IPHAS and the symbiotic stars

Abstract

Context. Knowledge of the total population of symbiotic stars in the Galaxy is important for understanding basic aspects of stellar evolution in interacting binaries and the relevance of this class of objects in the formation of supernovae of type Ia. Aims. In a previous paper, we presented the selection criteria needed to search for symbiotic stars in IPHAS, the INT Hα survey of the Northern Galactic plane. IPHAS gives us the opportunity to make a systematic, complete search for symbiotic stars in a magnitude-limited volume. Methods. Follow-up spectroscopy at different telescopes worldwide of a sample of sixty two symbiotic star candidates is presented. Results. Seven out of nineteen S-type candidates observed spectroscopically are confirmed to be genuine symbiotic stars. The spectral type of their red giant components, as well as reddening and distance, were computed by modelling the spectra. Only one new D-type symbiotic system, out of forty-three candidates observed, was found. This was as expected (see discussion in our paper on the selection criteria). The object shows evidence for a high density outflow expanding at a speed ≥65 km s −1 . Most of the other candidates are lightly reddened classical T Tauri stars and more highly reddened young stellar objects that may be either more massive young stars of HAeBe type or classical Be stars. In addition, a few notable objects have been found, such as three new Wolf-Rayet stars and two relatively high-luminosity evolved massive stars. We also found a helium-rich source, possibly a dense ejecta hiding a WR star, which is surrounded by a large ionized nebula. Conclusions. These spectroscopic data allow us to refine the selection criteria for symbiotic stars in the IPHAS survey and, more generally, to better understand the behaviour of different Hα emitters in the IPHAS and 2MASS colour-colour diagrams.

Spatial distribution of Galactic Wolf–Rayet stars and implications for the global population

“…( (23) Chené et al (2013), (24) Rahman, Moon, & Matzner (2011), (25) Anderson et al (2011), (26) Marston et al (2013), (27) Kanarek et al (2014), (28) Davies et al (2012), (29) de La Fuente, Najarro, Davies, & Figer (2013), (30) Borissova et al (2012), (31) Mikles et al (2006), (32) Hyodo et al (2008), (33) Faherty et al (2014) (34) Smith et al (2012), (35) Corradi et al (2010), (36) Gvaramadze et al (2009), (37) Burgemeister et al (2013) He ii This paper has been typeset from a T E X/ L A T E X file prepared by the author.…”

A wealth of new planetary nebulae from the IPHAS survey

“…Its 98-min period makes it the PNe with the binary central star with the shortest orbital period, and a type Ia SN progenitor candidate (Rodríguez-Gil et al 2010). Among PN related sources, the discovery of a number of S-type stars among the the reddest IPHAS stars (Wright et al 2008), and the discovery of new symbiotic stars (Corradi et al , 2010, should also be mentioned.…”

The ongoing outburst of the new symbiotic star IPHASJ190832.31+051226.6

“…Also, from the equivalent widths of the CO band at 2.29 μm, the Na I doublet at 2.208 μm, and the Ca I triplet at 2.265 μm, we estimate a solar-like metallicity Combining all the different indicators, the red giant of IPHAS J190832.31+051226.6 is constrained to between early M4 III and late M5 IIII. With the calibration into absolute magnitudes of M giants as discussed in Corradi et al (2010), a distance for IPHAS J190832.31+051226.6 between 3.3 and 5.4 kpc is obtained. The range of possible distances and reddening values is plotted in Fig.…”

“…The range of possible distances and reddening values is plotted in Fig. 4 and is compared with the extinctiondistance relationship along the line of sight to the source provided by IPHAS (see Sale et al 2008;and Corradi et al 2010). In the figure, empty circles indicate the curve derived using hundreds of field stars in a 10 × 10 box around the line of sight toward IPHAS J190832.31+051226.6.…”

“…Among them, Corradi et al (2008Corradi et al ( , 2010 present the discovery of eleven symbiotic stars, doubling the number of objects of this class known in this area of the sky. Corradi et al (2010) indicate two additional candidates: one of them -named IPHAS J190832.31+051226.6 according to its J2000 coordinates -was noticed to have brightened significantly from 2004 to 2008. This raised our interest in the source, so we obtained new photometric and spectroscopic data that are presented here.…”