Carina Nebula 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.

High-resolution images of the dust and ionized gas distributions in the Carina Nebula

High-resolution images of the dust and ionized gas distributions in the Carina Nebula

Distribution of hot stars and interstellar dust in Carina

From the results of observations with the "Glazar" astronomical telescope of a region of Carina containing the Carina nebula we have studied the spatial distribution of 150 stars of early spectral classes. It is shown that in the direction of observation the law of interstellar absorption is normal. In the region under study five stellar associations of 0 type at distances about 1100, 2000, 3000, 4000, and 5000 pc were observed. At a near distance of 560 pc a group of stars of relatively late spectral classes (B3-B9) was observed. In this group a close system of stars consisting of five members was discovered. It is shown that three of the clusters located in this direction, NGC 3293, Bo 10, and IC 2581 (Cr 222) belong to the association Car OB 2.0 at a distance of about 2200 pc. Another cluster observed here, NGC 3324, seems to belong to the association Car OB 3.0 at a distance of about 2900 pc. It is shown that up to distances of about 1000 pc there is a layer of dust causing minimal absorption of radiation 1'?.5 at )~ 1640 A of the stars located beyond this layer. In the volume of observed stellar associations the dust is distributed very unevenly. In the space between the associations there is no dust. 1. Introduction. The authors [1] have presented the results of observations in the direction of the stellar association Car OB1 carried out using the "Glazar" astronomical telescope. On an area of the sky of approximately 13 square degrees 233 stars brighter than 8~.5 at )~ 1640 A were detected. All these stars are stars of earlier spectral classes. In the direction of the region being observed the visual ray passes along the arm of Carina to a depth of up to 5-6 kpc. This region contains the noteworthy Carina nebula (NGC 3372) together with the multiple star ~ Car and several stellar clusters--Tr 14, Tr 15, Tr 16, IC 2581 (Cr 222), NCG 3324 (Cr 225), Cr 228, Cr 232, Bo 10, Bo 11, and NGC 3293. The stellar association Car OB1 and part of the stellar association Car OB2 are also located here. This region has been intensively studied by many investigators, and widely differing values have been given for the distances of the stellar clusters and associations, from 2.0 kpc to 3.7 kpc [2-22]. The results of a study of the distribution of the OB-stars observed in the region of the Carina nebula are given in [23], where it is shown that four of the six stellar clusters that project onto the nebula are actually located inside the nebula and constitute a single complex. It was also shown that the law of interstellar absorption in the Carina nebula is anomalous.

On the extinction law in the Carina nebula

Using the results of observations of the Carina nebula made with the space telescope Glazar, it is shown that the extinction law for the nebula is abnormal and that there is a single OB star complex within the nebula at a distance of about 2200 pc. It is suggested that the observed distribution of OB stars in the nebula and also the appearance of the nebula itself is due to a specific structure of the absorbing clouds within the nebula, and that the absorbing clouds may have such structure as a result of an explosion in the center of the nebula.

New O-type stellar associations in Carina

view Abstract Citations (7) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS New O-Type Stellar ssociations in Carina Tovmasyan, G. M. ; Oganesyan, R. Kh. ; Epremyan, R. A. ; Huguenin, D. Abstract Five O-type stellar associations are discovered by observations with the Glazar space telescope at 1640 A in the region of Carina, including the Carina nebula. These stellar associations are at distances of about 1100, 2000, 3000, 4000, and 5600 pc from the sun. A group of comparatively late-type stars, a B association is detected at a distance of about 560 pc. One more B association seems to exist at 300 pc. It is shown that extinction law in regions outside of the Carina nebula is normal. Publication: The Astronomical Journal Pub Date: August 1993 DOI: 10.1086/116667 Bibcode: 1993AJ....106..627T Keywords: Nebulae; O Stars; Star Clusters; Data Reduction; Stellar Luminosity; Stellar Spectra; Astrophysics; STARS: EARLY-TYPE full text sources ADS | data products SIMBAD (5)

