Star In Cygnus Research Articles

Polarization of a Heavily Obscured Clustering of OB Stars in Cygnus.

Polarization of a Heavily Obscured Clustering of OB Stars in Cygnus.

A Study of the Concentration of Early-Type Stars in Cygnus.

A Study of the Concentration of Early-Type Stars in Cygnus.

A spectroscopic study of Wolf-Rayet stars.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A spectroscopic study of Wolf-Rayet stars. Bappu, M. K. Vainu Abstract A study has been made of the profiles and total intensities of the emission lines of seven bright Wolf-Rayet stars in Cygnus, three of which belong to the carbon sequence and the rest to the nitrogen sequence. The well known eclipsing binary CQ Cephei was also included on the program, and the variations in the profiles of the emission lines and their total intensities during a cycle investigated. The broad emission band X4058, tentatively identified as due to Niv, has been found to be split into three components with wave lengths of 4044, 4057, and 4066 A. The lines X4044 and X4066 have been tentatively identified as due to Nii and Ciii, respectively. The line X4066 Ciii is moderately strong in carbon stars and as carbon lines have been found in nitrogen stars this identification is probably correct. The flat-topped nature of X4058, as shown by Beals to exist in BD 3504001, can then be explained as due to the *Of papers presented at the Eighty-fifth Meeting of the American Astronomical Society, Washington, D. C., J'ine 20-23, 1951. blending by physical causes of these components. The line ~5696 in carbon stars, identified as due to Ciii, has been observed to have a short wavelength component, X568 I, which has been tentatively identified with the 3s1P0-3P1D transition of Nii. If such an identification is correct, one would expect the transition 3S3PO~3p3P, X4630, to be observable and of medium intensity. The observation of this line is difficult because of the violet-absorption edge of X4650 due to Ciii. Nevertheless, the line has `been detected in BD 3504013. The occurrence of central reversals in WolfRayet stars is a rare phenomenon. The spectrograms of BD 3504001 reveal a deep core for ~4686 Heii, and a faint one for X54I I Heii. These might be central reversals or they may possibly be due to a non-uniform distribution of the emission on the stellar surface. Intrinsic variations of the spectral lines, as has been shown by Struve' to exist in HD 151932, have been found in two stars of the nitrogen sequence, BD 3703821 and BD 3504(>()I. The emission line X4603 Nv and its violet-edge experience changes in intensity. The line X4640 of Niii, and the Niii lines blended with N4542 Heii as well as ~447I Hei also show marked fluctuations. In the case of the eclipsing variable CQ Cephei, the profile of ~4686 Heii has been determined at different phases. While changes in form and intensity are immediately apparent, no marked asymmetry, as has been found by Beals2 for lIOL in V444 Cygni, has been found here. The intensities of the band X4640 have a curve of variation with phase, similar to the N4686 light curve derived recently by Hiltner.1 The line N4058 Niv has marked violet absorption edges at both primary and secondary minima. The changes in intensity of X4542 and X447 I are similar to those found by Mu~nch4 in V444 Cygni. I.Ap. J. 100, 198, 1944. 2.M. N. 104, 205, 1944. 3.Ap. J. 112, 477, 1950. 4.Ap. J. 112, 266, 1950. Harvard College Observatory, Cambridge, Mass. Publication: The Astronomical Journal Pub Date: 1951 DOI: 10.1086/106613 Bibcode: 1951AJ.....56R.120B full text sources ADS |

A Study of M-Type Stars in Cygnus.

