Stewart P S Eyres

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RS Ophiuchi began its latest outburst on 2006 February 12. Previous outbursts have indicated that high velocity ejecta interact with a pre-existing red giant wind, setting up shock systems analogous to those seen in Supernova Remnants. However, in the previous outburst in 1985, X-ray observations did not commence until 55 days after the initial explosion.(More)
We report ISO observations of globular clusters, from which we derive new upper limits on the masses of dust therein. Our observations do not confirm the claimed detection of dust in 47 Tuc by Gillett et al. (1988) and our limits generally support previous conclusions that globular clusters are deficient in intra-cluster dust grains. We find that sputtering(More)
  • Ya V Pavlenko, T R Geballe, +4 authors L A Yakovina
  • 2004
We present the results of our analysis of a high resolution (R ≃ 30000) infrared spectrum of V4334 Sgr (Sakurai’s Object) around the first overtone CO bands, obtained in 1998 July. The CO and CO bands are well-resolved, and we compute synthetic hydrogen-deficient model atmosphere spectra to determine the C/C ratio. We find C/C ≃ 4± 1, consistent with the(More)
Aims. We report spectra of the overtone and fundamental bands of CO in the eruptive variable V838 Mon, which trace the recent evolution of the star and allow its ejecta to be characterized. Methods. The data were obtained at the United Kingdom Infrared Telescope on fourteen nights from 2002 January, shortly after the first outburst of the star, to 2006(More)
The results of a HST/WFPC2 snapshot imaging survey of selected symbiotic stars in 1999/2000 are presented. Seven sources – HD 149427 (PC 11), PU Vul, RT Ser, He2−104 (Southern Crab), V1329 Cyg (HBV 475), V417 Cen, AS 201 – were observed in filters F218W (ultraviolet continuum), F502N ([Oiii]λλ 4959, 5007) and F656N (Hαλ 6563); an eighth source, RS Oph, was(More)
We report Hubble Space Telescope imaging obtained 155 days after the 2006 outburst of RS Ophiuchi. We detect extended emission in both [O iii] λ5007 Å and [Nev] λ3426 Å lines. In both lines, the remnant has a double ring structure. The E-W orientation and total extent of these structures (580 ± 50 AU at d = 1.6kpc) is consistent with that expected due to(More)
After a hot white dwarf ceases its nuclear burning, its helium may briefly and explosively reignite. This causes the star to evolve back into a cool giant, whereupon it experiences renewed mass ejection before reheating. A reignition event of this kind was observed in 1996 in V4334 Sgr (Sakurai's object). Its temperature decrease was 100 times the predicted(More)
Nova outbursts take place in binary star systems comprising a white dwarf and either a low-mass Sun-like star or, as in the case of the recurrent nova RS Ophiuchi, a red giant. Although the cause of these outbursts is known to be thermonuclear explosion of matter transferred from the companion onto the surface of the white dwarf, models of the previous(More)
The evolution of the 2006 outburst of the recurrent nova RS Ophiuchi was followed with 12 Xray grating observations with Chandra and XMM-Newton. We present detailed spectral analyses using two independent approaches. From the best dataset, taken on day 13.8 after outburst, we reconstruct the temperature distribution and derive elemental abundances. We find(More)
Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10(-4) solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly(More)