The Atmospheric Variations of the Peculiar B[e] Star HD 45677 (FS CMa)

Israelian, G.; Friedjung, M.; Graham, John W.; Muratorio, G.; Rossi, C.; Winter, D. de

doi:10.1017/s0252921100043669

Cited by 12 publications

(31 citation statements)

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“…The latter was found to be the case for HD 45677, a Be star with warm dust (Israelian et al 1996). Thus we accept the spectral types following from the photometry in the case of Hen 3-140 and from the photometry and the Balmer line wings fitting for HD 85567.…”

Section: Hd 85567 and Hen 3-140supporting

confidence: 57%

Spectroscopy of B-type emission-line stars with compact dusty envelopes: HD 85567, Hen 3-140, and Hen 3-1398

Мирошниченко

Levato

Bjorkman

et al. 2001

A&A

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Abstract.We report the results of our spectroscopic observations (3600-5900Å, R 16 000 and 5750-8750Å, R 11 000) of three southern emission-line B-type stars associated with IRAS sources, HD 85567, Hen 3-140, and Hen 3-1398, whose nature and evolutionary state are not well-established yet. We also obtained new multicolour photometry of HD 85567 (UBV (RI)cJHKL) and Hen 3-140 (JHKLM). A large near-IR excess is found in Hen 3-140 for the first time. All three objects show double-peaked Fe ii lines in emission. The Balmer emission lines are double-peaked in HD 85567 and Hen 3-140, while the He i lines are found in absorption. Hen 3-1398 displays triple-peaked Balmer lines as well as single-peaked He i and He ii lines in emission. Fundamental parameters of the stars are estimated on the basis of both photometric and spectroscopic data. The whole set of their properties resemble that of a recently defined group of Be stars with warm dust (Sheikina et al. 2000). IntroductionA large number of emission-line B-type stars were detected by the IRAS satellite because of the presence of infrared (IR) excesses in their spectral energy distributions (SED). These excesses are due to radiation of circumstellar gas and dust. Studies of their shapes and strengths help to constrain properties of the circumstellar matter and, in many cases and in combination with spectroscopic studies, the evolutionary state of the star. For example, Be stars with free-free IR excesses are main sequence objects, those with much stronger IR excesses due to dust particles in a wide range of temperatures and moderate luminosities are pre-main-sequence ones, while high-luminosity Betype stars with dusty IR excesses are usually post-mainsequence LBV stars or B[e] supergiants. However, it is difficult to form conclusions on the nature and evolutionary state of objects with dusty IR excesses, even with extensive observational data in hand. This was demonstrated by Thé et al. (1994), who compiled a catalogue of 287 such objects, properties of only about 50% of which are thought to be well understood.One of the examples of poorly-understood groups of early-type stars with IR excesses is the B[e] stars selected by Allen & Swings (1976), many of which are still unclassified (Lamers et al. 1998 Sheikina et al. 2000). Only about 10 such objects are contained in the original list of Allen & Swings (1976). However, the IRAS survey revealed more poorly studied early-type stars with the mentioned IR properties; these stars are the focus of our investigation. Recently we completed an extensive study of 2 new members of this group, AS 78 and MWC 657 , and suggested that they might be binaries. Here we report the results of a study of three southern emission-line objects (HD 85567, Hen 3-140, and Hen 3-1398), whose properties turned out to be similar to those of the objects from Sheikina et al. (2000). For the sake of brevity, hereafter we will refer to entire group as Be stars with warm dust.The objects of this study, which are listed in the catalogue of Thé et al. (1...

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Section: Hd 85567 and Hen 3-140supporting

confidence: 57%

Spectroscopy of B-type emission-line stars with compact dusty envelopes: HD 85567, Hen 3-140, and Hen 3-1398

Мирошниченко

Levato

Bjorkman

et al. 2001

A&A

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“…3 underwent dramatic variation in both intensity and position of the emission components, as well as in the intensity of the central absorption (its position is stable within the fitting precision). This behaviour is not unexpected because Israelian et al (1996) report variability for these lines within 2−3 days. Due to the intense absorption, the narrow emission component, if present, cannot be found by the fitting procedure.…”

Section: Line Componentssupporting

confidence: 52%

“…The 1995 observations were used in 1996 for the analysis of the He I lines 4387, 4471, 5876 and 4438 Å (Israelian et al 1996).…”

