99 citations · 289 across the 14 of their papers we have counts for
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Is the nitrogen-rich source PN K4-47 a true planetary nebula?
Thomas Steinmetz, Tomasz Kaminski, David Jones +3
PN K4-47 is a young planetary nebula that exhibits shock-excited bipolar lobes and a complex molecular environment, with the highest number of molecules detected within a planetary…
Planetary Nebulae
Orsola De Marco, Isabel Aleman, Stavros Akras
Planetary nebulae are formed by the matter ejected by low-to-intermediate mass stars (~0.8-8 times the mass of the Sun) towards the end of their lives. As hydrogen and then helium…
[Fe II] 1.644m imaging survey of planetary nebulae with low-ionisation structures
Stavros Akras, Isabel Aleman, Denise R. Gonçalves +2
Low-ionisation structures (LISs) are commonly found in planetary nebulae (PNe) but they are still poorly understood. The recent discovery of unforeseen molecular hydrogen gas (H2)…
RAMSES II - RAMan Search for Extragalactic Symbiotic Stars. Project concept, commissioning, and early results from the science verification phase
R. Angeloni, D. R. Gonçalves, S. Akras +16
Symbiotic stars (SySts) are long-period interacting binaries composed of a hot compact star, an evolved giant star, and a tangled network of gas and dust nebulae. They represent un…
A census of symbiotic stars in the 2MASS, WISE and Gaia surveys
Stavros Akras, Lizette Guzman-Ramirez, Marcelo L. Leal-Ferreira +1
We present a new census of Galactic and extragalactic symbiotic stars (SySts). This compilation contains 323 known and 87 candidate SySts. Of the confirmed SySts, 257 are Galactic…
A machine learning approach for identification and classification of symbiotic stars using 2MASS and WISE
Stavros Akras, Marcelo L. Leal-Ferreira, Lizette Guzman-Ramirez +1
In this second paper in a series of papers based on the most-up-to-date catalogue of symbiotic stars (SySts), we present a new approach for identifying and distinguishing SySts fro…
Reclassifying symbiotic stars with 2MASS and WISE: An atlas of spectral energy distribution
Stavros Akras, Lizette Guzman-Ramirez, Marcelo Leal-Ferreira +1
We present a new updated catalogue of Galactic and extragalactic symbiotic stars (SySts). Since the last catalogue of SySts (Belczynski et al. 2000), the number of known SySts has…
H in low-ionization structures of planetary nebulae
Stavros Akras, Denise R. Gonçalves, Gerardo Ramos-Larios
We report the detection of near-IR H emission from the low-ionization structures (knots) in two planetary nebulae. The deepest ever, high-angular resolution H 1-0 S(1) at 2…
Proof of shock-excited H in low-ionization structures of PNe
Stavros Akras, Denise R. Gonçalves, Gerardo Ramos-Larios
We report the detection of near-IR H lines emission from low-ionization structures (LISs) in planetary nebulae. The deepest, high-angular resolution H 1-0 S(1) at 2.122 …
Discovery of true, likely and possible symbiotic stars in the dwarf spheroidal NGC 205
Denise R. Gonçalves, Laura Magrini, Ignacio G. de la Rosa +1
In this paper we discuss the photometric and spectroscopic observations of newly discovered (symbiotic) systems in the dwarf spheroidal galaxy NGC 205. The Gemini Multi-Object Spec…