view Abstract Citations (45) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Study of M-Type Stars in Cygnus. Nassau, J. J. ; van Albada, G. B. Abstract The present investigation is based on objective-prism spectra taken with the 2° and 4° prisms attach- d to the 24-inch Schmidt-type telescope, with I-N emulsion and Wratten No. 89 filter. The classification of the M stars was established solely on the TiO bands, while the carbon stars were lentified from the bands of CN. A new band near X 7950 is utilized in the identification of S stars. A and in the same spectral region has been observed in several late M stars-notably variables. The miting magnitude for which we believe our data to be complete is 13.5 infrared, although a number of tars are classified down to 14.5. The search for M stars was carried out in a relatively clear region in Cygnus at galactic longitude 41 ?2 nd latitude 3~7. The area is in the form of a rectangle perpendicular to the celestial equator and covers .28 square degrees. In this area 709 M stars were identified, 4 carbon stars, ~and 2 S stars; of the total ye found several new variables. The number of M stars per square degree is 311, while at galactic latitude f 9~2 and approximately at the same longitude the corresponding number is 31. Infrared magnitudes were established by assuming that the infrared intrinsic color for an A5 star is qual to zero. The median apparent infrared magnitude of the MO stars at ga]actic latitude 3~7 is 13.1, ~hich value decreases with advancing spectral type to 11.3 at M4. This isin agreement with the absolute rifrared magnitudes derived from the Mount Wilson spectroscopic absolute magnitudes, which give - 1.2 or MO and -3.0 for M4. For the late M types this relation does not seem to exist, since the observed nedian magnitudes remain stationary after M4. From our material it was possible to obtain the spectrum-intrinsic color relation for all the M stars; hey are given in Table 2. An estimate of the interstellar absorption of the region was found to give ).1O mag. per kiloparsec (infrared). The unevenness in the surface distribution of M stars indicates local egions of much heavier obscuration. A density analysis has been made from 627 stars (M0-M4). At a distance of 2 kpc from the sun the iumber of stars is 16X 10-6 per cubic parsec and at a distance of 6 kpc, 8X 1O~. For 107 stars from M2.5 to V14 the corresponding values are 4X 10-6 and O.7x 10-6, respectively. In comparison, at a distance of 8 ~pc the density was found to be 0.1 X 10-6 or less Publication: The Astrophysical Journal Pub Date: May 1949 DOI: 10.1086/145144 Bibcode: 1949ApJ...109..391N full text sources ADS | data products SIMBAD (2) Related Materials (2) Erratum: 1949ApJ...110..104. Erratum: 1949ApJ...110..104N

A study of M-type stars in Cygnus.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A study of M-type stars in Cygnus. Nassau, J. J. ; van Albada, G. B. Abstract This investigation is a continuation of our work in the infra-red spectra and magnitudes for M giants in the clear region of Cygnus. The primary additions to the observational data were derived by securing 20 objective prism spectral plates for our survey. The limiting magnitudes for which we believe our data to be complete is 13.5 infra-red, although a number of stars were classified down to 14.5. The classification of the M stars was based solely on the TiO bands, while the carbon stars were identified from the bands of CN. A new band near X 7950 has been utilized in the identification of S stars. A band in the same spectral region has been observed in several late M `s, notably variables. The search for M stars has been carried out in a relatively clear region in Cygnus at galactic longitude 430 and latitude 4?o. The area which is in the form of a rectangle, perpendicular to the celestial equator covers 2.28 square degrees. In this area 709 M stars were identified, four carbon stars and two S stars, among them several new variables. The number of M stars per square degree is 311, while at the galactic latitude of 9?2 and approximately the same longitude the corresponding number was 31. Even within the field itself a concentration toward the galactic plane is apparent. The median apparent infra-red magnitude of the Mo stars at galactic latitude 40 is 13.1 which value decreases with advancing spectral type to 11.3 at M4. This is in agreement with the absolute infra-red magnitudes, derived from the Mt. Wilson spectroscopic absolute magnitudes, which give -1.1 for Mo and -2.9 for M4. For the later M types this relation does not seem to exist since the observed median magnitudes remain stationary after M4. From our material it was possible to obtain the spectrum intrinsic color relation for all the M's, as follows: at Mo 1.1. (photographic minus infra-red magnitude) equal to 2.8, at M~ I.I. equal to 4.3. The amount of interstellar absorption of the region was found to be equal to 0.10 mag./kpc infra-red, corresponding to about 0.22 mag.!kpc in the photographic region. The unevenness in the surface distribution of M stars indicates local regions of much heavier obscuration. A density analysis has been made of 627 stars from Mo to M4. At a distance of 2 kpc from the sun the number of stars is 20 X 10-6 stars per cubic parsec. At 6 kpc a value of 8 X 10-6 is reached. These numbers vary slightly with different assumptions in absorption and absolute magnitude spread. Warner and Swasey Observatory, Case Institute of Technology, Cleveland, Ohio. Publication: The Astronomical Journal Pub Date: 1948 DOI: 10.1086/106157 Bibcode: 1948AJ.....54Q..46N full text sources ADS |

