Contingut
Imatges
Carregar la teva Imatge
DSS Images Other Images
Articles Relacionats
Interstellar TiII in the Milky Way and Magellanic Clouds
We discuss several sets of TiII absorption-line data, which probe avariety of interstellar environments in our Galaxy and in the MagellanicClouds. Comparisons of high-resolution [full width at half-maximum(FWHM) ~ 1.3-1.5kms-1] TiII spectra of Galactic targets withcorresponding high-resolution spectra of NaI, KI and CaII reveal bothsimilarities and differences in the detailed structure of theabsorption-line profiles - reflecting component-to-component differencesin the ionization and depletion behaviour of those species.Moderate-resolution (FWHM ~ 3.4-4.5kms-1) spectra of moreheavily reddened Galactic stars provide more extensive information onthe titanium depletion in colder, denser clouds - where more than 99.9per cent of the Ti may be in the dust phase. Moderate-resolution (FWHM ~4.5-8.7kms-1) spectra of stars in the Magellanic Cloudssuggest that the titanium depletion is generally much less severe in theLarge and Small Magellanic Clouds than in our Galaxy [for a givenN(Htot), E(B - V), or molecular fraction f(H2)] -providing additional evidence for differences in depletion patterns inthose two lower-metallicity galaxies. We briefly discuss possibleimplications of these results for the interpretation of gas-phaseabundances in quasi-stellar object absorption-line systems and ofvariations in the D/H ratio in the local Galactic interstellar medium.This paper is based in part on observations collected at the EuropeanSouthern Observatory, Chile, under programmes 65.I-0526, 67.C-0281,67.D-0238, 70.D-0164, 72.C-0682 and 74.D-0109. Based in part onobservations made with the NASA/ESA Hubble Space Telescope, obtainedfrom the data archive at the Space Telescope Science Institute. STScI isoperated by the Association of Universities for Research in Astronomy,Inc. under NASA contract NAS5-26555.Visiting observer, European Southern Observatory and Kitt Peak NationalObservatory. ‡E-mail: dwelty@astro.illinois.edu (DEW); Paul.crowther@sheffield.ac.uk(PAC)
| Properties and Origin of the High-Velocity Gas Toward the Large Magellanic Cloud
In the spectra of 139 early-type Large Magellanic Cloud (LMC) starsobserved with Far Ultraviolet Spectroscopic Explorer and with deep radioParkes H I 21 cm observations along with those stars, we search for andanalyze the absorption and emission from high-velocity gas at +90 <=v LSR <= +175 km s–1. The H I columndensity of the high-velocity clouds (HVCs) along these sightlines rangesfrom <1018.4 to 1019.2 cm–2.The incidence of the HVC metal absorption is 70%, significantly higherthan the H I emission occurrence of 32%. We find that the meanmetallicity of the HVC is [O I/H I] = –0.51 ±0.12 0.16. There is no strong evidence for a largevariation in the HVC metallicity, implying that these HVCs have asimilar origin and are part of the same complex. The mean and scatter ofthe HVC metallicities are more consistent with the present-day LMCoxygen abundance than that of the Small Magellanic Cloud or the MW. Wefind that on average [Si II/O I] = +0.48 ± 0.150.25 and [Fe II/O I] = +0.33 ± 0.140.21, implying that the HVC complex is dominantly ionized.The HVC complex has a multiphase structure with neutral (O I, Fe II),weakly ionized (Fe II, N II), and highly ionized (O VI) components, andhas evidence of dust but no molecules. All the observed properties ofthe HVC can be explained by an energetic outflow from the LMC. This isthe first example of a large (>106 M sun) HVCcomplex that is linked to stellar feedback occurring in a dwarf spiralgalaxy.Based on observations made with the NASA-CNES-CSA Far UltravioletSpectroscopic Explorer. FUSE is operated for NASA by the Johns HopkinsUniversity under NASA contract NAS5-32985. Based on observations madewith the NASA/ESA Hubble Space Telescope, obtained at the SpaceTelescope Science Institute, which is operated by the Association ofUniversities for Research in Astronomy, Inc. under NASA contract No.NAS5-26555. Based on observations made by the Parkes telescope. TheParkes telescope is part of the Autralia Telescope, which is funded bythe Commonwealth of Australia for operation as a National Facilitymanaged by CSIRO.
