Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
Does the 3.3 Micron Polycyclic Aromatic Hydrocarbon Emission Feature Require Ultraviolet Excitation?
Unidentified infrared bands (UIBs) have been observed in virtually everydusty astrophysical environment investigated. The UIB carrier must beabundant and ubiquitous. Strong evidence points to polycyclic aromatichydrocarbons as likely candidates, but the identification is notcomplete. Additional diagnostics are needed to further constrain the UIBcarrier, such as probing excitation sources ranging from UV-strong toUV-weak to determine the ``band gap'' of the UIB carrier. Observationsand models suggest that the UIBs can be found in sources with weak UVfields. To that end, we present new results of observing the 3.3 μmspectral region in six stars embedded in reflection nebulae and in sixVega-like stars. These objects have effective temperatures ranging from3500 to 12,000 K. Their environments include dust that should berelatively unprocessed (reflection nebulae) and dust that has mostlikely undergone significant processing (Vega-like) by the embeddedillumination source. Together with data from the literature, we have asample of 27 sight lines. Our analysis suggests that neither thestrength of the UV field impinging on the dust nor the effectivetemperature of the star is the determining factor in whether the 3.3μm UIB emission is present in an object. We found three detections ofthe 3.3 μm emission band, one in a Vega-type object, one in a HerbigAe/Be object, and one in a reflection nebula, and all with disks. Therole of disk geometry is likely to be important in revealing orobscuring the photodissociation regions from which the UIB emissionarises.
| Toward an adequate method to isolate spectroscopic families of diffuse interstellar bands
We divide some of the observed diffuse interstellar bands (DIBs) intofamilies that appear to have the spectral structure of single species.Three different methods are applied to separate such families, exploringthe best approach for future investigations of this type. Starting witha statistical treatment of the data, we found that statistical methodsby themselves give insufficient results. Two other methods of dataanalysis (`averaging equivalent widths' and `investigating the figureswith arranged spectrograms') were found to be more useful as tools forfinding the spectroscopic families of DIBs. On the basis of thesemethods, we suggest some candidates as `relatives' of 5780- and5797-Å bands.
| High-Resolution Observations of Interstellar Ca I Absorption-Implications for Depletions and Electron Densities in Diffuse Clouds
We present high-resolution (FWHM~0.3-1.5 km s-1) spectra,obtained with the AAT UHRF, the McDonald Observatory 2.7 m coudéspectrograph, and/or the KPNO coudé feed, of interstellar Ca Iabsorption toward 30 Galactic stars. Comparisons of the column densitiesof Ca I, Ca II, K I, and other species-for individual componentsidentified in the line profiles and also when integrated over entirelines of sight-yield information on relative electron densities anddepletions (dependent on assumptions regarding the ionizationequilibrium). There is no obvious relationship between the ratio N(CaI)/N(Ca II) [equal to ne/(Γ/αr) forphotoionization equilibrium] and the fraction of hydrogen in molecularform f(H2) (often taken to be indicative of the local densitynH). For a smaller sample of sight lines for which thethermal pressure (nHT) and local density can be estimated viaanalysis of the C I fine-structure excitation, the average electrondensity inferred from C, Na, and K (assuming photoionizationequilibrium) seems to be independent of nH andnHT. While the electron density (ne) obtained fromthe ratio N(Ca I)/N(Ca II) is often significantly higher than the valuesderived from other elements, the patterns of relative nederived from different elements show both similarities and differencesfor different lines of sight-suggesting that additional processesbesides photoionization and radiative recombination commonly andsignificantly affect the ionization balance of heavy elements in diffuseinterstellar clouds. Such additional processes may also contribute tothe (apparently) larger than expected fractional ionizations(ne/nH) found for some lines of sight withindependent determinations of nH. In general, inclusion of``grain-assisted'' recombination does reduce the inferred ne,but it does not reconcile the ne estimated from differentelements; it may, however, suggest some dependence of ne onnH. The depletion of calcium may have a much weakerdependence on density than was suggested by earlier comparisons with CHand CN. Two appendices present similar high-resolution spectra of Fe Ifor a few stars and give a compilation of column density data for Ca I,Ca II, Fe I, and S I.