A system of OB stars in the Carina nebula

A system of OB stars in the Carina nebula

Intracluster dust polarization in the Carina Nebula

view Abstract Citations (20) References (21) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Intracluster Dust Polarization in the Carina Nebula Marraco, H. G. ; Vega, E. I. ; Vrba, F. J. Abstract New UBVRI polarimetric observation of 25 Carina Nebula-embedded stars, together with BV polarimetric observations of 60 additional stars from that nebula, are presently used in conjunction with polarimetric observations from the literature to model and subtract the foreground dust contribution in the color excess and the visual polarization. The intracluster dust component thus obtained is found to have a polarization efficiency lower than the maximum observed for the interstellar medium. This result is consistent with the anomalous extinction for this region. Publication: The Astronomical Journal Pub Date: January 1993 DOI: 10.1086/116424 Bibcode: 1993AJ....105..258M Keywords: Astronomical Photometry; Cosmic Dust; Nebulae; Optical Polarization; Ubv Spectra; Interstellar Matter; Star Clusters; Stellar Coronas; Astrophysics; DUST; EXTINCTION; PLANETARY NEBULAE: INDIVIDUAL: CARENA full text sources ADS | data products SIMBAD (82) CDS (1)

22-GHz continuum observations of the Carina nebula

The Carina nebula was observed at 22 GHz using the 13.7-m Itapetinga Radio Telescope. The radio structure of the Carina region shows three lobes running perpendicular to the Galactic plane, suggesting a large-scale configuration, such as separate spiral arms, to explain the radio features. In addition, a spectral index survey was carried out over the nebula which indicated several non-thermal regions. They were interpreted as due to an old supernova remnant in front of the nebula.

Radial velocities in the open cluster Trumpler 14

In this paper we present radial velocity measurements of probable members of Trumpler 14, a very young open cluster associated with the Carina Nebula. We have found 4 double-line spectroscopic binaries and 2 single-line spectroscopic binaries. We have succeeded in deriving orbital elements for the SB1s. All the binaries are of potential astrophysical interest and are worth further observational efforts.

Hard X-ray emission from the Carina Nebula

view Abstract Citations (19) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Hard X-Ray Emission from the Carina Nebula Koyama, Katsuji ; Asaoka, Ikuko ; Ushimaru, Naoko ; Yamauchi, Shigeo ; Corbet, Robin H. D. Abstract Hard X-rays above a few keV from the Carina nebula were observed with the Ginga satellite. The hard X-ray emission was found to originate in a region less than 0.15 deg radius from Eta Car. The X-ray spectrum can be described by emission from a thin hot plasma with a temperature of 4.1 keV. The intensity is consistent with the results of previous observations made with large field-of-view instruments, providing allowance is made for emission from the Galactic ridge; however, it is about twice as large as that obtained by the smaller field-of-view SSS on board the Einstein Observatory. At least some of the hard X-ray emission may be extended with a diameter of 0.1-0.3 deg. The X-ray flux from the Eta Car region shows no intensity variations on a time scale between several seconds and 10 yr at a level greater than 30 percent. Publication: The Astrophysical Journal Pub Date: October 1990 DOI: 10.1086/169256 Bibcode: 1990ApJ...362..215K Keywords: High Temperature Plasmas; Nebulae; Satellite Observation; Stellar Coronas; X Ray Sources; X Ray Spectra; Binary Stars; Field Of View; Heao 2; Milky Way Galaxy; Astrophysics; NEBULAE: INDIVIDUAL NAME: CARINA NEBULA; RADIATION MECHANISMS; X-RAYS: SOURCES; X-RAYS: SPECTRA full text sources ADS | data products SIMBAD (6)

Fractal dimensions of nebulae

We have tried to measure fractal dimensions of the Eta Carinae Nebula and the Vela Nebula using the photographic plates of the ESO - SRC catalogue. For the fractal dimension of the border of the diffuse gas in Eta Carinae we obtain values in the range 1.3 to 1.4. The filamentary structure of the Vela SNR is found to have a dimension of 1.2.