| A FUSE Survey of the Rotation Rates of Very Massive Stars in the Small and Large Magellanic Clouds
We present projected rotational velocity values for 97 Galactic, 55 SMC,and 106 LMC O-B type stars from archival FUSE observations. The evolvedand unevolved samples from each environment are compared through theKolmogorov-Smirnov test to determine if the distribution of equatorialrotational velocities is metallicity dependent for these massiveobjects. Stellar interior models predict that massive stars with SMCmetallicity will have significantly reduced angular momentum loss on themain sequence compared to their Galactic counterparts. Our results findsome support for this prediction but also show that even at Galacticmetallicity, evolved and unevolved massive stars have fairly similarfractions of stars with large Vsin i values. Macroturbulent broadeningthat is present in the spectral features of Galactic evolved massivestars is lower in the LMC and SMC samples. This suggests the processesthat lead to macroturbulence are dependent upon metallicity.
| The Far Ultraviolet Spectroscopic Explorer Legacy in the Magellanic Clouds: An Online Stellar Sight Line Atlas
We present an atlas of stellar sight line data from the Far UltravioletSpectroscopic Explorer (FUSE) satellite for 287 stars in the MagellanicClouds, obtained from eight years of satellite operations. The intent ofour project is to make this rich ensemble data set accessible to a broadcommunity of researchers in a standardized format that will enable easyidentification of subsets of these data that are appropriate forpursuing specific science programs. We present the data in astandardized manner, showing key interstellar lines on a velocity scale,optical (MCELS) and infrared (Spitzer) sight line context images, andoverview plots of the spectral region containing the O VI??1032, 1038 doublet, and the entire 905-1187 Åspectral range observed with FUSE. Objects with multiple observationshave had their data summed to directly provide the highestsignal-to-noise ratio available. These data are accessible online as aHigh Level Science Product through the Multimission Archive at SpaceTelescope (MAST). In this article, we describe the data sets andprocessing, the atlas materials, and the MAST interface in detail, andalso provide examples of how to use these materials.
| The Large Magellanic Cloud: diffuse interstellar bands, atomic lines and the local environmental conditions
The Large Magellanic Cloud (LMC) offers a unique laboratory to study thediffuse interstellar bands (DIBs) under conditions that are profoundlydifferent from those in the Galaxy. DIB carrier abundances depend onseveral environmental factors, in particular the local UV radiationfield. In this paper we present measurements of twelve DIBs in fivelines of sight to early-type stars in the LMC, including the 30Doradus region. From the high resolution spectra obtained withVLT/UVES we also derive environmental parameters that characterise thelocal interstellar medium (ISM) in the probed LMC clouds. These includethe column density components (including total column density) for theatomic resonance lines of Na I, Ca II, Ti II, K I. In addition, wederive the H I column density from 21 cm line profiles, thetotal-to-selective visual extinction RV and the gas-to-dustratio N(H I)/A_V. Furthermore, from atomic line ratios we derive theionisation balance and relative UV field strength in these environments.We discuss the properties of the LMC ISM in the context of DIB carrierformation. The behaviour of DIBs in the LMC is compared to that of DIBsin different local environmental conditions in the Milky Way. A keyresult is that in most cases the diffuse band strengths are weak (up tofactor 5) with respect to Galactic lines of sight of comparablereddening, EB-V. In the line of sight towards Sk -69223 the 5780 and 5797 Å DIBs are very similar instrength and profile to those observed towards HD144217, which is typical of an environment exposed to a strongUV field. From the velocity analysis we find that DIB carriers (towardsSk -69 243) are better correlated with the ionisedspecies like Ca II than with neutrals (like Na I and CO). The mostsignificant parameter that governs the behaviour of the DIB carrier isthe strength of the UV field.
