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Post Info TOPIC: Nova Del 2013
Blobrana


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Posts: 131433
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V339 Delphini
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Title: Rise and fall of the dust shell of the classical nova V339 Delphini
Author: A. Evans (Keele University, UK), D. P. K. Banerjee (PRL, Ahmedabad, India), R. D. Gehrz (Minnesota Institute for Astrophysics, University of Minnesota), V. Joshi, N. M. Ashok (PRL), V. A. R. M. Ribeiro (Radboud University, Botswana International University of Science and Technology), M. J. Darnley (LJMU), C. E. Woodward (Minnesota), D. Sand (Texas Tech University), G. H. Marion (University of Texas at Austin), T. R. Diamond (NASA Goddard SFC), S. P. S. Eyres (Univ. Central Lancs), R. M. Wagner (Ohio State University), L. A. Helton (USRA-SOFIA Science Center), S. Starrfield (ASU), D. P. Shenoy (Minnesota), J. Krautter (Heidelberg), W. D. Vacca (USRA-SOFIA Science Center), M. T. Rushton (Astronomical Institute of the Romanian Academy)

We present infrared spectroscopy of the classical nova V339 Delphini, obtained over a ~2 year period. The infrared emission lines were initially symmetrical, with HWHM velocities of 525 km s^-1. In later (t \gtrsim 77days, where t is the time from outburst) spectra however, the lines displayed a distinct asymmetry, with a much stronger blue wing, possibly due to obscuration of the receding component by dust. Dust formation commenced at ~ day 34.75 at a condensation temperature of 1480±20K, consistent with graphitic carbon. Thereafter the dust temperature declined with time as T_d \propto t^-0.346, also consistent with graphitic carbon. The mass of dust initially rose, as a result of an increase in grain size and/or number, peaked at ~ day 100, and then declined precipitously. This decline was most likely caused by grain shattering due to electrostatic stress after the dust was exposed to X-radiation. An Appendix summarises Planck Means for carbon, and the determination of grain mass and radius for a carbon dust shell.

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Blobrana


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RE: Nova Del 2013
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Title: The Expanding Fireball of Nova Delphini 2013
Author: G. H. Schaefer, T. ten Brummelaar, D. R. Gies, C. D. Farrington, B. Kloppenborg, O. Chesneau, J. D. Monnier, S. T. Ridgway, N. Scott, I. Tallon-Bosc, H. A. McAlister, T. Boyajian, V. Maestro, D. Mourard, A. Meilland, N. Nardetto, P. Stee, J. Sturmann, N. Vargas, F. Baron, M. Ireland, E. K. Baines, X. Che, J. Jones, N. D. Richardson, R. M. Roettenbacher, L. Sturmann, N. H. Turner, P. Tuthill, G. van Belle, K. von Braun, R. T. Zavala, D. P. K. Banerjee, N. M. Ashok, V. Joshi, J. Becker, P. S. Muirhead

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting from one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 ± 0.59 kpc from the Sun.

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Blobrana


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Title: Early evolution of the extraordinary Nova Del 2013 (V339 Del)
Author: A. Skopal, H. Drechsel, T. N. Tarasova, T. Kato, M. Fujii, F. Teyssier, O. Garde, J. Guarro, J. Edlin, C. Buil, D. Antao, J. N. Terry, T. Lemoult, S. Charbonnel, T. Bohlsen, A. Favaro, K. Graham

We determine the temporal evolution of the luminosity L(WD), radius R(WD) and effective temperature Teff of the white dwarf (WD) pseudophotosphere of V339 Del from its discovery to around day 40. Another main objective was studying the ionization structure of the ejecta. These aims were achieved by modelling the optical/near-IR spectral energy distribution (SED) using low-resolution spectroscopy (3500 - 9200 A), UBVRcIc and JHKLM photometry. During the fireball stage (Aug. 14.8 - 19.9, 2013), Teff was in the range of 6000 - 12000 K, R(WD) was expanding non-uniformly in time from around 66 to around 300 (d/3 kpc) R(Sun), and L(WD) was super-Eddington, but not constant. After the fireball stage, a large emission measure of 1.0-2.0E+62 (d/3 kpc)**2 cm**(-3) constrained the lower limit of L(WD) to be well above the super-Eddington value. The evolution of the H-alpha line and mainly the transient emergence of the Raman-scattered O VI 1032 A line suggested a biconical ionization structure of the ejecta with a disk-like H I region persisting around the WD until its total ionization, around day 40. It is evident that the nova was not evolving according to the current theoretical prediction. The unusual non-spherically symmetric ejecta of nova V339 Del and its extreme physical conditions and evolution during and after the fireball stage represent interesting new challenges for the theoretical modelling of the nova phenomenon.

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Blobrana


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Posts: 131433
Date:
V339 Delphini
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ATel 5967: Swift observations of the fading of V339 Del. 

 



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Blobrana


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Posts: 131433
Date:
Nova Delphini 2013
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Title: Pre-outburst observations of Nova Del 2013 from Pan-STARRS 1
Author: N.R. Deacon (1), D.W. Hoard (1), E.A. Magnier (2), Y.S. Jadhav (1,3), M. Huber (2), K.C. Chambers (2), H. Flewelling (2), K.W. Hodapp (4), N. Kaiser (2), R.P. Kudritzki (2), N. Metcalfe (5), C. Waters (2) ((1) MPIA, (2) IfA, University of Hawaii at Manoa), (3) Ohio University, (4)IfA, University of Hawaii at Hilo, (5) Durham University)

Nova Delphini 2013 was identified on the 14th of August 2013 and eventually rose to be a naked eye object. We sought to study the behaviour of the object in the run-up to outburst and to compare it to the pre-outburst photometric characteristics of other novae. We searched the Pan-STARRS 1 datastore to identify pre-outburst photometry of Nova Del 2013 and identified twenty-four observations in the 1.2 years before outburst. The progenitor of Nova Delphini showed variability of a few tenths of a magnitude but did not brighten significantly in comparison with archival plate photometry. We also found that the object did not vary significantly on the approximately half hour timescale between pairs of Pan-STARRS 1 observations.

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Blobrana


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Posts: 131433
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RE: Nova Del 2013
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NovaDel2013_081513westlake_key900.jpg

Using a small telescope to scan the skies on August 14, Japanese amateur astronomer Koichi Itagaki discovered a "new" star within the boundaries of the constellation Delphinus.



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Blobrana


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Posts: 131433
Date:
Nova Delphinus 2013
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A bright nova has recently been discovered in the constellation of Delphinus (The Dolphin). The discoverer was Koichi Itagaki, in Japan who used an 18 cm reflecting telescope with a CCD camera. 
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Blobrana


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Posts: 131433
Date:
Nova Del 2013
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Continuing spectroscopic observations (3500-8800A) of Nova Del 2013 with the Ondrejov Observatory and the ARAS group

Nova Del 2013



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