| Observations of Rotationally Resolved C3 in Translucent Sight Lines
The rotationally resolved spectrum of theA1Πu<--X1Σ+g000-000 transition of C3, centered at 4051.6 Å, hasbeen observed along 10 translucent lines of sight. To interpret thesespectra, a new method for the determination of column densities andanalysis of excitation profiles involving the simulation and fitting ofobserved spectra has been developed. The populations of lower rotationallevels (J<=14) in C3 are best fitted by thermaldistributions that are consistent with the kinetic temperaturesdetermined from the excitation profile of C2. Just as in thecase of C2, higher rotational levels (J>14) ofC3 show increased nonthermal population distributions inclouds that have been determined to have total gas densities below ~500cm-3.
| Some Diffuse Interstellar Bands Related to Interstellar C2 Molecules
We have investigated the correlations between the equivalent widths of21 selected diffuse interstellar bands (DIBs) and the correspondinginterstellar column densities N(C2), N(CN), and N(CH), toward53 stars with color excesses 0.11<=E(B-V)<=1.99. The observationaldata were derived primarily from echelle spectra acquired at R=38,000 aspart of our extensive, continuing survey of the bands. All but six ofthe 53 final spectra show signal-to-noise ratios >=800 at 5780Å. The principal result presented here is that seven of the 21bands prove to be examples of ``the C2 DIBs,'' a class ofweak, narrow bands whose normalized equivalent widthsWλ(X)/Wλ (λ6196) are wellcorrelated specifically with N(C2)/E(B-V) via power laws. Incontrast, the similarly normalized equivalent widths of the 14 other,well-known DIBs analyzed here are uncorrelated, or weaklyanticorrelated, with N(C2)/E(B-V), to within theobservational uncertainties. Thus, the polyatomic molecule(s) presumedto cause these seven C2 DIBs may bear a direct chemicalrelation to C2 that is not shared by the polyatomic moleculesputatively responsible for the other 14 bands. The C2 DIBsalso show positive correlations with N(CN)/E(B-V) and N(CH)/E(B-V) inour particular sample of light paths, although generally with shallowerslopes in the case of N(CN) and with greater scatter in the case ofN(CH). Eleven additional C2 DIBs are also identified but arenot analyzed here. Among the 18 C2 DIBs identified, fourapparently have not been previously detected. The λ4963 band isgenerally the strongest of the 18 C2 DIBs, while theλ4734 band shows the most sensitive correlation withN(C2).Based on observations obtained with the Apache Point Observatory 3.5 mtelescope, which is owned and operated by the Astrophysical ResearchConsortium.
| Observations of C3 in Translucent Sight Lines
The A1Πu<--X1Σ+g transition of the simplestpolyatomic carbon chain molecule, C3, at 4051.6 Å hasbeen searched for toward reddened stars where abundant C2 hadbeen reported and toward other stars with high color excess. Absorptionfrom C3 has been detected toward 15 stars with color excessE(B-V) from 0.33 to 1.12. The observed C3 column densities,ranging from 1012 to 1013 cm-2, arewell correlated with the corresponding C2 column densities,with N(C2)/N(C3)~40, indicating their closechemical relation. The carbon-rich sight line toward HD 204827 (forwhich no previous C2 observation had been reported) has byfar the highest C3 and C2 column densities. Thechemistry of formation of C3 from C2 is discussed.A search for the next strongest 020-000 vibronic band was unsuccessfulas a result of the low Franck-Condon factor and interference with astellar line. Searches for C4 and C5 werenegative.
| Merged catalogue of reflection nebulae
Several catalogues of reflection nebulae are merged to create a uniformcatalogue of 913 objects. It contains revised coordinates,cross-identifications of nebulae and stars, as well as identificationswith IRAS point sources.The catalogue is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/399/141
| A Critical Examination of the l-C3H-2 Spectrum and the Diffuse Interstellar Bands
It has recently been suggested by J. P. Maier's group that the originband and three vibronic bands of the linear propadienylidene anionl-C3H-2 match the diffuse interstellarbands (DIBs). We have examined the wavelength ranges in question usingdata from our ongoing DIB survey at the Apache Point Observatory. Wefind that the strongest DIB (λ6993) is not an acceptablewavelength match to the origin band ofl-C3H-2, based on high-resolutionlaboratory data. The nondetection of interstellar features correspondingto the K=2<--1 and K=0<--1 branches of paral-C3H-2 also argues against theassignment of λ6993 to the K=1<--0 branch of orthol-C3H-2. Two of the three DIBs thathave been attributed to vibronic bands do not correlate in intensitywith λ6993, providing further evidence against the assignment ofthis set of DIBs to l-C3H-2.
