TOWARD UNDERSTANDING THE B[e] PHENOMENON. III. PROPERTIES OF THE OPTICAL COUNTERPART OF IRAS 00470+6429

Abstract

1 Partially based on data obtained at the 6-m BTA telescope of the Russian Academy of Sciences, 3-m IRTF, 3-m Shane telescope of the Lick Observatory, 2.7-m Harlan J. Smith and 2.1-m Otto Struve telescopes of the McDonald Observatory, 2.1-m telescope of the San Pedro Martir Observatory, 1.5-m telescope of the Loiano Observatory, and 0.8-m telescope of the Dark Sky Observatory ABSTRACT FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in [2003][2004][2005][2006][2007][2008]. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li I 6708Å line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral type primary companion of a luminosity log L/L⊙ = 3.9±0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0±0.3 kpc from the Sun.

Peculiarities of the atmosphere and envelope of a post-AGB star, the optical counterpart of IRAS 23304+6347

“…The presence of an analogous interstellar component with Vr≈ −63 km/s in the spectra of the B-stars HD 4841, HD 4694, and Hiltner 62, whose positions in the Galaxy are close to the longitude of IRAS 23304, serves as an argument for this. The spectra of these stars, members of the Cas OB7 association, were studied by Miroshnichenko et al (2009). The presence of the component with Vr =−61.6 km/s allows us to consider the distance to the Cas OB7 association d = 2.5 kpc from Cazzolato and Pineault (2003) as a lower limit for the distance to IRAS 23304.…”

“…According to the results of Miroshnichenko et al (2009), there are diffuse interstellar bands (DIBs) with velocities in the range −11 ÷ −14 km/s in the spectra of the hot stars HD 4841, HD 4694, and Hiltner 62 mentioned above. It is also natural to expect the presence of DIBs in the spectra of the optical counterpart of IRAS 23304.…”

First detections of FS Canis Majoris stars in clusters

“…Subsequent observations (Miroshnichenko et al , 2009(Miroshnichenko et al , 2011aBorges Fernandes et al 2009Rodríguez et al 2012;Polster et al 2012;Liermann et al 2014) and modeling (Carciofi et al 2010;Borges Fernandes et al 2011) of FS CMa stars have not been capable of unraveling the enigmatic nature of these objects. One of the most puzzling issues refers to the observationally inferred mass-loss rates, which are 2-3 dex higher than predicted by wind theory for B-type main-sequence stars.…”

“…Although the FS CMa star IRAS 00470+6429 is projected towards the Cas OB7 association , membership is unlikely due to the absence of a interstellar component of a Na i line that is present in the majority of the Cas OB7 members (Miroshnichenko et al 2009).…”

AMBER/VLTI observations of the B[e] star MWC 300

“…The binarity of MWC 349A has not been directly confirmed, but was suggested by Hofmann et al (2002). Although the exact role of binarity in the B[e] phenomenon is still an open question, it is possible that the disks are the result of mass exchange episodes between the stellar components of the B[e] stars (Sheikina et al 2000;Miroshnichenko 2007;Miroshnichenko et al 2007Miroshnichenko et al , 2009Kraus et al 2010Kraus et al , 2012b. The slowing down of the radiative wind by the companion gravitational effect or wind shock may also be an explanation (Plets et al 1995).…”