Colors of seven Cepheid variable stars in Cygnus.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Colors of seven Cepheid variable stars in Cygnus. Heyden, Francis J. Abstract Light curves of seven Cepheid variables in Cygnus, namely, V 386, MW, VY, BZ, TX, SZ and CD Cygni, have been determined in blue- photographic, photovisual and photored light from photometric plates taken at the Harvard Oak Ridge Station. The mean light-curves were derived from observations taken during the summers of 1944 and 1945. Two telescopes were used so that each yellow or red plate was taken simultaneously with a blue one. Color curves showing the variation of the blue- yellow and the blue-red color indices have been derived from the mean light-curves for each of the seven stars. These color curves show a definite correlation with the spectral curves which have been prdvided for this program by Dr. Struve of Yerkes Observatory. Color excesses from the blue-yellow color indices are based on the difference between the observed color index at minimum light and provisional normal color indices for stars of luminosity class Ib in the Morgan, Keenan and Kellman system. These normal colors were prepared by Miss Hagopian at Harvard Observatory. The color index at minimum light was selected because Struve has found1 the spectra nearest to normal at that part of the light curve. Total photographic absorptions have been computed by multiplying the color excesses b the factor 5. This factor is perhaps too large. The distance of the stars have been computed from the median absolute magnitude taken from Dr. Shapley `S photographic period-luminosity curve, from the median apparent magnitude of the blue light-curves and from the total photographic absorption. The formula used was: 5 log r = m - M - A $ 5. The following table contains a summarN' of the results. Variable m Sp. M c.E. A Distance (Cygni) (pg) (MKK) (pg) (mag) (pg) (parsecs) V386 11.00 GI -1.53 0.91 4.55 395 MW 10.60 GI -1.64 0.61 3.05 689 VY 10.60 GI -1.85 0.71 3.55 603 BZ 11.75 G -2.02 o.8o 4.00 900 TX 11.25 G6 -2.32 0.93 4.65 6o8 SZ 10.75 Ko -2.33 0.50 2.50 1308 CD 10.00 Ko -2.42 0.10 0.50 2421 The total absorptions found for these seven stars agree very well with those estimated by F. Miller2 from star counts in the obscured regions near the North American nebula, and by Oort and Oosterhoff3 from the colors of fotir Cepheids in the Cygnus star cloud. I.Observamry, 65, 257, 1944. 2.Ann. Harv. Colt. Obs. 105, 316, 1936. 3.B. A. N. 9, 325, 1942. Georgetown College Observatory, Washington, D. C. Publication: The Astronomical Journal Pub Date: July 1946 DOI: 10.1086/105900 Bibcode: 1946AJ.....52...44H full text sources ADS |

The New Star in Cygnus

THE new star in Cygnus, the third discovered in that constellation, and therefore designated Nova Cygni III., was of magnitude 3.5 when first observed by Mr. Denning on August 20, but is now very faint, being below 9th magnitude. It is still visible in small telescopes, but requires large instruments for spectroscopic investigation.

The New Star in Cygnus

The New Star in Cygnus

The New Star in Cygnus

The New Star in Cygnus

The New Star in Cygnus

This object continued to brighten until the night of August 23, when it attained the second magnitude; since that date the decline of lustre has been considerable, and on August 29 I estimated the magnitude as 3.9.

A New Star in Centaurus1

A NEW star in the constellation Centaurus was found by Mrs. Fleming on December 12, 1895, from examination of the Draper Memorial photographs. Its approximate position for 1900 is in R.A. I3h. 34˙3m., Dec.–31° 8′. Attention was called to it from the peculiarity of the spectrum on a plate taken at Arequipa on July 18, 1895, with the Bache Telescope, exposure 52 mins. The spectrum resembles that of the nebula surrounding 30 Doradus, and also that of the star A.G.C. 20937, and is unlike that of an ordinary nebula or of the new stars in Auriga, Norma, and Carina. This object is very near the nebula N.G.C. 5253, which follows 1˙28s., and is north 23″. No trace of it can be found on 55 plates taken from May 21, 1889, to June 14, 1895, inclusive. On July 8, 1895, it appeared on a chart plate, and its magnitude was 7˙2. On a plate taken July 10, 1895, its magnitude was also 7˙2. On Decem ber 16, 1895, a faint photographic image of it, magnitude 10˙9, was obtained with the 11-inch Draper Telescope, although it was very low, faint, and near the sun. On this date, and on December 19, it was also seen by Mr. O. C. Wendell with the 15-inch Equatorial as a star of about the eleventh magnitude. An examination with a prism showed that the spectrum was monochromatic, and closely resembled that of the adjacent nebula. Although the spectrum is unlike those of the new stars in Auriga, Norma, and Carina, yet this object is like them in other respects. All were very faint or invisible for several years preceding their first known appearance. They suddenly-attained their full brightness and soon began to fade. Like the new stars in Cygnus, Auriga, and Norma, this star appears to have changed into a gaseous nebula.