| Observations of H3 in the Diffuse Interstellar Medium
Surprisingly large column densities of H+3 havebeen detected using infrared absorption spectroscopy in seven diffusecloud sight lines (Cygnus OB2 12, Cygnus OB2 5, HD 183143, HD 20041, WR104, WR 118, and WR 121), demonstrating that H+3is ubiquitous in the diffuse interstellar medium. Using the standardmodel of diffuse cloud chemistry, our H+3 columndensities imply unreasonably long path lengths (~1 kpc) and lowdensities (~3 cm-3). Complimentary millimeter-wave, infrared,and visible observations of related species suggest that the chemicalmodel is incorrect and that the number density ofH+3 must be increased by 1-2 orders of magnitude.Possible solutions include a reduced electron fraction, an enhanced rateof H2 ionization, and/or a smaller value of theH+3 dissociative recombination rate constant thanimplied by laboratory experiments.
| Polarimetric Studies of Stars with an Infrared Emission Excess
The results of polarimetric and IR (IRAS) observations of 24 B-A-F starsare given. Intrinsic polarization of the light from 11 of the 24 starsis observed. The degree of polarization for the other 13 stars is withinthe measurement errors. Two-color diagrams are also constructed. From acomparison of the degree of polarization with the color index on thetwo-color diagrams it is seen that 8 of these 13 stars probably are ofthe Vega type, while 5 are stars with gasdust shells and/ordiskshells. It is shown that 6 of the aforementioned 11 starswith intrinsic polarization evidently are stars with gasdustshells and/or diskshells, while 5 of them (also including No. 24)are of the Vega type. It is also shown that the IR emission from 10 ofthe stars corresponds to a power-law distribution F . This fact may beexplained both by freefree transitions of electrons and bythermal emission from dust grains in circumstellar gasdust shells(disks).
| Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i
This work is the second part of the set of measurements of v sin i forA-type stars, begun by Royer et al. (\cite{Ror_02a}). Spectra of 249 B8to F2-type stars brighter than V=7 have been collected at Observatoirede Haute-Provence (OHP). Fourier transforms of several line profiles inthe range 4200-4600 Å are used to derive v sin i from thefrequency of the first zero. Statistical analysis of the sampleindicates that measurement error mainly depends on v sin i and thisrelative error of the rotational velocity is found to be about 5% onaverage. The systematic shift with respect to standard values fromSlettebak et al. (\cite{Slk_75}), previously found in the first paper,is here confirmed. Comparisons with data from the literature agree withour findings: v sin i values from Slettebak et al. are underestimatedand the relation between both scales follows a linear law ensuremath vsin inew = 1.03 v sin iold+7.7. Finally, thesedata are combined with those from the previous paper (Royer et al.\cite{Ror_02a}), together with the catalogue of Abt & Morrell(\cite{AbtMol95}). The resulting sample includes some 2150 stars withhomogenized rotational velocities. Based on observations made atObservatoire de Haute Provence (CNRS), France. Tables \ref{results} and\ref{merging} are only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/897
| Rejection of the C-7 Diffuse Interstellar Band Hypothesis
Using the new high-resolution (~8 km s-1) echellespectrograph on the 3.5 m telescope at the Apache Point Observatory, wehave begun a high-sensitivity survey of the diffuse interstellar bands(DIBs) in a large sample of reddened stars. Now that we are 2 years intothis long-term survey, our sample includes over 20 reddened stars thatshow at least one of the DIBs that had been suggested to be caused byC-7, based on the gas-phase measurement of theC-7 spectrum by J. P. Maier's group. Thehigh-quality astronomical data from this larger sample of stars, alongwith the spectroscopic constants from the new laboratory work recentlyreported by Maier's group, have enabled us to examine more carefully theagreement between C-7 and the DIBs. We find thatnone of the C-7 bands match the DIBs in wavelengthor expected profile. One of the DIBs (λ5748) attributed toC-7 is actually a stellar line. The two strongestDIBs attributed to C-7 (λ6270 andλ4964) are not correlated in strength, so they cannot share thesame carrier. On the whole, we find no evidence supporting thehypothesis that C-7 is a carrier of the DIBs.
