Hα Emission Stars Research Articles

A Large Number of Herbig-Haro Candidates Found by the Contrast Enhancement and Unsharp Masking Technique

AbstractAbout 1300, 60 and 70 Herbig-Haro candidates have been picked up in the Ori A/L1641, Ori B/L1630 and NGC 2264/Mon OBI regions, respectively, on deep Schmidt plates. The contrast enhancement and unsharp masking technique has been applied simultaneously. Unsharp masking applied to an objective-prism Schmidt plate for the Carina Nebula region has yielded the detection of 38 Hα emission stars, of which 13 are new findings.

Emission-Line Stars in the Outer Part of the Orion Star-Forming Region

In a series of emission-line star survey programs we have conducted wide and deep survey observations for Hα emission stars in the Orion star-forming region. The first result for the Kiso area A-0904 (5°x5°, centered at α = 5h40m and δ = +0°) was presented in Paper I (Wiramihardja et al., 1989), followed by Paper II (Kogure et al., 1989) for the area A-0903 (α = 5h20m, δ = −5° and A-0976 (α = 5h40m, δ = −5°). In Paper IV the results for the areas A-1047 (α = 5h20m, δ = −10° and A-1048 (α = 5h40m, δ = −10°) are given.

A Wide and Deep Survey of Emission-line Stars in the Orion Region

AbstractWe have carried out an extensive survey of Hα emission stars in the Orion region over an area of about 100 deg2. We present the results for the areas A-0975 and A-0976 of about 25 deg2 each.

The physical properties of the Hα-emission line stars: CD-42°11721, KK Oph and XX Oph

By use of the data found in the literature, observed at the ESO and taken from the IRAS point source catalogue, the physical properties of the Hα-emission stars: CD-42°11721, KK Oph and XX Oph were studied photometrically and spectroscopically. The results can be summarized as follows: (a) Feii and [Feii] emission lines show that these stars have a gaseous envelope of which part is of low density. (b) P Cygni profiles in the spectral lines of XX Oph indicate the existence of rapid gaseous motions in its atmosphere. The presence of P Cygni profiles in the spectra of the other two stars is not certain. (c) In the outer atmosphere of CD-42°11721 and KK Oph at least two circumstellar concentrations of dust grains seems to be present; the temperatures of these dust shells are, for both stars, about 1200 and 250 K. (d) XX Oph has an M6III companion causing the infrared excess. Furthermore, we have studied the physical properties of the dust shells. The distances to the central star, the chemical composition and the masses of each shell were estimated. It is recommended to study above stars further with high dispersion spectroscopy and simultaneous long-term photometry.

Detection of T-Tauri Star Candidates in the Canis Major Star-Forming Region and its Implications

We have made a survey of Hα-emission stars in the CMa R1 region with the 105cm Schmidt telescope at the Kiso Observatory. In an area of about 37 square degrees, a total of 107 Hα-emission stars (V = 6-15 mag.) was found, and, for all of them, the photographic photometry in the UBV system has been carried out.

H? emission stars in the region of IC 1396

155 Hα emission stars not catalogued earlier have been detected with the 60/90/180 cm Schmidt telescope of Konkoly Observatory in a field of 19.5 square degrees centred on theHii region IC 1396.UBVR photohraphic magnitudes were obtained for most of them. Equatorial coordinates for the epoch 1950.0 as well as identification charts are given. Space distribution of the emission stars and their connection with the association Cepheus OB 2 are briefly discussed.

Cooperation in astronomy between Indonesia and Japan

The cooperation programme in astronomy between Indonesia and Japan is presented as an example of a well-coordinated bilateral cooperation between Asian countries. This cooperation has started in 1979, in the fields of galactic astronomy and stellar physics. The form of the cooperation is principally the exchange of persons between both countries for the purposes of collaborative works in some specific fields, the training of young astronomers, and technical cooperation. The main subjects of collaborative works are: (1) survey of red giants in the galactic center region, (2) survey of Hα-emission stars in some areas of the sky, (3) theoretical study of the dynamical evolution of stellar systems, (4) photoelectric observations of southern close binaries, (5) X-ray binaries and pulsars, (6) Be stars, and (7) other topics. The organization and main results of these works are presented, along with a future aspect of the cooperation.

Possible Groupings of Irregular (Orion) Variables

New groupings of Hα-emission stars connected with young clusters, associations and nebulae are considered to be possible regions of clusterings of irregular (Orion-type) variables. They are listed in Table I and an example, No. 19, is shown in Figure 1.

Hα-EMISSION Stars and Planetary Nebulae in the Vicinity of m8 and M20 and in VELA from L = 230° to 241° Along the Galactic Equator.

Hα-EMISSION Stars and Planetary Nebulae in the Vicinity of m8 and M20 and in VELA from L = 230° to 241° Along the Galactic Equator.

Catalogues of Hα-EMISSION Stars and Nebulae in the Magellanic Clouds.

Catalogues of Hα-EMISSION Stars and Nebulae in the Magellanic Clouds.

Hα-EMISSION Stars Associated with a Dark Lane in Lupus.

Hα-EMISSION Stars Associated with a Dark Lane in Lupus.

Hα Emission Stars and Peculiar Objects in the Orion Nebula.

view Abstract Citations (126) References (7) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Hα Emission Stars and Peculiar Objects in the Orion Nebula. Haro, Guillermo Abstract Two hundred and fifty-five stars showing emission in Ha have been observed in an area of 3.5 square degrees which contains the brightest part of the Orion Nebula. The distribution and frequency of these emission stars seem to be correlated with the general shape and differing intensity of the bright nebulosities of this region. At the same time the existence of a dense stellar group provisionally called the "Orion Nebula Cluster' `-centered at the Trapezium stars is strikingly revealed. Fourteen peculiar objects, most of them stars imbedded in nebulous material, have been found in the same area. One of these is probably a new faint cometary nebula. The apparent coexistence and concentricity observed between the Nebuia and the densest group of emission stars suggests a tentative hypothesis of the formation of late-type dwarf stars from the Orion nebular material. Publication: The Astrophysical Journal Pub Date: January 1953 DOI: 10.1086/145669 Bibcode: 1953ApJ...117...73H full text sources ADS | data products SIMBAD (270)

Six Peculiar Hα-EMISSION Stars.

Six Peculiar Hα-EMISSION Stars.

Emission line stars near H and chi Persei.

view Abstract Citations (8) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Emission line stars near H and chi Persei. Bidelman, William P. Abstract A plot of the known non-supergiant emission- line stars in the region of the double cluster in Perseus shows that there is a much more pronounced grouping of these objects about the cluster x Persei than about the other cluster. In view of the apparent similarity in constitution of the two clusters, this result is of considerable interest. The average absolute magnitude of these emission-line stars may be estimated at about -3.5, if it is assumed that they are associated with the double cluster; their spectral types, as far as known, range from Bo to B3. Two previously unrecognized Hα emission stars of early type have been found on an~objective prism plate of the h and x Persei region taken with the Schmidt-type reflector of the Warner and Swasey Observatory. This plate was made available to the writer through the kindness of the director of that observatory, Dr. J. J. Xassau. These new Be stars are BD +560612 and star number 2566 in Oosterhoff's monograph on the double cluster in Perseus. Yerkes Observatory, Williams Bay, Wis. Publication: The Astronomical Journal Pub Date: 1947 DOI: 10.1086/106002 Bibcode: 1947AJ.....52Q.121B full text sources ADS |

New Hα Emission Stars.

New Hα Emission Stars.