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PS(陈培生), Chen; XH, Wang; He, J.-J.

doi:10.1023/a:1002405302952

Cited by 14 publications

(8 citation statements)

References 15 publications

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“…The energy distribution of HD 190073 in this spectral region is similar to that of well known Herbig Ae stars, like AB Aur, HD 163296 and HD 31648 (Malfait et al 1998). According to Chen et al (2000), the size and the structure of the 9.7 µm silicate feature in the spectrum of the object resembles those observed in AB Aur and HD 163296.…”

Section: Introductionmentioning

confidence: 65%

Spectroscopic behaviour of the unusual Ae star HD 190073

Погодин

Franco²,

Lopes

2005

A&A

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Abstract.The results of high-resolution spectroscopy of the peculiar Ae star HD 190073 obtained within the framework of a cooperative observing programme in 1994-2002 are presented. The temporal behaviour of the Hα, Hβ, Hγ, Hδ, He  λ 5876 Å, Na  D and other circumstellar line profiles are investigated in detail. Special attention has been paid to the analysis of the deep multicomponent blueshifted Ca  H and K absorption lines. It has been found that the fine structure of their profiles is variable on timescales from months to decades. The analysis of the circumstellar spectrum of HD 190073, rich in shell-like and emission lines with narrow absorption cores, allows us to conclude that all absorption lines and cores are likely to be of photospheric origin. The emission lines are variable in time and demonstrate signs of a stellar wind as well as a dense equatorial circumstellar disk. As a preliminary hypothesis, we propose that a global magnetic field of a specific topology can be responsible for the formation of stable latitudinal stratification of the outflowing gas resulting in appearance of the complex structure of the Ca  H and K line profiles. We emphasise that a measurement of the stellar magnetic field and an investigation of its detailed configuration would be an important step in understanding the nature of HD 190073.

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Section: Introductionmentioning

confidence: 65%

Spectroscopic behaviour of the unusual Ae star HD 190073

Погодин

Franco²,

Lopes

2005

A&A

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“…But he also mentioned that the IR emission of the object may be variable. Later on Sitko et al (1999) and Chen et al (2000) analyzed the spectrum of HD 31648 in the interval 3-14 µm obtained with higher resolution (∆λ ∼ 0.2 µm) and concluded that in both size and structure the 9.7 µm silicate feature resembles those observed in the pre-main sequence (PMS) Herbig Ae/Be stars and in solar system comets.…”

Section: Background Informationmentioning

confidence: 99%

Active phenomena in the circumstellar environment of the Herbig Ae star HD 31648

Beskrovnaya

Погодин

2004

A&A

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Abstract. We present the results of observations of the Herbig Ae star HD 31648 including high-resolution spectroscopy near the Hα, He  λ 5876 Å and DNa  lines, multi-color photometry and polarimetry. These observations have revealed many features of the observational appearance of HD 31648 similar to those of the "classical" Herbig Ae stars. Among them are spectral manifestations of both the mass loss and the disk accretion onto the star and certain types of line profile variations. The totality of the observed properties of HD 31648 provides evidence in favor of complicated structure in the stellar wind zone, exhibiting latitudinal stratification and containing local inhomogeneities in the form of outflowing streams and density condensations. Structural variations of the stellar wind have been found to correlate with changes in the accretion process in the envelope. The circumstellar environment of HD 31648 is supposed to contain dust particles of different forms manifesting themselves, in particular, in the variable multi-component intrinsic polarization.

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“…They are usually found in those stars with spectral types A, B and F, in most instances spatially correlated with dark clouds or bright nebulosities (Herbig, 1960;Thé et al, 1994;Waters and Waelkens, 1998). A feature common to all HAEBE stars is the presence of infrared excess due to thermal radiation of circumstellar dust (Strom et al, 1972;Cohen, 1973;Cohen and Kuhi, 1979;Chen et al, 2000). Finkenzeller and Mundt (1984) studied 57 HAEBE stars and concluded that: the IR excesses of HAEBE stars are much stronger than those of ordinary Be stars, and the two groups are well separated in the H-K, K-L two-color diagram.…”

Section: Introductionmentioning

confidence: 99%

An infrared study of Herbig Ae/Be stars

Zhang

Yang

Liu

2006

Astrophys Space Sci

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The IRAS and 2MASS associations for 206 HAEBE stars are identified in this paper. From the colorcolor diagrams and spectral index, it is found that the IR excesses for most samples are due to thermal emission from the circumstellar material. It is also found that the IR excesses at IRAS region for few HAEBE stars and the near-IR excesses for some HAEBE stars are likely attributed to freefree emission or free-bound emission from the circumstellar ionized gas. Moreover, the evolution scenario (from embedded HAEBE stars to β Pictoris-like main-sequence stars) from Malfait et al. (1998) has been checked, our result does not support this evolution scenario.

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Cited by 14 publications

References 15 publications

Spectroscopic behaviour of the unusual Ae star HD 190073

Spectroscopic behaviour of the unusual Ae star HD 190073

Active phenomena in the circumstellar environment of the Herbig Ae star HD 31648

An infrared study of Herbig Ae/Be stars

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