| GasDust Shells around Some Early-Type Stars with an IR Excess (of Emission)
The results of an investigation of IR (IRAS) observations of 58OBAF stars of different luminosity classes, whichare mainly members of various associations, are presented. The colorindices of these stars are determined and two-color diagrams areconstructed. The emission excesses at 12 and 25 mm (E 12 and E 25) arealso compared with the absorption A1640 of UV radiation. It is concludedthat 24 stars (of the 58 investigated) are disk systems of the Vegatype, to which Vega = N 53 also belongs. Eight known stars of the Vegatype are also given in the figures for comparison. The remaining 34stars may have gasdust shells and/or shelldisks. The IRemission excesses of the 34 investigated stars and 11 comparison stars(eight of them are Be-Ae stars) are evidently due both to thermalemission from grains and to the emission from freefreetransitions of electrons in the gasdust shells of these stars.
| The Stars in Camelopardalis OB1: Their Distance and Evolutionary History
An investigation is undertaken of the optically identified Population Iobjects in the Cam OB1 region. From the analysis of these objects it isdetermined that the distance to the Cam OB1 stars is 975+/-90 pc. Atheoretical H-R diagram for the Cam OB1 stars reveals that starformation has been going on in the region for1×106-1×108 yr. At present, the mostactive site of star formation is Cam R1, which shows an asymmetry in thedistribution of optically identified Population I objects. The majorityof the pre-main-sequence stars lie in the northern half of theassociation, while the main-sequence stars and evolved stars lie in thesouthern half.
| A possible sets of diffuse bands originating at the same carrier
This paper discusses measurements of eight selected diffuse interstellarbands (DIBs): lambda lambda 5793, 5809, 5819, 5828, 6196, 6397, 6614 and6660 performed in high resolution, high S/N spectra of 41 reddenedstars. Central depths, considered less error-prone than equivalentwidths, are measured and mutual correlations between the selected DIBsare analyzed. Tight correlations between the DIBs: 5809, 6196, 6614 and6660 may suggest their common origin despite their widths differing by afactor of up to 2. The performed simulations prove that this fact doesnot preclude a common, molecular carrier of such features.
| A Mid-infrared Imaging Survey of Proto-Planetary Nebula Candidates
We present the data from a mid-infrared (MIR) imaging survey of 66proto-planetary nebula candidates using two MIR cameras (MIRAC2 andBerkcam) at the NASA Infrared Telescope Facility and the United KingdomInfrared Telescope. The goal of this survey is to determine the size,flux, and morphology of the MIR emission regions, which sample the innerregions of the circumstellar dust shells of proto-planetary nebulae. Weimaged these proto-planetary nebulae with narrowbandfilters(Deltalambda/lambda~10%) at wavelengths of notable dust features.With our typical angular resolution of 1", we resolve 17 sources, find48 objects unresolved, and do not detect one source. For several sourceswe checked optical and infrared associations and positions of thesources. In table format, we list the size and flux measurements for allof the detected objects and show figures of all of the resolved sources.The proto-planetary nebula candidate sample includes, in addition to thepredominant proto-planetary nebulae, extreme asymptotic giant branchstars, young planetary nebulae, a supergiant, and a luminous bluevariable. We find that dust shells that are cooler (T~150 K) andbrighter in the infrared are more easily resolved. Eleven of theseventeen resolved sources are extended and fall into one of two typesof MIR morphological classes: core/elliptical or toroidal.Core/elliptical structures show unresolved cores with lower surfacebrightness elliptical nebulae. Toroidal structures show limb-brightenedpeaks suggesting equatorial density enhancements. We argue thatcore/ellipticals have denser dust shells than toroidals.