| A Quantitative Comparison of the Small Magellanic Cloud, Large Magellanic Cloud, and Milky Way Ultraviolet to Near-Infrared Extinction Curves
We present an exhaustive quantitative comparison of all the knownextinction curves in the Small and Large Magellanic Clouds (SMC and LMC)with our understanding of the general behavior of Milky Way extinctioncurves. The RV-dependent CCM relationship of Cardelli,Clayton, and Mathis and the sample of extinction curves used to derivethis relationship are used to describe the general behavior of Milky Wayextinction curves. The ultraviolet portion of the SMC and LMC extinctioncurves are derived from archival IUE data, except for one new SMCextinction curve, which was measured using Hubble Space Telescope SpaceTelescope Imaging Spectrograph observations. The optical extinctioncurves are derived from new (for the SMC) and literature UBVRIphotometry (for the LMC). The near-infrared extinction curves arecalculated mainly from 2MASS photometry supplemented with DENIS and newJHK photometry. For each extinction curve, we giveRV=A(V)/E(B-V) and N(H I) values that probe the same dustcolumn as the extinction curve. We compare the properties of the SMC andLMC extinction curves with the CCM relationship three different ways:each curve by itself, the behavior of extinction at differentwavelengths with RV, and the behavior of the extinction curveFitzpatrick and Massa fit parameters with RV. As has beenfound previously, we find that a small number of LMC extinction curvesare consistent with the CCM relationship, but the majority of the LMCand all the SMC curves do not follow the CCM relationship. For the firsttime, we find that the CCM relationship seems to form a bound on theproperties of all the LMC and SMC extinction curves. This resultstrengthens the picture dust extinction curves exhibit of a continuum ofproperties between those found in the Milky Way and the SMC bar.Tentative evidence based on the behavior of the extinction curves withdust-to-gas ratio suggests that the continuum of dust extinction curvesis possibly caused by the environmental stresses of nearby starformation activity.Partially based on observations made with the NASA/ESA Hubble SpaceTelescope, obtained at the Space Telescope Science Institute, which isoperated by the Association of Universities for Research in Astronomy,Inc., under NASA contract NAS 5-26555. These observations are associatedwith proposal 8198.
| Far Ultraviolet Spectroscopic Explorer Snapshot Survey of O VI Variability in the Winds of 66 OB-Type Stars
We have used the Far Ultraviolet Spectroscopic Explorer to conduct asnapshot survey of O VI variability in the winds of 66 OB-type stars inthe Galaxy and the Magellanic Clouds. These time series consist of twoor three observations separated by intervals ranging from a few days toseveral months. Although these time series provide the bare minimum ofinformation required to detect variations, this survey demonstrates thatthe O VI doublet in the winds of OB-type stars is variable on variousscales in both time and velocity. For spectral types from O3 to B1, 64%vary in time. At spectral types later than B1, no wind variability isobserved. In view of the limitations of this survey, this fractionrepresents a lower limit on the true incidence of variability in the OVI wind lines, which is very common and probably ubiquitous. Incontrast, for S IV and P V, only a small percentage of the whole sampleshows wind variations, although this may be principally due to selectioneffects. The observed variations extend over several hundreds ofkilometers per second of the wind profile and can be strong. The widthover which the wind O VI profile varies is only weakly correlated withthe terminal velocity (v&infy;), but a significantcorrelation (close to a 1:1 relationship) is derived between the maximumvelocity of the variation and v&infy;. High-velocity O VIwind absorption features (possibly related to the discrete absorptioncomponents seen in other wind lines) are also observed in 46% of thecases for spectral types from O3 to B0.5. These features are variable,but the nature of their propagation cannot be determined from thissurvey. If X-rays can produce sufficient O VI by Auger ionization of OIV and the X-rays originate from strong shocks in the wind, this studysuggests that stronger shocks occur more frequently nearv&infy;, causing an enhancement of O VI nearv&infy;.