Our Astronomical Column

BRIGHT-LINE STARS.—Exact information about stars with bright lines in their spectra is appreciated by all who have the advance of celestial science at heart. In a paper in the June number of Astronomy and Astro-Physics, Prof. W. W. Campbell brings together all that is known with regard to objects of this spectroscopic character, and adds to the literature a number of important observations made by himself. Since 1867, when MM. Wolf and Rayet discovered three bright-line stars in Cygnus, fifty-two objects of the same type have been found, forty-two of this number being placed to the credit of the Harvard College Observatory.

IV. On Wolf and Rayet's bright-line stars in Cygnus

In 1867 MM. Wolf and Rayet discovered at the Paris Observatory three small stars in Cygnus, which in the spectroscope showed several bright lines upon a continuous spectrum. All three stars have a very bright band in the blue part of the spectrum. These stars are: –B. D. + 35°, No. 4001. B. D. + 35°, No. 4013. B. D. + 36°, No. 3956.

Two probable variable and seven possibly variable stars in Cygnus

Two probable variable and seven possibly variable stars in Cygnus

Note on Photographs of Stars in Cygnus taken in August 1886

Note on Photographs of Stars in Cygnus taken in August 1886

Draper Memorial Photographs of Stellar Spectra Exhibiting Bright Lines

THE spectra of ordinary stars, whether examined directly by the eye, or indirectly by means of photography, present little variety. The comparatively few cases of deviation from the usual type are therefore particularly interesting, and the occurrence of bright lines in a stellar spectrum constitutes perhaps the most singular exception to the general rule. The brightness of the F line in the spectra of γ Cassiopeiæ and β Lyræ was noticed by Secchi. Rayet afterwards found three rather faint stars in Cygnus, the light of which was largely concentrated in bright lines or bands. The adoption at the Harvard College Observatory of a system of sweeping, with a direct-vision prism attached to the eye-piece of the equatorial telescope, resulted in the discovery by the present writer of several additional objects of the same class. Still more recently, Dr. Copeland, during a journey to the Andes, has extended the list by the dis covery of some similar stars in the southern heavens.

The New Variable Red Star in Cygnus (1855.0 20h 36m38s + 47° 37.5)

Astronomische NachrichtenVolume 101, Issue 11 p. 176-176 Article The New Variable Red Star in Cygnus (1855.0 20h 36m38s + 47° 37.5) J. Birmingham, J. Birmingham Millbrook, TuamSearch for more papers by this author J. Birmingham, J. Birmingham Millbrook, TuamSearch for more papers by this author First published: 1882 https://doi.org/10.1002/asna.18821011109AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume101, Issue111882Pages 176-176 RelatedInformation

The New Red Star in Cygnus

THE above star, which I found on the 22nd of May last, and which then appeared of the 9th magnitude, and reached 8 m. on June 8, seems now no more than 12 m. Estimations of very small magnitudes are, of course, very difficult, but I believe I am not under the mark in saying 12 m., as I found the star not easy with a 41/2.inch O.G. At the same time its deep crimson seemed very striking by glimpses, and in its present state it if, perhaps, the smallest among the stars whose red colour has been observed. It will probably have to be classed among the most remarkable variables.

The Star Oeltzen, 17681

THE star Oeltzen, 17681, whose spectrum was announced by me to consist mainly of a yellow and blue band (NATURE, vol. xxii. p. 483), proves to belong to the same class as the three stars in Cygnus discovered by Wolf and Rayet in 1867 (Comptes rendus, vol. lxv. p. 292). A curious feature of these spectra is that they resemble each other without being identical, the relative brightness of the lines being very different. A further study of them is much to be desired.

Observations of the new Variable Red Star in Cygnus (A. N. 2377)

Astronomische NachrichtenVolume 100, Issue 5 p. 75-76 Article Observations of the new Variable Red Star in Cygnus (A. N. 2377) J. Birmingham, J. Birmingham Markree, Co. Sligo, IrelandSearch for more papers by this authorDoctor Doberck, Doctor Doberck Markree, Co. Sligo, IrelandSearch for more papers by this author J. Birmingham, J. Birmingham Markree, Co. Sligo, IrelandSearch for more papers by this authorDoctor Doberck, Doctor Doberck Markree, Co. Sligo, IrelandSearch for more papers by this author First published: 1881 https://doi.org/10.1002/asna.18811000506AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume100, Issue51881Pages 75-76 RelatedInformation