| Empirical calibration of the lambda 4000 Å break
Empirical fitting functions, describing the behaviour of the lambda 4000Ä break, D4000, in terms of effective temperature,metallicity and surface gravity, are presented. For this purpose, thebreak has been measured in 392 stars from the Lick/IDS Library. We havefollowed a very detailed error treatment in the reduction and fittingprocedures, allowing for a reliable estimation of the breakuncertainties. This calibration can be easily incorporated into stellarpopulation models to provide accurate predictions of the break amplitudefor, relatively old, composite systems. Table 1 is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
| Understanding A-type supergiants. I. Ultraviolet and visible spectral atlas
This paper is the first of a series whose aim is to perform a systematicstudy of A-type supergiant atmospheres and winds. Here we present aspectral atlas of 41 A-supergiants observed by us in high and mediumresolution in the visible and ultraviolet. The atlas consists ofprofiles of the Hα , Hβ , Hγ , Hdelta , Hepsilon , CaII (H and K), Na I (D1 and D2), Mg II4481, Mg II [uv1] and FeII [uv1, uv2, uv3, uv62, uv63, uv161] lines for 41 stars with spectraltypes ranging from B9 to A9 and luminosity classes Ia, Iab and Ib, andprovides the basic data for a thoughtful study of these stars. Theoverall characteristics of the sample as well as the data reductionprocedures are described. We also present some examples of spectralvariability. Figures 1-3 are only available in electronic form at thehttp://www.edpsciences.com} of A-type supergiants\fnmsep\thanks{Based onobservations made with the INT and JKT telescopes operated on the islandof La Palma by the RGO in the Spanish Observatorio del Roque de LosMuchachos of the Instituto de Astrofisica de Canarias, with the 2.2~mtelescope at Calar Alto Observatory, Spain, with the Bernard Lyot 2~mtelescope at Pic Du Midi Observatory, France and observations collectedat the European Southern Observatory at La Silla, Chile.
| On correlations between diffuse interstellar bands
One way to better apprehend the problem of diffuse interstellar bands(DIBs) is to search for correlations between the bands in a large sampleof spectra towards various lines of sight: a strict correlation mayimply that a common carrier is at the origin of the bands, whereas anon-correlation means that different species are involved. We proposethis observational test for 10 DIBs collected in up to 62 Galactic linesof sight. Strong DIBs do not strictly correlate, and sometimes thecorrelation is very poor. Only one example of a strict correlation hasbeen found in our sample between the DIBs at 6614 and 6196 Ä, thatcould signify a single carrier for those two bands. The general absenceof strict correlations is discussed in the context of molecular carriersfor the DIBs.
| Suprathermal rotation of PAHs in the ISM II. Observational evidence for the rotational broadening of lambda 5797 DIB in reflection nebulae - implication for the carrier size
In a previous paper, we described a model which can explain thelambda5797 diffuse interstellar band (DIB) profile as seen in absorptionin the diffuse interstellar medium and in emission in the Red Rectangle(RR), as a rotational envelope of electronic transitions where themolecular carrier is a free PAH of size ~ 40 atoms. One of the strongestpredictions is the behaviour of the rotational temperature of PAH in thecase of regions rich in UV such as Reflection Nebulae: it must besuprathermal with respect to the gas temperature but clamped to ~ 100 Kfor any PAH size. The width of the DIB, in such regions, can then bebroader than in the classical ISM (T_rot ~ 30 K) if the values of themolecular transition are favorable. In order to test this prediction, wehave obtained high resolution spectra of 27 reddened early type stars,mostly in reflection nebulae, in order to compare their lambda 5797 DIBwidth to those of stars in classical diffuse interstellar medium. Thesespectra were made for several DIBs such as lambda 5797, lambda6379 andlambda6613 , with a spectral resolving power of about 60 000. Theanalysis of the results agrees with our predic tion since the width ofthe lambda 5797 DIB is broader in a majority of areas with strong UVradiation. Moreover, the broadening is not observed on DIBs lambda6379and lambda6613 , indicating that the molecular parameters of theelectronic transitions at the origin of the different DIBs are prettyvariable from one DIB to another and confirming that the measuredbroadening on lambda 5797 is not due to an instrumental bias. Thestatistical measurement of the lambda 5797 width in this medium permitsthe derivation of new constraints on the size of the carrier of thisDIB, a molecule that should have 30 to 45 carbon atoms if, as wepropose, it is indeed a PAH. Based on observations made at Observatoirede Haute Provence (CNRS), France.
