Journal Article

Near-infrared observations of nova V574 Puppis (2004)

Sachindra Naik, D. P. K. Banerjee, N. M. Ashok and R. K. Das

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 404, issue 1, pages 367-375
Published in print May 2010 | ISSN: 0035-8711
Published online April 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.16292.x
Near-infrared observations of nova V574 Puppis (2004)

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We present results obtained from extensive near-infrared spectroscopic and photometric observations of nova V574 Pup during its 2004 outburst. The observations were obtained over 4 months, starting from 2004 November 25 (4 d after the nova outburst) to 2005 March 20. The near-infrared JHK light curve is presented – it shows no evidence of the fact that dust formation has occurred during our observations. In the early decline phase, the JHK spectra of the nova are dominated by emission lines of hydrogen Brackett and Paschen series, O i, C i and He i. We also detect the fairly uncommon Fe ii line at 1.6872 μm in the early part of our observations. The strengths of the He i lines at 1.0830 and 2.0585 μm are found to become very strong towards the end of the observations indicating a progression towards higher excitation conditions in the nova ejecta. The width of the emission lines does not show any significant change during the course of our observations. The slope of the continuum spectrum was found to have a λ−2.75 dependence in the early stages which gradually becomes flatter with time and changes to a free–free spectral dependence towards the later stages. Recombination analysis of the H i lines shows deviations from case B conditions during the initial stages. However, towards the end of our observations, the line strengths are well simulated with case B model values with electron density ne= 109−10 cm−3 and a temperature equal to 104 K. Based on our distance estimate to the nova of 5.5 kpc and the observed free–free continuum emission in the later part of the observations, we estimate the ionized mass of the ejecta to be between 10−5 and 10−6 M.

Keywords: techniques: spectroscopic; stars: individual: V574 Pup; novae, cataclysmic variables; infrared: stars

Journal Article.  5141 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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