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Post Info TOPIC: KT Eridani


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RE: KT Eridani
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Title: Nova KT Eri 2009: Infrared studies of a very fast and small amplitude He/N nova
Authors: Ashish Raj, D.P.K. Banerjee, N.M. Ashok

We present near-infrared spectroscopic and photometric observations of the nova KT Eridani taken during the first 100 days following its discovery in 2009 November. The JHK spectra of the object have been taken from the Mount Abu Infrared Observatory using the Near-Infrared Imager/Spectrometer. The spectra, typical of the He/N class novae, show strong He I emission lines together with H I and O I emission features. The H I, Pa-beta and Br-gamma spectral lines and the He I line at 2.0581 micron show broad wings with a relatively narrow central component. The broad wings extend to 1900 km/s while the central component has FWHM of 2100 km/s. The V and near-infrared JHK light curves show an additional small amplitude outburst near 40 days after optical maximum. The distance to the nova d = 6.3 ▒ 0.1 kpc is derived using the MMRD relation and the estimated value of t2 = 5.7 ▒ 0.3 days. The small value of t2 places KT Eri in the class of very fast novae. Using the value of the distance to the nova d, we estimate the height of the nova to be z = 3.3 ▒ 0.1 kpc below the galactic plane. We have also calculated the upper limit for the ejecta mass for KT Eri to be in the range 2.4-7.4 x 10^(-5) solar masses. Kinematic evidence is presented from the shape of the line profiles for a possible bipolar flow. We analyse the temporal evolution of the continuum and also discuss the possibility of KT Eri being a recurrent nova.

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Nova Eridani 2009
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Title: Morpho-Kinematical Modelling of Nova Eridani 2009 (KT Eri)
Authors: V. A. R. M. Ribeiro (1), M. F. Bode (2), M. J. Darnley (2), R. M. Barnsley (2), U. Munari (3 and 4), D. J. Harman (2) ((1) Astrophysics, Cosmology and Gravity Centre, Department of Astronomy, University of Cape Town, (2) Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, CH41 1LD, UK, (3) INAF Astronomical Observatory of Padova, (4) ANS Collaboration)

Modelling the morphology of a nova outburst provides valuable information on the shaping mechanism in operation at early stages following the outburst. We performed morpho-kinematical studies, using shape, of the evolution of the H\alpha\ line profile following the outburst of the nova KT Eridani. We applied a series of geometries in order to determine the morphology of the system. The best fit morphology was that of a dumbbell structure with a ratio between the major to minor axis of 4:1, with an inclination angle of 58^{+6}_{-7} degrees and a maximum expansion velocity of 2800 ▒200 km/s. Although, we found that it is possible to define the overall structure of the system, the radial density profile of the ejecta is much more difficult to disentangle. Furthermore, morphology implied here may also be consistent with the presence of an evolved secondary as suggested by various authors.

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RE: KT Eridani
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Title: Observational Report of the Classical Nova KT Eridani
Authors: Kazuyoshi Imamura, Kenji Tanabe

A report on the spectroscopic and multi-colour photometric observations of high galactic latitude classical nova KT Eridani (Nova Eridani 2009) is presented. After 12.2 days from maximum light, broad and prominent emission lines of Balmer series, He I, He II, N II, N III and O I can be seen on the spectra. The FWHM of H \alpha line yields an expansion velocity of approximately 3400 km s^{-1}. After 279.4 days from maximum light, we can see prominent emission lines of He II and [O III] on the spectrum. Among them, [O III] (4959, 5007) lines show multiple peaks. From the obtained light curve, KT Eri is classified to be a very fast nova, with a decline rate by two magnitude of 6.2 ▒0.3 days and three of 14.3 ▒0.7 days. We tried to estimate the absolute magnitude (M_V) using the Maximum Magnitude versus Rate of Decline relationship and distance of KT Eri. The calculated M_V is approximately -9. Accordingly, the distance and galactic height are approximately 7 kpc and 4 kpc, respectively. Hence, KT Eri is concluded to be located outside of the galactic disk.

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Title: Historical light curve and search for previous outbursts of Nova KT Eridani (2009)
Authors: R. Jurdana-Sepic, V. A. R. M. Ribeiro, M. J. Darnley, U. Munari, M. F. Bode

Context. Nova Eridani (2009) caught the eye of the nova community due to its fast decline from maximum, which was initially missed, and its subsequent development in the radio and X-ray wavelengths. This system also exhibits properties similar to those of the much smaller class of recurrent novae; themselves potential progenitors of Type Ia Supernovae.
Aims. We aim to determine the nature and physical parameters of the KT Eri progenitor system.
Methods. We searched the Harvard College Observatory archive plates for the progenitor of KT Eri to determine the nature of the system, particularly the evolutionary stage of the secondary. We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale. Furthermore, by comparing the colours of the quiescent system on a colour-magnitude diagram we may infer the nature of the secondary star.
Results. We identified the progenitor system of KT Eri and measured a quiescent magnitude of < B >= 14.7 ▒0.4. No previous outburst was found. However, we suggest that if the nova is recurrent it should be on a timescale of centuries. We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary. The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in, or ascending, the Red Giant Branch. A second period is evident at 376 days which has a sinusoidal like light curve. Furthermore, the outburst amplitude of ~ 9 magnitudes is inconsistent with those expected for fast classical novae (~ 17 magnitudes) which may lend further support for an evolved secondary.

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Posts: 131433
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KT Eridanus
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Nova Eridanus 2009 is now officially KT Eridanus.

IAUC 9098(Subscription)


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Posts: 131433
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RE: Possible nova in Eridanus
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noverie4.gif
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Credit: M. Fujii


Observations taken on theá obtained on the 26th November, 2009, show the Spectra a typical He/N-class nova
The nova may have reached magnitude 5.6 on the 15thá November, 2009.

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Nova in Eridanus
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Progenitor Star

PrenovaEridanb.jpg
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RE: Possible nova in Eridanus
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novaeri1.gif

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Posts: 131433
Date:
Nova in Eridanus
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noveran-1.gif
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Posts: 131433
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RE: Possible nova in Eridanus
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The possible nova was discoveredá by K. Itagaki (Japan) in the 25th November, 2009.

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