| Understanding A-type supergiants. II. Atmospheric parameters and rotational velocities of Galactic A-type supergiants
We present the second paper of a series whose aim is to perform a globalstudy of Galactic A-supergiants. Very little work has been carried outto determine the stellar parameters of these stars. This is illustratedwith a brief review of some previous works. In this paper we analyze thedetermination of absolute magnitudes, spectral types and atmosphericparameters using the most recent Kurucz LTE blanketed model atmospheresand we discuss the applicability of the calibrations, such as theSchmidt-Kaler's (\cite{Sch-K}) calibration. Rotation is also animportant parameter in A-supergiants but their rotational velocities arepoorly known. We have calculated projected rotational velocities fromthe Fourier analysis of the observed Mg II (4481 Ä) line. Based onobservations made with the INT and JKT telescopes operated on the islandof La Palma by the RGO in the Spanish Observatorio del Roque de LosMuchachos of the Instituto de Astrofisica de Canarias, with the 2.2mtelescope at Calar Alto Observatory, Spain, with the Bernard Lyot 2mtelescope at Pic Du Midi Observatory, France and observations collectedat the European Southern Observatory at La Silla, Chile
| UBV beta Database for Case-Hamburg Northern and Southern Luminous Stars
A database of photoelectric UBV beta photometry for stars listed in theCase-Hamburg northern and southern Milky Way luminous stars surveys hasbeen compiled from the original research literature. Consisting of over16,000 observations of some 7300 stars from over 500 sources, thisdatabase constitutes the most complete compilation of such photometryavailable for intrinsically luminous stars around the Galactic plane.Over 5000 stars listed in the Case-Hamburg surveys still lackfundamental photometric data.
| Temperatures for A0-K0 Supergiants from 13-Color Photometry
Observations on the 13-color photometric system are reported for 71A0-K0 supergiant stars brighter than V=6.0. Three independent methods todetermine the effective temperatures for A0-K0 supergiants from their13C photometry are discussed: 1) Calibrations between T$eff$and reddening-free indices are developed; temperatures were collectedfrom the literature for the calibration stars, and most of them werespectroscopically determined. 2) An empirical correlation betweenintrinsic colors in the 13C system and T$eff$ has beenderived. 3) The unreddened colors are compared with synthetic colorscalculated by Kurucz (1989); this leads to simultaneous estimates forT$eff$ and log $g$. The estimated uncertainties inT$eff$ by the three methods are comparable and areapproximately plus or minus 200-300K. (SECTION: Stars)
| On the Variability of Early A-Type Supergiants
An examination of the Hipparcos photometry of 26 bright early A-typesupergiants shows that they are all variable.
| H gamma and H delta Absorption Features in Stars and Stellar Populations
The H gamma and H delta absorption features are measured in a sample of455 (out of an original 460) Lick/IDS stars with pseudo--equivalentwidth indices. For each Balmer feature, two definitions, involving anarrow (~20 Angstroms) and a wide (~40 Angstroms) central bandpass, aremeasured. These four new Balmer indices augment 21 indices previouslydetermined by Worthey et al., and polynomial fitting functions that giveindex strengths as a function of stellar temperature, gravity, and[Fe/H] are provided. The new indices are folded into models for theintegrated light of stellar populations, and predictions are given forsingle-burst stellar populations of a variety of ages and metallicities.Contrary to our initial hopes, the indices cannot break a degeneracybetween burst age and burst strength in post-starburst objects, but theyare successful mean-age indicators when used with sensitive metallicityindicators. An appendix gives data, advice, and examples of how totransform new spectra to the 25-index Lick/IDS system.
| A Survey of Near-Infrared Emission in Visual Reflection Nebulae
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..102..369S&db_key=AST
| Search for fullerenes and PAHs in the diffuse interstellar medium
Not Available
| The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJS...99..135A&db_key=AST
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Персеј |
| Ректацензија: | 03h15m48.00s |
| Deклинација: | +57°08'27.0" |
| Apparent магнитуда: | 5.79 |
| Даљина: | 495.05 parsecs |
| Proper motion RA: | -2 |
| Proper motion Dec: | -1.3 |
| B-T magnitude: | 6.574 |
| V-T magnitude: | 5.885 |
Каталог и designations:
|
INHABITED SKY
