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AKARI's infrared view on nearby stars. Using AKARI infrared camera all-sky survey, 2MASS, and Hipparcos catalogs
Context. The AKARI, a Japanese infrared space mission, has performed anAll-Sky Survey in six infrared-bands from 9 to 180 ?m with higherspatial resolutions and better sensitivities than IRAS. Aims: Weinvestigate the mid-infrared (9 and 18 ?m) point source catalog (PSC)obtained with the infrared camera (IRC) onboard AKARI, in order tounderstand the infrared nature of the known objects and to identifypreviously unknown objects. Methods: Color-color diagramsand a color-magnitude diagram were plotted with the AKARI-IRC PSCand other available all-sky survey catalogs. We combined the Hipparcosastrometric catalog and the 2MASS all-sky survey catalog with theAKARI-IRC PSC. We furthermore searched literature and SIMBADastronomical database for object types, spectral types, and luminosityclasses. We identified the locations of representative stars and objectson the color-magnitude and color-color diagram schemes. Theproperties of unclassified sources can be inferred from their locationson these diagrams. Results: We found that the (B-V) vs.(V-S9W) color-color diagram is useful for identifying thestars with infrared excess emerged from circumstellar envelopes ordisks. Be stars with infrared excess are separated well from other typesof stars in this diagram. Whereas (J-L18W) vs. (S9W-L18W)diagram is a powerful tool for classifying several object types.Carbon-rich asymptotic giant branch (AGB) stars and OH/IR stars formdistinct sequences in this color-color diagram. Young stellarobjects (YSOs), pre-main sequence (PMS) stars, post-AGB stars, andplanetary nebulae (PNe) have the largest mid-infrared color excess andcan be identified in the infrared catalog. Finally, we plot the L18W vs.(S9W-L18W) color-magnitude diagram, using the AKARI data togetherwith Hipparcos parallaxes. This diagram can be used to identify low-massYSOs and AGB stars. We found that this diagram is comparable to the [24]vs. ([8.0]-[24]) diagram of Large Magellanic Cloud sources usingthe Spitzer Space Telescope data. Our understanding of Galactic objectswill be used to interpret color-magnitude diagram of stellar populationsin the nearby galaxies that Spitzer Space Telescope observed. Conclusions: Our study of the AKARI color-color andcolor-magnitude diagrams will be used to explore properties ofunknown objects in the future. In addition, our analysis highlights afuture key project to understand stellar evolution with a circumstellarenvelope, once the forthcoming astronometrical data with GAIA areavailable.Catalog (full Tables 3 and 4) are only available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/514/A2
| CH stars at high Galactic latitudes
Carbon-rich stars of Population II, such as CH stars, can provide directinformation on the role of low- to intermediate-mass stars of the haloin early Galactic evolution. Thus accurate knowledge of the CH stellarpopulation is a critical requirement for building up scenarios for earlyGalactic chemical evolution. In the present work, we report on severalCH stars identified in a sample of faint high-latitude carbon stars fromthe Hamburg survey and discuss their medium-resolution spectra coveringthe wavelength range 4000-6800 Å. Estimation of the depths of the(1,0)12C12C λ4737 and(1,0)12C13C λ4744 bands in these starsindicates an isotopic ratio 12C/13C ~ 3, apartfrom a few exceptions; these ratios are consistent with existingtheories of CH stellar evolution. The stars of the Hamburg survey, atotal of 403 objects, were reported to be carbon star candidates withstrong C2 and CN molecular bands. In the first phase ofobservation, we acquired spectra of 91 objects. Inspection of thespectra of those objects shows 51 objects with C2 molecularbands in their spectra, of which 13 stars have low flux below about 4300Å. There are 25 objects that show weak or moderate CH and CNbands, 12 objects that show weak but detectable CH bands, and threeobjects that do not show any molecular bands due to C2, CN orCH in their spectra. Objects with C2 molecular bands and withgood signals bluewards of 4300 Åthat show prominent CH bands intheir spectra are potential candidate CH stars. There were 35 suchcandidates found in the present sample of 91 objects observed so far.The set of CH stars identified could be the targets of subsequentobservation at high resolution for a detailed and comprehensive analysisto understand their role in early Galactic chemical evolution.
| New periodic variables from the Hipparcos epoch photometry
Two selection statistics are used to extract new candidate periodicvariables from the epoch photometry of the Hipparcos catalogue. Theprimary selection criterion is a signal-to-noise ratio. The dependenceof this statistic on the number of observations is calibrated usingabout 30000 randomly permuted Hipparcos data sets. A significance levelof 0.1 per cent is used to extract a first batch of candidate variables.The second criterion requires that the optimal frequency be unaffectedif the data are de-trended by low-order polynomials. We find 2675 newcandidate periodic variables, of which the majority (2082) are from theHipparcos`unsolved' variables. Potential problems with theinterpretation of the data (e.g. aliasing) are discussed.
