Search Publications
Detection of 7Be II in the Small Magellanic Cloud
Izzo, Luca; Selvelli, Pierluigi; Della Valle, Massimo +8 more
We analyse high-resolution spectra of two classical novae that exploded in the Small Magellanic Cloud (SMC). 7Be II resonance transitions are detected in both ASASSN-19qv and ASASSN-20ni novae. This is the first detection outside the Galaxy and confirms that thermo-nuclear runaway reactions, leading to the 7Be formation, are …
A study of the F-giant star θ Scorpii A: a post-merger rapid rotator?
Lewis, Fiona; Bailey, Jeremy; Cotton, Daniel V. +3 more
We report high-precision observations of the linear polarization of the F1III star θ Scorpii. The polarization has a wavelength dependence of the form expected for a rapid rotator, but with an amplitude several times larger than seen in otherwise similar main-sequence stars. This confirms the expectation that lower-gravity stars should have strong…
Seimei KOOLS-IFU mapping of the gas and dust distributions in Galactic planetary nebulae: the case of IC 2165
Otsuka, Masaaki
We investigated the physical and chemical properties of the gas and dust components in a carbon-rich planetary nebula (PN) IC 2165 using two-dimensional emission-line maps with superior resolution. The extinction map is generated in a self-consistent and assumption-free manner. The circumstellar gas-to-dust mass ratio (GDR) map ranges radially fro…
Planetary nebulae with Wolf-Rayet-type central stars - IV. NGC 1501 and its mixing layer
Guerrero, M. A.; Toalá, J. A.; Todt, H. +4 more
Theory predicts that the temperature of the X-ray-emitting gas (~106 K) detected from planetary nebulae (PNe) is a consequence of mixing or thermal conduction when in contact with the ionized outer rim (~104 K). Gas at intermediate temperatures (~105 K) can be used to study the physics of the production of X-ray-em…
Physical conditions and chemical abundances of the variable planetary nebula IC 4997
Parthasarathy, M.; Danehkar, A.
The planetary nebula (PN) IC 4997 is one of a few rapidly evolving objects with variable brightness and nebular emission around a hydrogen-deficient star. In this study, we have determined the physical conditions and chemical abundances of this object using the collisionally excited lines (CELs) and optical recombination lines (ORLs) measured from…