| Synthetic High-Resolution Line Spectra of Star-forming Galaxies below 1200 Å
We have generated a set of far-ultraviolet stellar libraries usingspectra of OB and Wolf-Rayet stars in the Galaxy and the Large and SmallMagellanic Cloud. The spectra were collected with the Far UltravioletSpectroscopic Explorer and cover a wavelength range from 1003.1 to1182.7 Å at a resolution of 0.127 Å. The libraries extendfrom the earliest O to late-O and early-B stars for the Magellanic Cloudand Galactic libraries, respectively. Attention is paid to the complexblending of stellar and interstellar lines, which can be significant,especially in models using Galactic stars. The most severe contaminationis due to molecular hydrogen. Using a simple model for the H2line strength, we were able to remove the molecular hydrogen lines in asubset of Magellanic Cloud stars. Variations of the photospheric andwind features of C III λ1176, O VI λλ1032, 1038, PV λλ1118, 1128, and S IV λλ1063, 1073, 1074are discussed as a function of temperature and luminosity class. Thespectral libraries were implemented into the LavalSB and Starburst99packages and used to compute a standard set of synthetic spectra ofstar-forming galaxies. Representative spectra are presented for variousinitial mass functions and star formation histories. The valid parameterspace is confined to the youngest ages of less than ~=10 Myr for aninstantaneous burst, prior to the age when incompleteness of spectraltypes in the libraries sets in. For a continuous burst at solarmetallicity, the parameter space is not limited. The suite of models isuseful for interpreting the rest-frame far-ultraviolet in local andhigh-redshift galaxies. Based on observations made with theNASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. FUSE is operatedfor NASA by the Johns Hopkins University under NASA contract NAS5-32985.
| Detection of Diffuse Interstellar Bands in the Magellanic Clouds
With the Ultraviolet Visual Echelle Spectrograph mounted at the VeryLarge Telescope, we have observed at unprecedented spectral resolutionthe absorption spectrum toward reddened stars in the Magellanic Cloudsover the wavelength range of 3500-10500 Å. This range covers thestrong transitions associated with neutral and charged large carbonmolecules of varying sizes and structures. We report the first detectionof diffuse interstellar bands (DIBs) at 5780 and 5797 Å in theSmall Magellanic Cloud and the variation of the 6284 Å DIB towardseveral targets in the Large Magellanic Cloud. The variation of DIBs inthe Magellanic Clouds compared with Galactic targets may be governed bya combination of the different chemical processes prevailing inlow-metallicity regions and the local environmental conditions. Based onobservations made at the European Southern Observatory, Paranal, Chile(ESO program 67.C-0281).
| An Atlas of Far Ultraviolet Spectroscopic Explorer Sight Lines toward the Magellanic Clouds
We present an atlas of 57 Large Magellanic Cloud (LMC) and 37 SmallMagellanic Cloud (SMC) observations obtained with the Far UltravioletSpectroscopic Explorer (FUSE) satellite. The atlas highlights 12interstellar absorption-line transitions at a resolution of ~15 kms-1. These transitions cover a broad range of temperatures,ionization states, and abundances. The species included are O VI, whichprobes hot (T~3×105 K) ionized gas; C III and Fe III,which probe warm (T~104 K) ionized gas; Si II, P II, C II, FeII, and O I, which probe warm neutral gas; and six different molecularhydrogen transitions, which trace cold (T<=500 K) gas. We includeSchmidt Hα CCD images of the region surrounding each sight lineshowing the morphology of warm ionized gas in the vicinity, along withcontinuum images near each FUSE aperture position. We present severalinitial scientific results derived from this dataset on the interstellarmedium of the Magellanic Clouds and Galactic halo. O VI absorption atMagellanic Cloud velocities appears along nearly all sight lines,regardless of optical emission-line morphology. The velocity field ofLMC disk material is probed using P II λ1152.8 absorption and isseen to be consistent with recent H I results. While the velocitystructure of the SMC is complex, two absorption features are clearlyseparated in the SMC data-a strong absorption complex between +100 and+130 km s-1, and a weaker feature near +180 kms-1. The velocity separation between these complexes varieswith position, being greater on average in the southwest portion of theSMC. A lower velocity absorption component seen the nine sight linestoward the bright H II region N66 in the SMC may be the result of anoutflow or an old SNR within this nebular complex. Absorption in Fe IIand O I at ~+60 km s-1 and ~+120 km s-1 appearalong many LMC sight lines. They are attributed, respectively, to anintermediate-velocity cloud and a high-velocity cloud in the Milky Wayhalo. Both features are dramatically stronger toward the eastern half ofthe LMC and are not correlated with each other or with LMC Hαmorphology. The lower velocity of the SMC and broader absorption linescomplicate the detection of intermediate and high velocity Galacticabsorption along SMC sight lines. This work contains data obtained forthe Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated bythe Johns Hopkins University. Financial support has been provided byNASA contract NAS 5-32985.