| The stellar content of the Hamburg/ESO survey II. A large, homogeneously-selected sample of high latitude carbon stars
We present a sample of 403 faint high latitude carbon (FHLC) starsselected from the digitized objective prism plates of the Hamburg/ESOSurvey (HES). Because of the ~ 15 Å spectral resolution and highsignal-to-noise ratio of the HES prism spectra, our automated procedurebased on the detection of C2 and CN molecular bands permitshigh-confidence identification of carbon stars without the need forfollow-up spectroscopy. From a set of 329 plates (87 % of the survey),covering 6 400 deg2 to a magnitude limit of V ~ 16.5, weanalyze the selection efficiency and effective surface area of the HESFHLC survey to date. The surface density of FHLC stars that we detect(0.072+/- 0.005 deg-2) is 2-4 times higher than that ofprevious objective prism and CCD surveys at high galactic latitude, eventhough those surveys claimed a limiting magnitude up to 1.5 magnitudesfainter. This attests to the highest selection sensitivity yet achievedfor these types of stars. Based on observations collected at theEuropean Southern Observatory, Chile (Proposal IDs 145.B-0009 and63.L-0148). Table A.1 is only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/375/366
| Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
| General Catalog of Galactic Carbon Stars by C. B. Stephenson. Third Edition
The catalog is an updated and revised version of Stephenson's Catalogueof Galactic Cool Carbon Stars (2nd edition). It includes 6891 entries.For each star the following information is given: equatorial (2000.0)and galactic coordinates, blue, visual and infrared magnitudes, spectralclassification, references, designations in the most significantcatalogs and coordinate precision classes. The main catalog issupplemented by remarks containing information for which there was noplace in entries of the main part, as well as some occasional notesabout the peculiarities of specific stars.
| First Byurakan Spectral Sky Survey. Stars of late spectral types. ‑11° ≤ δ ≤ ‑7° belt
A 10th list of late-type M and C stars found on plates of the FirstByurakan Spectral Sky Survey in the ‑ 11° ≤ δ ≤‑ 7° belt with an area of about 1070 deg2 is given.The list contains data on 169 red stars, 117 of which were found for thefirst time: 8 are new C stars, 3 are Cstar candidates, 104 are M stars,1 is either an M or an S star, and 1 object on the survey plate cannotbe classified. Of the 117 objects, 47 are unidentified IRAS sources. Astatistical analysis of the objects that are and are not identified withIRAS sources shows that the identified stars are, with a highprobability, brighter and have relatively more massive envelopes. Twostars were found to have fairly large brightness variability (with anamplitude of at least 6m.O). Gasdust shells are assumed toexist around nine of the IRAS sources. The equatorial coordinates,spectral types, and stellar magnitudes, determined on Palomar E maps,are given for the selected objects.
| A New Version of the Catalog of CH and Related Stars (CH95 Catalog)
A new version of the catalog of CH and related stars contains 244 fieldstars and 17 globular cluster stars. Here a list of these stars withtheir coordinates, their positions in the HR diagram and somestatistical diagrams is presented. The catalog will soon be available inthe printed and computerized versions.
| Catalogue of CH and metal-deficient barium stars
Not Available
| A general catalogue of cool carbon stars
Not Available
| CH stars as galaxy halo tracers
A spectroscopic survey of high-latitude carbon stars shows that many ofthese stars are CH stars with characteristically high space velocities.Some newly determined CH stars and others compiled from the literatureare employed to determine the local space density and kinematics ofthese stars. For the local space density, the surprisingly high value ofrho = 5.6 x 10 to the -9th/cu pc is obtained for M(V) ranging from -0.25to -2.2. The main result of the present study is that the velocitydispersion perpendicular to the galactic plane sigma(W) is alwaysgreater than approximately 114 km/s, irrespective of how the sample ofknown CH stars and CH star candidates is subdivided.
| CH-like stars
The properties of CH-like stars are discussed on the basis ofYamashita's (1972) classification of some 290 carbon stars. The CH-likestars are shown to be early-type red carbon stars. Their spectra arefound to be very similar to those of CH stars (typical high-velocityPopulation II carbon stars), but their proper motions and radialvelocities reveal no evidence of high velocity. The spectra are alsofound to be similar to those of Ba II stars with enhanced carbonfeatures. Abundance anomalies in the spectra of various types of oldpeculiar stars are briefly discussed. It is noted that 16 CH-like starshave been discovered thus far.
| Radial Velocities of Nineteen Carbon Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974PASJ...26..159Y&db_key=AST
| A general catalogue of cool carbon stars
Not Available
| New Peculiar Spectra
Not Available
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Группы:
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Наблюдательные данные и астрометрия
| Созвездие: | Чаша |
| Прямое восхождение: | 11h07m19.41s |
| Склонение: | -10°13'15.8" |
| Видимая звёздная величина: | 10.768 |
| Собственное движение RA: | -4.6 |
| Собственное движение Dec: | -11.9 |
| B-T magnitude: | 12.541 |
| V-T magnitude: | 10.915 |
Каталоги и обозначения:
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