Four-color and H-beta photometry of open clusters. XII - NGC 6910 and NGC 6913

Crawford, D. L.; Barnes, J. V.; Hill, George A.

doi:10.1086/112093

Cited by 21 publications

(25 citation statements)

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“…In the nucleus area extinction is variable, Ay being between 3.2 and 3.9 mag. The mean extinction value Ay = 3.65 mag is in good agreement with the results by Crawford (1977). Judging from its distance and Ay value, the supergiant Tifft 2 (HD 194279) is a probable member of NGC 6910.…”

Section: Discussionsupporting

confidence: 88%

“…They were used to derive the mean distance of the cluster which is r = 1530±120 pc. This value is in good agreement with the results from Crawford et al (1977), Schmidt (1963) and Reddish (1967) obtained from the uvby and UBV photometries and spectral classification, but disagrees with the value r = 980 pc obtained by Shevchenko (1989). The plot "extinction versus distance" is shown in Fig.…”

Section: Discussionsupporting

confidence: 82%

“…2) and to find the age of the cluster. Coropa-- rison with the Maeder and Meynet (1989) evolutionary tracks shows that the age of NGC 6910 is less than 7 • 10® years, which confirms Shevchenko (1989) and Davies and Tovmassian (1963) conclusions that this open cluster is extremely young and is geneologically related with the emission nebulae surrounding it almost symmetrically.…”

Section: Discussionsupporting

confidence: 69%

“…n 3 ) £(1950)= +40°37' near 7 Cyg is situated in the area where interstellar extinction is large and very uneven: within cluster boundaries EB-V varies between 0.9 and 1.3 (Crawford et al, 1977). Due to this the distance of star forming complex RSF 2 Cyg (Shevchenko, 1989) and its age are rather problematic.…”

Section: Introductionmentioning

confidence: 99%

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Photoelectric Vilnius Photometry in the Direction of the Open Cluster NGC 6910

Vansevičius¹

1992

Open Astronomy

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Abstract. Photoelectric Vilnius photometry of 17 stars in the direction of the nucleus of the open cluster NGC 6910 is presented. Spectral types, absolute magnitudes, interstellar extinctions and distances of the stars are determined. The distance of the cluster based on ten O and B stars from the list is evaluated to be 1530 pc, its mean extinction is Ay -3.65 mag and the age is less than 7-10 6 years.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 82%

Section: Discussionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

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Photoelectric Vilnius Photometry in the Direction of the Open Cluster NGC 6910

Vansevičius¹

1992

Open Astronomy

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“…Since the original h and s Persei observations (Crawford, Glaspey, & Perry 1970) do not include V values, we used the values given by Johnson & Morgan (1955), which were also taken with the same instrumentation, for the V transformation. The list of standard stars used can be found in Table 2, along with their standard values used for the transformation, taken from and Johnson & Morgan (1955) for h and s Persei, Perry, Lee, & Barnes (1978) for NGC 2169, Crawford, Barnes, & Hill (1977) for NGC 6910, and Canterna, Perry, & Crawford (1979) for NGC 1039. Spectral types, when available, have been taken from Schild (1965) and Slettebak (1968) for h and s Persei, Perry et al (1978) for NGC 2169, Morgan & Harris (1956) and Applequist (1965) for NGC 6910, andCanterna et al (1979) for NGC 1039.…”

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confidence: 99%

Photometric and Spectroscopic Study of the Young Open Cluster NGC 1893

Marco

Bernabeu

Negueruela

2001

The Astronomical Journal

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We present uvbyb CCD photometry of the Ðeld of the open cluster NGC 1893. Our photometry is deep enough to cover the complete main-sequence B spectral type. We identify D50 very likely members of the cluster down to spectral type B9ÈA0, some of which have much higher reddenings than the average. We derive a color excess E(b[y) \ 0.33^0.03 and a dereddened distance modulus V 0 [M V \ 13.9^0.2. From the b index, we identify several candidates as emission-line stars, for which we have obtained spectroscopy. Three of them display spectra corresponding to spectral type F but showing Ha in emission. Photometric measurements in this and previous studies indicate strong variability. These characteristics show them to be preÈmain-sequence stars of spectral type F. We also identify two likely Herbig Be stars. These results hint at the existence of a sizable preÈmain-sequence population in NGC 1893.

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A search for luminous Be stars

Negueruela

2004

Astron Nachr

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Abstract. As Be stars are restricted to luminosity classes III-V, but early B-type stars are believed to evolve into supergiants, it is to be expected that the Be phenomenon disappears at some point in the evolution of a moderately massive star, before it reaches the supergiant phase. As a first stage in an attempt to determine the physical reasons of this cessation, a search of the literature has provided a number of candidates to be Be stars with luminosity classes Ib or II. Spectroscopy has been obtained for candidates in a number of open clusters and associations, as well as several other bright stars in those clusters. Among the objects observed, HD 207329 is the best candidate to be a high-luminosity Be star, as it appears like a fast-rotating supergiant with double-peaked emission lines. The lines of HD 229059, in Berkeley 87, also appear morphologically similar to those of Be stars, but there are reasons to suspect that this object is an interacting binary. At slightly lower luminosities, LS I +56• 92 (B4 II) and HD 333452 (O9 II), also appear as intrinsically luminous Be stars. Two Be stars in NGC 6913, HD 229221 and HD 229239, appear to have rather higher intrinsic magnitudes than their spectral type (B0.2 III in both cases) would indicate, being as luminous as luminosity class II objects in the same cluster. HD 344863, in NGC 6823, is also a rather early Be star of moderately high luminosity. The search shows that, though high-luminosity Be stars do exist, they are scarce and, perhaps surprisingly, tend to have early spectral types.

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Four-color and H-beta photometry of open clusters. XII - NGC 6910 and NGC 6913

Cited by 21 publications

References 0 publications

Photoelectric Vilnius Photometry in the Direction of the Open Cluster NGC 6910

Photoelectric Vilnius Photometry in the Direction of the Open Cluster NGC 6910

Photometric and Spectroscopic Study of the Young Open Cluster NGC 1893

A search for luminous Be stars

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