| A Reanalysis of the Ultraviolet Extinction from Interstellar Dust in the Large Magellanic Cloud
We have reanalyzed the Large Magellanic Cloud's (LMC) ultraviolet (UV)extinction using data from the IUE final archive. Our new analysis takesadvantage of the improved signal-to-noise ratio of the IUE NEWSIPSreduction, the exclusion of stars with very low reddening, the carefulselection of well-matched comparison stars, and an analysis of theeffects of Galactic foreground dust. Differences between the averageextinction curves of the 30 Dor region and the rest of the LMC arereduced compared with previous studies. We find that there is a group ofstars with very weak 2175 Å bumps that lie in or near the regionoccupied by the supergiant shell, LMC 2, on the southeast side of 30Dor. The average extinction curves inside and outside LMC 2 show a verysignificant difference in 2175 Å bump strength, but their far-UVextinctions are similar. While it is unclear whether or not theextinction outside the LMC 2 region can be fitted with the relation ofCardelli, Clayton, & Mathis (CCM), sight lines near LMC 2 cannot befitted with CCM because of their weak 2175 Å bumps. While theextinction properties seen in the LMC lie within the range of propertiesseen in the Galaxy, the correlations of UV extinction properties withenvironment seen in the Galaxy do not appear to hold in the LMC.
| The HIPPARCOS proper motion of the Magellanic Clouds
The proper motion of the Large (LMC) and Small (SMC) Magellanic Cloudusing data acquired with the Hipparcos satellite is presented. Hipparcosmeasured 36 stars in the LMC and 11 stars in the SMC. A correctlyweighted mean of the data yields the presently available most accuratevalues, mu_alpha cos(delta) = 1.94 +/- 0.29 mas/yr, mu_delta = - 0.14+/- 0.36 mas/yr for the LMC. For the SMC, mu_alpha cos(delta) = 1.23 +/-0.84 mas/yr, mu_delta = - 1.21 +/- 0.75 mas/yr is obtained, whereby careis taken to exclude likely tidal motions induced by the LMC. Bothgalaxies are moving approximately parallel to each other on the sky,with the Magellanic Stream trailing behind. The Hipparcos proper motionsare in agreement with previous measurements using PPM catalogue data byKroupa et al. (1994), and by Jones et al. (1994) using backgroundgalaxies in a far-outlying field of the LMC. For the LMC the Hipparcosdata suggest a weak rotation signal in a clockwise direction on the sky.Comparison of the Hipparcos proper motion with the proper motion of thefield used by Jones et al. (1994), which is about 7.3 kpc distant fromthe center of the LMC, also suggests clockwise rotation. Combining thethree independent measurements of the proper motion of the LMC and thetwo independent measurements of the proper motion of the SMC improvesthe estimate of the proper motion of the LMC and SMC. The correspondinggalactocentric space motion vectors are computed. Within theuncertainties, the LMC and SMC are found to be on parallel trajectories.Recent theoretical work concerning the origin of the Magellanic Systemis briefly reviewed, but a unique model of the Magellanic Stream, forthe origin of the Magellanic Clouds, and for the mass distribution inthe Galaxy cannot yet be decided upon. Future astrometric space missionsare necessary to significantly improve our present knowledge of thespace motion of the two most conspicuous galactic neighbours of theMilky Way.
