X-rays from solar system objects

Bhardwaj, Anil; Elsner, Ronald F.; Gladstone, G. Randall; Cravens, T. E.; Lisse, C. M.; Dennerl, K.; Branduardi‐Raymont, G.; Wargelin, Bradford J.; Waite, J. H.; Robertson, I. P.; Østgaard, Nikolai; Beiersdörfer, P.; Snowden, S. L.; Kharchenko, V.

doi:10.1016/j.pss.2006.11.009

Cited by 136 publications

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References 234 publications

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“…This was a time of quiet solar wind conditions, and yet the UV aurora was seen to be very variable; the measured UV power at the time of the XMM-Newton observation varied between 3.3 and 8.0 GW Clarke et al (2005). (d) Bhardwaj et al (2007). (e) This paper.…”

Section: The Origin Of the Rings X-ray Emissionmentioning

confidence: 96%

“…In any case, taking these estimates together with the vaste distances from Earth of these two planets excludes the possibility of detecting their X-ray auroral emissions with current instruments. Indeed Bhardwaj et al (2007) report an unsuccessful attempt by Chandra to detect X-rays from Uranus in August 2002. These authors also suggest that Uranus and Neptune, as well as Saturn's moon Titan, are likely to shine in X-rays, both by particle precipitation in the magnetosphere, and by scattering of solar X-rays.…”

Section: The Origin Of the Rings X-ray Emissionmentioning

confidence: 99%

“…For planets with a significant magnetic field, namely Jupiter and the Earth, the X-ray emission has been found to separate essentially into two components: a high-latitude auroral one, and a low-latitude disk component, which has different spectral properties, relating it to solar X-rays (Maurellis et al 2000;Gladstone et al 2002;Branduardi-Raymont et al 2004;Bhardwaj et al 2005c;Elsner et al 2005;Branduardi-Raymont et al 2007a,b;Bhardwaj et al 2007). Naively we would expect to observe a similar dichotomy on Saturn, given the strength of its magnetic field and its fast rotation (as for Jupiter) and its powerful UV aurorae (Gérard et al 2004(Gérard et al , 2005, but this is not the case.…”

Section: Introductionmentioning

confidence: 99%

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X-rays from Saturn: a study withXMM-NewtonandChandraover the years 2002–05

Branduardi‐Raymont¹,

Bhardwaj²,

Elsner³

et al. 2010

A&A

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Aims. We approach the study of Saturn and its environment in a novel way using X-ray data, by making a systematic and uniform spectral analysis of all the X-ray observations of the planet to date. Methods. We present the results of the two most recent (2005) XMM-Newton observations of Saturn together with the re-analysis of an earlier (2002) observation from the XMM-Newton archive and of three Chandra observations in 2003 and 2004. While the XMM-Newton telescope resolution does not enable us to resolve spatially the contributions of the planet's disk and rings to the X-ray flux, we can estimate their strengths and their evolution over the years from spectral analysis, and compare them with those observed with Chandra. Results. The spectrum of the X-ray emission is well fitted by an optically thin coronal model with an average temperature of 0.5 keV. The addition of a fluorescent oxygen emission line at ∼0.53 keV improves the fits significantly. In accordance with earlier reports, we interpret the coronal component as emission from the planetary disk, produced by the scattering of solar X-rays in Saturn's upper atmosphere, and the line as originating from the Saturnian rings. The strength of the disk X-ray emission is seen to decrease over the period [2002][2003][2004][2005], following the decay of solar activity towards the current minimum in the solar cycle. By comparing the relative fluxes of the disk X-ray emission and the oxygen line, we suggest that the line strength does not vary over the years in the same fashion as the disk flux. We consider possible alternatives for the origin of the line. The connection between solar activity and the strength of Saturn's disk X-ray emission is investigated and compared with that of Jupiter. We also discuss the apparent lack of X-ray aurorae on Saturn; by comparing the planet's parameters relevant to aurora production with those of Jupiter we conclude that Saturnian X-ray aurorae are likely to have gone undetected because they are below the sensitivity threshold of current Earth-bound observatories. A similar comparison for Uranus and Neptune leads to the same disappointing conclusion, which is likely to hold true also with the planned next generation International X-ray Observatory. The next step in advancing this research can only be realised with in-situ X-ray observations at the planets.

