizing evidence for line emission in the 0.7–0.8 keV energy band from an optically thin hot plasma. The most likely candidate for this line emission would be the Fe complex at 16 Å.

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Section: Discussion and Concluding Remarksmentioning

confidence: 90%

XMM-Newton Detection of X-Ray Emission from the Metal-polluted White Dwarf G 29-38

Estrada-Dorado¹,

Guerrero

Toalá³

et al. 2023

ApJL

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“…Finally, it is worth noting that the central star of NGC 2392 has recently been recognized to be in a binary system (Miszalski et al 2019). Its orbital period is yet unsettled, as periodic radial velocity variations of 3 hours (Prinja & Urbaneja 2014) and 1.9 days (Miszalski et al 2019) and a hard X-ray emission modulation of 6 hours (Guerrero et al 2019) have been reported. The companion of the central star of NGC 2392 has been proposed to be a hot white dwarf as its effective temperature 43,000 K (Méndez et al 2012) cannot explain its high nebular excitation, being notably discrepant from the higher He ii Zanstra temperature (Heap 1977;Pottasch et al 2008;Miszalski et al 2019).…”

Section: Ngc 2392 In the Ecosystem Of Pnementioning

confidence: 99%

Tomography of the unique on-going jet in the planetary nebula NGC 2392

Guerrero,

Cazzoli,

Rechy-Garcia

et al. 2021

Preprint

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Jets (fast collimated outflows) are claimed to be the main shaping agent of the most asymmetric planetary nebula (PNe) as they impinge on the circumstellar material at late stages of the asymptotic giant branch (AGB) phase. The first jet detected in a PN was that of NGC 2392, yet there is no available image because its low surface brightness contrast with the bright nebular emission. Here we take advantage from the tomographic capabilities of GTC MEGARA high-dispersion integral field spectroscopic observations of the jet in NGC 2392 to gain unprecedented details of its morphology and kinematics. The jet of NGC 2392 is found to emanate from the central star, break through the walls of the inner shell of this iconic PN and extend outside the nebula's outermost regions with an Sshaped morphology suggestive of precession. At odds with the fossil jets found in mature PNe, the jet in NGC 2392 is currently being collimated and launched. The high nebular excitation of NGC 2392, which implies a He ++ /He ionization fraction too high to be attributed to the known effective temperature of the star, has been proposed in the past to hint at the presence of a hot white dwarf companion. In conjunction with the hard X-ray emission from the central star, the present-day jet collimation would support the presence of such a double-degenerate system where one component undergoes accretion from a remnant circumbinary disk of the common envelope phase.

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“…The hard X-ray emission from the CSPN of the Eskimo Nebula has been found to be variable with a period ≃6 hours [10]. This X-ray emission might be attributed to accretion of material from the CSPN wind onto a white dwarf companion, and thus the observed period can be assigned either to the orbital period of the companion or to the rotation of an accretion disk around it.…”

Section: X-ray Variability Studiesmentioning

confidence: 99%

X-ray Observations of Planetary Nebulae since WORKPLANS I and Beyond

Guerrero

2020

Galaxies

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Planetary nebulae (PNe) were expected to be filled with hot pressurized gas driving their expansion. ROSAT hinted at the presence of diffuse X-ray emission from these hot bubbles and detected the first sources of hard X-ray emission from their central stars, but it was not until the advent of Chandra and XMM-Newton that we became able to study in detail their occurrence and physical properties. Here I review the progress in the X-ray observations of PNe since the first WORKshop for PLAnetary Nebulae observationS (WORKPLANS) and present the perspective for future X-ray missions with particular emphasis on eROSITA.

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Variable Hard X-Ray Emission from the Central Star of the Eskimo Nebula

Cited by 10 publications

References 60 publications

XMM-Newton Detection of X-Ray Emission from the Metal-polluted White Dwarf G 29-38

XMM-Newton Detection of X-Ray Emission from the Metal-polluted White Dwarf G 29-38

Tomography of the unique on-going jet in the planetary nebula NGC 2392

X-ray Observations of Planetary Nebulae since WORKPLANS I and Beyond

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