| Evidence for processed material in the atmospheres of Large Magellanic Cloud B supergiants
We present a high-dispersion study of the optical spectra of 11 LMCB-type supergiants. These stars had been shown previously to have a widerange in nitrogen absorption line strengths, despite having very similartemperatures and luminosities. The current study shows that therelatively rare nitrogen-weak stars also have weaker photospheric heliumlines and stronger photospheric oxygen lines than the morespectroscopically typical supergiants. This pattern suggests that thevast majority of LMC B-type supergiants have had their surfacescontaminated by material from their original hydrogen-burning cores -with a resultant enhancement of surface nitrogen and helium and adepletion in oxygen - while the spectroscopically nitrogen-weak starsare more likely to have retained their main-sequence surface abundances.
| A spectroscopic survey of B supergiants in the Large Magellanic Cloud
The results of a low-dispersion digital optical spectral survey of about100 B-type supergiants in the Large Magellanic Cloud are presented. TheMK spectral classification framework for B supergiants has beentransferred to the metal-weak LMC stars, and recommended classificationstandards have been designated. Variations among the metal linestrengths are examined. The most extreme variations are found for thenitrogen lines, for which a range of a factor of 3 or more may be seenin the equivalent widths within some spectral subclasses. It issuggested that these variations indicate a range of nitrogen surfaceabundances among the B supergiants, resulting from contamination of someof the stellar surfaces by processed material from the originalH-burning core.
| The properties of OB supergiants in the Large Magellanic Cloud. II - Spectral types and intrinsic colors
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1988ApJ...335..703F&db_key=AST
| Interstellar dust in the Large Magellanic Cloud
The results of observations from the IUE satellite and Las Campanas60-cm telescope of the physical characteristics of interstellar dust inthe Large Magellanic Cloud (LMC) are presented. Extinction andpolarization analysis of 12 reddened stars in the LMC showed dustcharacteristics in the optical and infrared regions similar to those ofGalactic dust. The derived wavelength dependences of polarization andpolarization efficiency were found to be comparable to Galactic values.The dust-to-gas ratios of the NH and CNO in the LMC were several timeslower than Galactic values. The relationship between the ultravioletextinction properties and heavy element abundances in the Galaxy, LMC,and the Small Magellanic Cloud (SMC) are discussed.
| On the photometric differences between luminous OBA type stars in the LMC with and without P Cygni characteristics
A comparison is presented of the photometric characteristics of O to A0stars of high luminosity in the Large Magellanic Cloud which exhibit ordo not exhibit P Cygni characteristics. VBLUW observations were made of29 OBA stars and 15 OBA stars with P Cygni characteristics (OBA/PC/stars). Examination of the three two-color diagrams in the systemindicates that the OBA(PC) stars are slightly bluer than the OBA stars,which may be explained by a higher luminosity for the OBA(PC) stars at agiven temperature. Computations of the free-free emission from theextended envelopes of OBA(PC) stars show the contribution of suchemission to the spectral energy distribution to be negligible in theabsence of extreme conditions in the shell. Comparison of observed withtheoretical colors reveals the reddening in OBA(PC) stars to be on theaverage 0.07 magnitudes greater than in OBA stars. Results suggest thatOBA supergiants start to exhibit P Cygni characteristics when the massloss rate becomes greater than or equal to 2 x 10 to the -6th solarmass/year.
