摘要
We present evidences showing that the Be star 3G71, proposed as the optical cou- nterpart of the Be / X-ray binary source 1H2214 + 589, may be a Herbig Ae / Be star. These evidences can be summarized as follows. 1. We made spectroscopic observations by using a CCD spectrograph with dispersi- ons 50 A / mm and 195 A / mm at the BAO 2.16m telescope. Analysis of the optical spectra of 3G71 indicates: a. Forbidden lines, such as [OI] 6300 and 6363 A, [FeII] 5527, 4889, 4814, 4415, 4359 and 4304 A, are present in the spectra (Fig.2a, Fig.2b). b. The Hα emission line is unusually strong. Its equivalent width is sometimes more than 100 A (Fig. 1). The photospheric absorption lines of hydrogen are very wide. In the case of Hβ, the distance between two wings amounts to 60 A (Fig.2a, Fig.3). 2. We have performed cross-identification between HST GSC catalogue and IRAS Point Source Catalogue and found the IRAS point souree counterpart of 3G71 to be 2248 + 6058. Its equatorial coordinates (at equinox 1950.0) are 22h24m53s.8 and +60°58′ 15″, while those given by the GSC catalogue are 22h24m53s.37 and +60°58′13″.1. The differences are merely 0.4s and 2″, being less than the uncertainty ellipse (major axis: 11″, minor axis: 6″) given in IRAS PSC. Table 1 lists the flux densities quoted from IRAS GSC and the deduced IRAS IR magnitudes. It is clear from the table that 3G71 has a very large IR color excess, since the V magnitude of 3G71 found from GSC is 12.2 and its V-[25]=+12.47, which is much larger than that expected for classical Be stars and satisfies the criterion for the Herbig Ae / Be stars given by Hu et al., i.e., V-[25] > 7. 3. Using Palomar sky survey map, we have made a search for a nebulosity in the immediate vicinity of 3G71 and actually discovered a bright nebula, at whose center 3G71 is just located. Its diameter is about 1 are-minute. It is concluded from the characteristics of 3G71 mentioned above that 3G71 may be a Herbig Ae / Be star.
We present evidences showing that the Be star 3G71, proposed as the optical cou- nterpart of the Be / X-ray binary source 1H2214 + 589, may be a Herbig Ae / Be star. These evidences can be summarized as follows. 1. We made spectroscopic observations by using a CCD spectrograph with dispersi- ons 50 A / mm and 195 A / mm at the BAO 2.16m telescope. Analysis of the optical spectra of 3G71 indicates: a. Forbidden lines, such as [OI] 6300 and 6363 A, [FeII] 5527, 4889, 4814, 4415, 4359 and 4304 A, are present in the spectra (Fig.2a, Fig.2b). b. The Hα emission line is unusually strong. Its equivalent width is sometimes more than 100 A (Fig. 1). The photospheric absorption lines of hydrogen are very wide. In the case of Hβ, the distance between two wings amounts to 60 A (Fig.2a, Fig.3). 2. We have performed cross-identification between HST GSC catalogue and IRAS Point Source Catalogue and found the IRAS point souree counterpart of 3G71 to be 2248 + 6058. Its equatorial coordinates (at equinox 1950.0) are 22h24m53s.8 and +60°58′ 15″, while those given by the GSC catalogue are 22h24m53s.37 and +60°58′13″.1. The differences are merely 0.4s and 2″, being less than the uncertainty ellipse (major axis: 11″, minor axis: 6″) given in IRAS PSC. Table 1 lists the flux densities quoted from IRAS GSC and the deduced IRAS IR magnitudes. It is clear from the table that 3G71 has a very large IR color excess, since the V magnitude of 3G71 found from GSC is 12.2 and its V-[25]=+12.47, which is much larger than that expected for classical Be stars and satisfies the criterion for the Herbig Ae / Be stars given by Hu et al., i.e., V-[25] > 7. 3. Using Palomar sky survey map, we have made a search for a nebulosity in the immediate vicinity of 3G71 and actually discovered a bright nebula, at whose center 3G71 is just located. Its diameter is about 1 are-minute. It is concluded from the characteristics of 3G71 mentioned above that 3G71 may be a Herbig Ae / Be star.
出处
《天文学报》
CSCD
北大核心
1997年第3期324-330,共7页
Acta Astronomica Sinica
基金
国家自然科学基金
中国科学院天文委员会的资助