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Section: The Origin Of the Rings X-ray Emissionmentioning

confidence: 96%

Section: The Origin Of the Rings X-ray Emissionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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X-rays from Saturn: a study withXMM-NewtonandChandraover the years 2002–05

Branduardi‐Raymont¹,

Bhardwaj²,

Elsner³

et al. 2010

A&A

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“…[2]), and one now understands that the main emission mechanism for comets is charge exchange. Several planets in the solar system have been observed with Chandra producing discoveries such as the time-variable X-ray flux from Jupiter that originates, not from the UV auroral zone as had been expected, but from higher latitudes near Jupiter's pole -i.e.…”

Section: Scientific Resultsmentioning

confidence: 99%

Chandra: Ten Years of Amazing Science with a Great Observatory

Weisskopf¹,

Comastri²,

Angelini³

et al. 2010

AIP Conference Proceedings

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Abstract. We review briefly review the history of the development of the Chandra X-Ray Observatory, highlighting certain details that many attendees of this Conference might not be aware of. We then present a selection of scientific highlights of the first 10 years of this remarkable and unique mission.. Keywords: PACS: <95> It is sobering that there are scientists at this conference who were not born when the Observatory was first conceived. The concept was first articulated in a research proposal that Riccardo Giacconi colleagues wrote in 1963 only 9 months after their discovery of Sco X-1, the first extra-solar X-Ray source, and what came to be known as the "diffuse X-Ray background". The centerpiece of this insightful proposal was a ≈ 1 meter diameter, 10-meter focal length, grazing-incidence X-Ray telescope with effective area and angular resolution sized to determine the nature of the unresolved background.In 1976 Riccardo and Co-Principal Investigator Harvey Tananbaum submitted an unsolicited proposal "For the Study of the 1.2 Meter X-Ray Telescope National Observatory" which required arcsecond-scale angular resolution to meet the proposed scientific objectives. The proposal drew sufficient attention at NASA HQ to cause it to initiate a competition amongst the NASA Centers establishing where such a mission might best be accomplished. Marshall teamed with the Smithsonian Astrophysical Observatory (SAO) in vying for, and winning, the management of the mission which, shortly after the assignment, was named the Advanced X-ray Astrophysics Facility (AXAF).

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“…These observatories have clarified the nature of X-ray radiation from comets 3 , collected a wealth of data on the nature of X-ray emission from stars of all ages 4,5 , and used spectra and images of supernova shock waves to confirm the basic gas dynamical model 6,7 of these objects. They have resolved into discrete point sources the diffuse emission from the plane of the Galaxy 8 , as well as the diffuse extragalactic X-ray background 9 .…”

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confidence: 99%

The first decade of science with Chandra and XMM-Newton

2010

Phys. Today

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NASA's Chandra X-ray Observatory and the ESA's X-ray Multi-Mirror Mission (XMM-Newton) made their first observations ten years ago. The complementary capabilities of these observatories allow us to make high-resolution images and precisely measure the energy of cosmic X-rays. Less than 50 years after the first detection of an extrasolar X-ray source, these observatories have achieved an increase in sensitivity comparable to going from naked-eye observations to the most powerful optical telescopes over the past 400 years. We highlight some of the many discoveries made by Chandra and XMM-Newton that have transformed twenty-first century astronomy.T ypically, cosmic X-rays are produced in extreme conditionsfrom intense gravitational and magnetic fields around neutron stars and black holes, to intergalactic shocks in clusters of galaxies. Chandra 1 and XMM-Newton 2 have probed the space-time geometry around black holes, unveiled the importance of accreting supermassive black holes in the evolution of the most massive galaxies, demonstrated in a unique manner that dark matter exists, and confirmed the existence of dark energy. They have also tracked the production and dispersal of heavy elements by supernovae and measured the magnitude and rate of flaring of young Sun-like stars. Table 1 gives a subjectiveand by-no-means complete listof significant discoveries made using these observatories.With an order-of-magnitude or more improvement in spectral and spatial resolution and sensitivity, Chandra and XMM-Newton have shed light on known problems, as well as opened new areas of research. These observatories have clarified the nature of X-ray radiation from comets 3 , collected a wealth of data on the nature of X-ray emission from stars of all ages 4,5 , and used spectra and images of supernova shock waves to confirm the basic gas dynamical model 6,7 of these objects. They have resolved into discrete point sources the diffuse emission from the plane of the Galaxy 8 , as well as the diffuse extragalactic X-ray background 9 . They have discovered hundreds of supermassive black holes at the centres of galaxies and for many of those obtained high-resolution spectra that have Comets Established charge-exchange as mechanism for X-ray emission. Individual stars Measured densities, temperatures and composition of hot plasmas, testing models for stellar evolution, X-ray emission from stellar coronae, and stellar winds. Star formation and star-forming regions Discovered X-ray emission from gas accreting onto stellar surfaces and influenced by magnetic fields; detected giant flares from young stars, with implications for planet formation. SupernovaeEstablished that Kepler's supernova was a thermonuclear event. Supernova remnants (SNRs) Discovered a central compact object in the Cas A SNR and traced the distribution of elements indicating turbulent mixing along with an aspherical explosion. Imaged forward and reverse shock waves in several SNR, with implications for the acceleration of cosmic rays. Pulsar wind nebulaeResolved jets ...

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X-rays from solar system objects

Cited by 136 publications

References 234 publications

X-rays from Saturn: a study withXMM-NewtonandChandraover the years 2002–05

X-rays from Saturn: a study withXMM-NewtonandChandraover the years 2002–05

Chandra: Ten Years of Amazing Science with a Great Observatory

The first decade of science with Chandra and XMM-Newton

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