Far-Infrared (120--300 Micron) Observations of the Carina Nebula

view Abstract Citations (56) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Far-Infrared (120--300 Micron) Observations of the Carina Nebula Ghosh, S. K. ; Iyengar, K. V. K. ; Rengarajan, T. N. ; Tandon, S. N. ; Verma, R. P. ; Daniel, R. R. Abstract The Carina nebula has been observed in a am wavelength band with a 100 cm balloon-borr telescope, and maps have been generated with a spatial resolution of 1'. More than thirty compact sourc were detected in the 0.5 deg2 area scanned; many of these sources do not have IRAS Point Source Catalc counterparts. The diffuse emission accounts for nearly half of the total emission in our band. A compariso with the observations at other wavelengths shows that the far-infrared emission is well correlated with oth tracers of matter. The region appears to be rich in massive stars, and most of the compact far-infrared sourc are likely to be dust-gas clumps heated externally by these stars. Subject headings: infrared: sources nebulae: H ii regions - nebulae: individual (Carina) Publication: The Astrophysical Journal Pub Date: July 1988 DOI: 10.1086/166523 Bibcode: 1988ApJ...330..928G Keywords: INFRARED: SOURCES; NEBULAE: H II REGIONS; NEBULAE: INDIVIDUAL NGC NUMBER: NGC 3372; Balloon-Borne Instruments; Far Infrared Radiation; Infrared Astronomy; Infrared Telescopes; Nebulae; Clumps; Cosmic Dust; Diffuse Radiation; Giant Stars; Interstellar Gas; Spatial Resolution; Stellar Evolution; Astronomy full text sources ADS | data products SIMBAD (14)

The ratio of total to selective absorption in the Carina OB2 association

Several previous studies in and around the Great Carina nebula (NGC 3372) have strongly indicated an abnormal interstellar extinction law with a high ratio of total to selective absorptionR. In the present study, newUBV photometric data and accurate MK spectral-types of stars in the region of the Carina OB2 association are used to show that (1) Car OB2 is a genuine stellar association located at a distance of 3.2 kpc, and (2) the interstellar extinction law seems to be normal throughout most of the region. A representative value ofR = A v/E(B − V) = 3.0 is derived for Car OB2 from the variable extinction method.

An infrared study of the stellar population in the direction of the Carina nebula: NGC 3372

Surveys at 2μm have been used to identify the brightest members of the stellar population in the direction of the Carina nebula. Subsequent JHK photometry combined with low-resolution 2μm spectra has been used to separate likely members of the Tr14/16 clusters from the field star population. Several heavily reddened new members of the Tr14/16 association are identified, some of which may be at an earlier evolutionary stage compared to the visible cluster populations. The distribution of reddening material, deduced from background field star colour-excesses, is shown to closely agree with the distribution of neutral material indicated by the 12CO observations of de Graauw et al. An examination of the reddening law for the nebula shows it to be clearly anomalous and characterized by a unique value of R=AV/ E(B–V)=4.8. This anomaly extends to all stars studied. An alternative interpretation of the reddening law is demonstrated by normalizing the colour-excess ratios with respect to E(V–J) rather than E(B–V). This shows normal extinction longward of 0.55μm (V) and reduced extinction shortward of this wavelength. Normal extinction in the infrared is also deduced from the (J–H), (H– K) diagram for the background field stars. It is suggested that a mechanism for grain destruction must be operating in the Carina nebula to explain this result.

A 6 second periodic X-ray source in Carina

view Abstract Citations (55) References (8) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A 6 Second Periodic X-Ray Source in Carina Seward, F. D. ; Charles, P. A. ; Smale, A. P. Abstract A serendipitous source, 1E 1048.1-5937, was discovered during Einstein imaging observations of the Carina nebula. On July 13, 1979, this source had an intensity of 0.14 IPC counts/s, and the signal was 65 percent pulsed with a period of 6.44 s. An earlier observation failed to detect any source with strength greater than 1/10 the above signal. The source is therefore highly variable, perhaps transient. An Exosat observation of this source on June 20, 1985 confirmed the pulse period and refined the source position to an accuracy of 10 arcsec. On the basis of the position, the source is tentatively identified with a V = 19 optical counterpart. The X-ray spectrum is best fitted by a power law with photon index = 2.26 and a column density of 1.6 x 10 to the 22nd atoms/sq cm. The X-ray characteristics are consistent with an accretion-powered Be star binary. Publication: The Astrophysical Journal Pub Date: June 1986 DOI: 10.1086/164294 Bibcode: 1986ApJ...305..814S Keywords: B Stars; Variable Stars; X Ray Binaries; Exosat Satellite; X Ray Spectra; Astrophysics; STARS: BE; STARS: INDIVIDUAL ALPHANUMERIC: 1E 1048.1-5937; X-RAYS: BINARIES; X-RAYS: SOURCES full text sources ADS | data products SIMBAD (1)