| Radial velocities from objective-prism plates in the direction of the Large Magellanic Cloud
A catalog is presented of 711 Large Magellanic Cloud (LMC) stars, withattention to the radial velocities of 418 of these. Also given are theradial velocities of 1127 galactic stars in the direction of the LMC, aswell as discussions of the precision of these measurements and of radialvelocity dispersion in different fields.
| The gas to dust ratio and the near-infrared extinction law in the Large Magellanic Cloud
The interstellar Lyman-alpha absorption-profile in the LMC is presentedto show that the gas-to-color excess ratio in the LMC is approximatelyfour times larger than the Galactic value. The gas to dust ratio in theLMC derived from the profile is N(H I)/E(B-V) = 2 x 10 to the 22ndatoms/sq cm/mag, and near infrared photometry in the J, H and K bands ofthe early-type supergiants used for the profile is used to check if thisdust deficiency can be explained by an anomalous large grain sizedistribution. It is found that the near infrared reddening law in theLMC is similar to the Galactic law, and thus the high gas to dust ratioshould still hold if expressed as a ratio by mass.
| Ultraviolet interstellar extinction in the large Magellanic Cloud using observations with the International Ultraviolet Explorer
Ten early-type supergiants in the Large Magellanic Cloud (LMC) have beenobserved with the International Ultraviolet Explorer (IUE). The spectra(1150-3200 A) are shown, and their photometric properties are discussed.It is confirmed that the LMC interstellar extinction law for these starsdeviates significantly from the average galactic law in the sense thatthe 2200 A feature is deficient in strength and that, in thefar-ultraviolet (wavelength less than 2000 A), the observed LMCextinction law is significantly above the galactic curve.
| UBV photometry for supergiants of the Large Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1975A&A....43..345B&db_key=AST
| Radial velocities from objective-prism plates in the direction of the Large Magellanic Cloud. List of 398 stars, LMC members. List of 1434 galactic stars, in the LMC direction
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974A&AS...13..173F&db_key=AST
| Rotation et masse DU grand nuage de Magellan.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973A&A....28..165P&db_key=AST
| Spectrographic and photometric observations of supergiants and foreground stars in the direction of the Large Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1972A&AS....6..249A&db_key=AST
| BVRI-Photometry of the Brightest Stars in the Magellanic Clouds
We have made photometric observations in the BVRI system of 100 objectsthat belong to the Magellanic Clouds. The observational data indicate atleast two remarkable differences between some of the Magellanic Cloudobjects and the supergiant stars in the Galaxy, namely, the former aremore luminous than the most luminous galactic supergiants and they alsohave a color excess in V-R unexplained by interstellar extinction alone.Two possible explanations are likely for the additional color excess;either the presence of a circumstellar dust envelope or a differentchemical atmospheric composition from galactic supergiant stars, orperhaps both of them.
| Five-colour photometry of supergiants and the dust-to-gas ratio in the Large Magellanic Cloud.
Abstract image available at:http://adsabs.harvard.edu/abs/1970A&A.....7...49V
| A deep objective-prism survey for Large Magellanic Cloud members
Not Available
| Grand Nuage de Magellan. Liste des etoiles membres DU Grand Nuage de Magellan et liste d'etoiles galactiques
Not Available
| Equivalent widths of Hγ in stellar spectra of the Magellanic Clouds
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1966MNRAS.132..433H&db_key=AST
| Vitesses radiales dans la direction du Grand Nuage de Magellan
Not Available
|
Enviar un nou article
Enllaços Relacionats
- - No s'ha trobat enllaços -
Enviar un nou enllaç
Membre dels grups següents:
|
Dades d'Observació i Astrometria
| Constel·lació: | Mensa |
| Ascensió Recta: | 05h51m20.76s |
| Declinació: | -70°17'09.2" |
| Magnitud Aparent: | 11.544 |
| Moviment propi RA: | 0.9 |
| Moviment propi Dec: | 2.1 |
| B-T magnitude: | 11.372 |
| V-T magnitude: | 11.53 |
Catàlegs i designacions:
|
INHABITED SKY