Section: Observations and Reductionsmentioning

confidence: 99%

“…These last authors agreed on the presence, around the star, of an actively accreting circumstellar, protoplanetary disk, and the presence of low-velocity absorption profiles in Fe II lines, among other species, while optical spectroscopic measurements of strong absorption cores of a few lines are commented on by de Winter et al (1997). In the optical HD 45677 is characterised by a rich emission line spectrum, including the Balmer lines of hydrogen, and both permitted and forbidden lines of neutral and ionized metals (Mg I, Mg II, Na I, Cr II Israelian et al (1996) found a surface gravity of log g = 3.85 ± 0.05 (luminosity class V) from the photospheric wings of Hγ and Hδ, while examination of the He I absorption lines suggested a spectral class of B2 (T eff = 22 000 ± 1500 K). The effective temperature was less certain than the surface gravity, due to a circumstellar contribution to the He I lines.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the circumstellar environment of the B[ e] star HD 45677 (FS Canis Majoris)

Muratorio¹,

Rossi²,

Friedjung³

2006

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Aims. We studied the circumstellar environment of the B[e] star HD 45677 through the analysis of the emission lines from ionized metals. Methods. We used the statistical approach of the self absorption curve method (SAC) to derive physical parameters of the line emitting region. Results. The Fe II and Cr II double-peaked emission line structure is explained by the presence of a thin absorption component red shifted by ∼3 km s −1 . This absorption component can be interpreted geometricaly as being due to infalling material perpendicularly to the disk seen nearly pole-on, as indicated by the emission line structure. The Cr II and Fe II emission lines have a complex structure with two (narrow and broad) components, of 45 and 180 km s −1 FWHM for the permitted lines and 25 and 100 km s −1 FWHM for the forbidden ones, respectively. From our best data set of 1999, we obtained a Boltzmann-type population law whose excitation temperature is 3900 +900 −600 K and 3150 +350−300 K for the narrow component lower and upper levels respectively. We obtained an excitation temperature of 3400 +350 −300 K for the broad component upper levels. The forbidden lines are found to be formed in the outer regions with higher excitation temperatures of 10 500 ± 1000 K and 8000 ± 1500 K for the narrow and broad components respectively in 1999. Our results are consistent with line formation in a rotating disk, around a young star. In the framework of a very simplified geometrical model, we argue that the narrow components are principaly emitted by an optically thin disk seen nearly pole-on, in a region whose minimum radius is estimated to be 4×10 12 cm, while the broad ones are formed in a disk-linked wind.

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“…He detected split Fe  lines. The photospheric absorption line spectrum was analyzed by Israelian et al (1996) who derived T eff = 22 000 K and log g = 3.9, consistent with the spectral type of B2V. Spectroscopic variablitity was studied by Israelian & Musaev (1997 HD 87643 is embeddded in a reflection nebula (Henize 1962) for which Surdej et al (1981) found an expansion velocity of about 150 km s −1 .…”

Section: C11 Hd 45677 (=Fs Cma)mentioning

confidence: 96%

Kinematical structure of the circumstellar environments of galactic B[e]-type stars

Zickgraf

2003

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Abstract. High resolution line profiles are presented for selected forbidden and permitted emission lines of a sample of galactic B[e]-type stars. The spectral resolution corresponds to 5−7 km s −1 with the exception of some line profiles which were observed with a resolution of 9−13 km s −1 . All Hα profiles are characterized by a narrow split or single emission component with a width of ∼150−250 km s −1 (FWHM) and broad wings with a full width of ∼1000−2000 km s −1 . The Hα profiles can be classified into three groups: double-peaked profiles representing the majority, single-peaked emission-line profiles, and normal P Cygni-type profiles. Likewise, the forbidden lines exhibit in most cases double-peaked profiles. In particular, the majority of stars shows split [O ]λ6300 Å. Double-peaked profiles are also found in several stars for [N ]λ6583 Å and [Fe ]λ7155 Å although these lines in many stars exhibit single-peaked emission profiles. The split forbidden line profiles have peak separations of as little as ∼10 km s −1 , and were therefore only discernible for the first time in the high-resolution spectra. The ratio of violet to red emission peak intensities, V/R, is predominantly smaller or equal to 1. Theoretical profiles were calculated for the optically thin case. A latitude-dependent stellar wind with a radial expansion and a velocity decreasing from the pole to the equator was adopted. This configuration can produce split line profiles if viewed under some angle with respect to the line of sight. In addition an equatorial dust ring with various optical depths was assumed. It can explain line asymmetries observed in some stars. Moreover, the V/R ratios can be understood in terms of this model. The comparison of the observed line profiles with the models thus confirms the assumption of disk-like line-formation regions as commonly adopted for B[e]-type stars.

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The Atmospheric Variations of the Peculiar B[e] Star HD 45677 (FS CMa)

Cited by 12 publications

References 1 publication

Spectroscopy of B-type emission-line stars with compact dusty envelopes: HD 85567, Hen 3-140, and Hen 3-1398

Spectroscopy of B-type emission-line stars with compact dusty envelopes: HD 85567, Hen 3-140, and Hen 3-1398

Analysis of the circumstellar environment of the B[ e] star HD 45677 (FS Canis Majoris)

Kinematical structure of the circumstellar environments of galactic B[e]-type stars

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