The first resolved and detected classical nova shell in X-rays: The shell of Nova Persei 1901

We present the ROSAT High-Resolution Imager data of the first resolved and detected classical nova shell in the X-ray wavelengths: the shell of Nova Persei 1901. We find that the X-ray nebula is composed of knots/clumps and has an elliptical shape with a total count rate of about 0.01 +/- 0.001 counts s(-1). We estimate that the spectrum is of thermal origin with a luminosity of similar to 8.0 x 10(31) ergs s(-1) and an X-ray temperature of similar to 2.0 x 10(6) K in the 0.1-2.4 keV energy range. The knots/clumps are a result of fragmentation and condensation in the postshock region. The estimated electron density in the knots/clumps is about 10.0 cm(-3) less than or equal to n(e) less than or equal to 70.0 cm(-3). We suggest that the detected X-ray nebula could also be the reverse shock zone. This detection sheds light into one of the most poorly understood stages of the classical nova evolution

The first resolved and detected classical nova shell in X-rays in comparison with the ROSAT detections of hard X-ray emission from classical nova in outburst

We present the ROSAT High Resolution Imager (HRI) data of the first resolved and detected classical nova shell in the X-ray wavelengths : The shell of Nova Persei (1901). We find that the shell is composed of knots and has an elliptical shape. The surface brightness is about 703.4+/-54.5 counts arcmin(-2). We estimate that the spectrum is of thermal origin with a luminosity of 8.0x10(31) erg s(-1) and an X-ray temperature of similar to 2.0x10(6) K in the 0.1-2.4 keV energy range. The knots are most likely a result of fragmentation and condensation in the post-shock region. This detection sheds some light into one of the most poorly understood stages of classical nova evolution. (C) 2000 COSPAR. Published by Elsevier Science Ltd

Abundance anomalies in CP Crucis (Nova Crux 1996)

We present spectroscopic observations of the classical nova CP Crucis (Nova Crux 1996) obtained with the Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) and the Anglo-Australian Telescope using both the Infrared Imaging Spectrograph and the Royal Greenwich Observatory Spectrograph. From the expansion parallax, we find that CP Crucis lies at a distance of 2.6 ± 0.5 kpc and reached a maximum M_{V} of -8.7 at 0.96 days after discovery. We find abundance enhancements versus solar by mass of 75, 17, and 27 for N, O, and Ne, respectively. Additionally, we constrain the Mg abundance in the ejecta to be approximately solar. Abundance analysis suggests CP Crucis is an old Population I binary system. Combining the strong N and Ne abundances with the relatively low Mg abundance and a Ne/O ratio of 0.5, we propose that CP Crucis is an example of the "missing link" between CO and ONeMg novae

Infrared space observatory short wavelength spectrometer observations of V1425 Aquilae (Nova Aquila 1995)

We present observations of the classical nova V1425 Aquilae (Nova Aquila 1995) with the Infrared Space Observatory's (ISO) Short Wavelength Spectrometer, the Isaac Newton Telescope's Intermediate Dispersion Spectrograph, and the International Ultraviolet Explorer's Short-Wavelength Primary Spectrograph. Analysis of He II (1640 Å) development constrains the white dwarf turnoff to ~400 days after outburst. Photoionization modeling of the optical and ISO spectra obtained during the late nebular phase constrains the mass of the ejecta between 2.5–4.2 × 10-5 M⊙. This modeling also suggests C and O in the ejecta were enhanced by a factor of ~9, and N was enhanced by a factor of ~100 with respect to solar, while Ne was only slightly enhanced. Based upon these analyses, we determine that the white dwarf in the V1425 Aql system has a CO composition and is at a distance of 3.0 ± 0.4 kpc