Detailed studies of IPHAS sources — I. The disrupted late bipolar IPHASX J193718.6+202102
Sabin, L.;Guerrero, M. A.;Zavala, S.;Toalá, J. A.;Ramos-Larios, G.;Gómez-Llanos, V.
Abstract: We present a detailed analysis of the new planetary nebula (PN) IPHASX J193718.6+202102 using deep imaging and intermediate- and high resolution spectroscopy that are interpreted through morpho-kinematic and photoionisation modelling. The physical structure of the nebula consists of a fragmented torus and an extremely faint orthogonal bipolar outflow, contrary to the pinched waist PN morphology suggested by its optical image. Our kinematic analysis indicates that the torus is expanding at 25±5 km s−1 and is gradually breaking up. At an estimated distance of 7.1−0.3+0.8 kpc, the corresponding kinematic age of ∼26000 years is consistent with a faint and disintegrating PN. The intermediate-resolution spectra reveal an excited PN with chemical abundances typical of Type II PNe. Based on the latter we also estimate an initial mass for the progenitor in the range 2-3 M⊙ and a central star (CSPN) mass MCSPN∼0.61 M⊙. The Spitzer MIPS 24 μμm emission that closely follows the fragmented torus could be attributed to the emission of [O IV] at 25.9 μμm rather than to dust emission. All the results coherently point towards an evolved moderately massive bipolar Type II PN on the brink of dissolving into the interstellar medium.
Journal: Monthly Notices of the Royal Astronomical Society (MNRAS), in press Preprint
A triple-star system with a misaligned and warped circumstellar disk shaped by disk tearing
Stefan Kraus, Alexander Kreplin, Alison K. Young, Matthew R. Bate, John D. Monnier, Tim J. Harries, Henning Avenhaus, Jacques Kluska, Anna S. E. Laws, Evan A. Rich, Matthew Willson, Alicia N. Aarnio, Fred C. Adams, Sean M. Andrews, Narsireddy Anugu, Jaehan Bae, Theo ten Brummelaar, Nuria Calvet, Michel Curé, Claire L. Davies, Jacob Ennis, Catherine Espaillat, Tyler Gardner, Lee Hartmann, Sasha Hinkley, Aaron Labdon, Cyprien Lanthermann, Jean-Baptiste LeBouquin, Gail H. Schaefer, Benjamin R. Setterholm, David Wilner, Zhaohuan Zhu
Abstract: Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems can disrupt the disk. Theoretical models predict that if the disk is misaligned with the orbital plane of the stars, the disk should warp and break into precessing rings, a phenomenon known as disk tearing. We present observations of the triple-star system GW Orionis, finding evidence for disk tearing. Our images show an eccentric ring that is misaligned with the orbital planes and the outer disk. The ring casts shadows on a strongly warped intermediate region of the disk. If planets can form within the warped disk, disk tearing could provide a mechanism for forming wide-separation planets on oblique orbits.
