A THREE-DIMENSIONAL VIEW OF THE REMNANT OF NOVA PERSEI 1901 (GK Per)

• Published in: The Astrophysical journal 2012-12, Vol.761 (1), p.1-13
• Main Authors: LIIMETS, T, Corradi, R L M, Santander-Garcia, M, VILLAVER, E, Rodriguez-Gil, P, Verro, K, Kolka, I
• Format: Article
• Language: English
• Subjects: ACCELERATION; ANISOTROPY; ASTRONOMY; ASTROPHYSICS; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; DISTANCE; DOPPLER EFFECT; Ejecta; Fading; Homogenizing; JETS; Knots; NEBULAE; NITROGEN IONS; Nova; NOVAE; Outflow; PROPER MOTION; RADIAL VELOCITY; STAR EVOLUTION; STELLAR WINDS; Three dimensional; THREE-DIMENSIONAL CALCULATIONS
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/761/1/34

We present a kinematical study of the optical ejecta of GK Per. It is based on proper-motion measurements of 282 knots from ~20 images spanning 25 years. Doppler shifts are also computed for 217 knots. The combination of proper motions and radial velocities allows a unique three-dimensional view of the ejecta to be obtained. The main results are as follows: (1) the outflow is a thick shell in which knots expand with a significant range of velocities, mostly between 600 and 1000 km s super(-1), (2) kinematical ages indicate that knots have suffered only a modest deceleration since their ejection a century ago, (3) no evidence for anisotropy in the expansion rate is found, (4) velocity vectors are generally aligned along the radial direction, but a symmetric pattern of non-radial velocities is also observed at specific directions, and (5) the total H[alpha]+[NII] flux has been linearly decreasing at a rate of 2.6% per year in the past decade. The eastern nebular side is fading at a slower rate than the western side. Some of the knots were displayed a rapid change of brightness during the 2004-2011 period. Over a longer timescale, a progressive circularization and homogenization of the nebula are taking place; (6) a kinematic distance of 400 + or - 30 pc is determined. These results raise some problems with the previous interpretations of the evolution of GK Per. In particular, the idea of a strong interaction of the outflow with the surrounding medium in the southwest quadrant is not supported by our data.