Insect-eye, Fabry-Perot observations of the large-scale motions within the Carina nebula (NGC 3372, RCW 53)

On a obtenu des profils de la raie [OIII] 5007 A avec des rapports signal-bruit eleves, une grande resolution spectrale (≃50000), mais une faible resolution spatiale (≃3 min arc) le long de deux lignes de 34 et 74 pc de long dans la nebuleuse Carina. On note des preuves de la presence d'une enveloppe d'environ 70 pc de diametre en expansion radiale

The high-ionization and excited-state interstellar lines in the Carina Nebula - A giant H II region in absorption

The dominant component of the highly ionized and excited-state interstellar species seen in the ultraviolet toward stars within the Carina Nebula has been found to have a heliocentric radial velocity of about -30 km/s. This velocity is known to correspond to the near edge of the expanding H II region, as shown by the double optical nebular emission lines and the single He I lambda 3889 nebular absorption line. It is also seen as a (nondominant) component in both the optical and ultraviolet low-ionization interstellar lines, discussed previously. Hence, the Carina Nebula provides a clear case in which the principal high-ionization interstellar features are associated with the hot stars against which they are observed; and a considerable range of absorption lines can provide physical information about the H II region. Also, the weaker zero-velocity, line-of-sight component in the high-ionization species can be measured in this direction relatively free from confusion by the material associated with the stars. There is, in addition, a pervasive high-ionization feature with a velocity of -90 km/s in this region, which has the relatively large value of N(C IV)/N(Si IV) = 4.5.

Observations of 115 GHz CO Emission Towards the Carina Nebula

We have carried out a survey of the 115 GHz CO emission (J = 1→0 transition) towards the Carina nebula (NGC 3372) using the Epping 4 m radio telescope of the CSIRO Division of Radiophysics. Of all the molecules detected in the interstellar medium CO is perhaps the best tracer of molecular clouds. It is an abundant molecule (second only to H2) and its line emission at microwave frequencies occurs at relatively low excitation.

The open cluster Tr 14

New photoelectric UBVRI data for stars in the young open cluster Tr 14 in the Great Carina Nebula (NGC 3372) are presented. The two-color diagram separates clearly the member from the nonmember stars. Thus, the membership of about 39 stars is suggested. Those located in the compact core of the cluster, have smaller reddening dispersion than those around it. No star appears above the Main Sequence at the faint end of the color-magnitude diagram. A distance modulus ofV0−Mv=12.20±0.2 is obtained, which gives an age of about 5×106 yr. From only the photometry it is concluded to be slightly older than the nearby cluster Tr16.

The violent interstellar medium associated with the Carina nebula. I - The line of sight toward HD 93205

view Abstract Citations (35) References (59) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The violent interstellar medium associated with the Carina Nebula. I.The line of sight toward HD 93205. Laurent, C. ; Paul, J. A. ; Pettini, M. Abstract Four high velocity and two low velocity components have been identified by the analysis of interstellar absorption lines in high resolution spectra of HD 93205. The chemical composition and physical conditions of the different regions are discussed in light of UV, optical and radio observations, and the two main high velocity components are found to show different relative abundance patterns. Among the two low velocity components, one has been identified with the normal interstellar material in the disk of the Galaxy between the sun and the Carina nebula. Column densities of interstellar C IV and Si IV have been measured in this component, free from contamination by circumstellar material. The other low velocity component has been identified with the approaching part of the expanding ionized nebula around the Carina OB associations, and consists of a dense H II region in which the two O I fine structure lines originate. Publication: The Astrophysical Journal Pub Date: September 1982 DOI: 10.1086/160244 Bibcode: 1982ApJ...260..163L Keywords: Interstellar Matter; Interstellar Radiation; Nebulae; Abundance; Chemical Composition; Energy Budgets; H Ii Regions; Ionization; Milky Way Galaxy; Star Clusters; Supernovae; Ultraviolet Spectra; Astrophysics full text sources ADS | data products SIMBAD (3) MAST (1) INES (1)