Stellar Spectrophotometry Research Articles

Variable stars within 25 arcmin of the LMC globular cluster NGC 2210

view Abstract Citations (26) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Variable Stars Within 25 Arcmin of the LMC Globular Cluster NGC 2210 Hazen, Martha L. ; Nemec, James M. Abstract Based on a photometric analysis of 63 photographic plates taken between 1975 and 1985 with the CTIO 1.5 and 4 m telescopes, and new photoelectric and CCD photometry, pulsational characteristics are presented for 52 newly discovered field RR Lyrae variables within 0.5^deg^ of the LMC globular cluster NGC 2210. The surface density of the field RR Lyrae stars is 80 per square degree, which is as high as that found in Graham's NGC 1783 field, and higher than that found in several outer halo fields of the LMC. Eleven RR Lyrae stars located within the tidal radius of the cluster, and 33 non-RR Lyrae field variables are also discussed. The mean periods of the 40 ab-type and 12 c-type field RR Lyrae stars, <P_ab_> = 0.576+/-0.057 day and <P_c_> = 0.345+/-0.049 day, fall between the values for the two Oosterhoff groups in our Galaxy. Since such mean periods are also found in the NGC 1783 and NGC 2257 regions of the LMC, we conclude that such an intermediate Oosterhoff type is a general characteristic of LMC field RR Lyrae stars. Based on a comparison of the observed period-amplitude (P-A) relation with those for the RR Lyrae stars in the galactic globular clusters M3 and M15, the mean metallicity of the NGC 2210 field RR Lyrae stars appears to be [Fe/H]= - 1.8. Support for this conclusion comes also from the observed ratio of RRab to RRc stars. The mean <B> for the field variables, 19.56+/-0.02 mag, when taken with an assumed distance to the LMC of 50+/-3 kpc, and a line-of-sight reddening E(B-V) = 0.08+/-0.01, suggests that the absolute magnitude of the field RR Lyrae stars is M_B_= 0.75+/-0.20 mag. Publication: The Astronomical Journal Pub Date: July 1992 DOI: 10.1086/116224 Bibcode: 1992AJ....104..111H Keywords: Astronomical Photography; Charge Coupled Devices; Globular Clusters; Magellanic Clouds; Variable Stars; Cepheid Variables; Light Curve; Star Clusters; Stellar Oscillations; Stellar Spectrophotometry; Astrophysics; STARS: VARIABLES: RR LYRAE; GLOBULAR CLUSTERS: INDIVIDUAL: NGC 2210 full text sources ADS | data products SIMBAD (192) NED (1)

Broadband UBVRI photometry of the Baldwin-Stone Southern Hemisphere spectrophotometric standards

view Abstract Citations (289) References (7) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Broadband UBVRI Photometry of the Baldwin-Stone Southern Hemisphere Spectrophotometric Standards Landolt, Arlo U. Abstract The paper presents photometric broadband UBVRI data of Baldwin-Stone Southern Hemisphere spectrophotometric standard stars, including results of error analysis. The sensitivity functions of the photomultipliers are also illustrated and tabulated. Publication: The Astronomical Journal Pub Date: July 1992 DOI: 10.1086/116243 Bibcode: 1992AJ....104..372L Keywords: Broadband; Color-Magnitude Diagram; Southern Hemisphere; Stellar Luminosity; Stellar Spectrophotometry; Ubv Spectra; Astronomical Observatories; Data Bases; Standards; Stellar Magnitude; Telescopes; Astronomy; STARS: FUNDAMENTAL PARAMETERS; CATALOGS full text sources ADS | data products SIMBAD (19) GCPD (1)

Washington photometry of nearby F, G, and K dwarfs

view Abstract Citations (12) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Washington Photometry of Nearby F, G, and K Dwarfs Gonzalez, Guillermo ; Piche, Francois Abstract Washington C, M, T1, T2, and Johnson V, B-V photometry of nearby F, G, and K dwarfs are presented. The present calibrations of (Fe/H) with the Washington colors have residuals approaching those of spectroscopic metallicities. The color-magnitude calibrations are based on nearby stars having precise parallaxes with metallicities ranging from 0.25 to -1.8 dex relative to the sun. It is concluded that the C-M and M - T2 colors are the best ones for determining metallicities in dwarfs using the Washington photometric system; the T1 filter would be redundant to the M filter. The study is a preliminary one and slight refinements from additional observations would allow these calibrations to replace the Hyades as the lowest rung in the distance ladder. Publication: The Astronomical Journal Pub Date: June 1992 DOI: 10.1086/116209 Bibcode: 1992AJ....103.2048G Keywords: Dwarf Stars; F Stars; G Stars; K Stars; Star Clusters; Ubv Spectra; Astronomical Catalogs; Color-Magnitude Diagram; Metallicity; Stellar Luminosity; Stellar Spectrophotometry; Astrophysics; SUBDWARFS; STARS: ABUNDANCES; TECHNIQUES: PHOTOMETRIC full text sources ADS | data products GCPD (1)

A search for stars of very low metal abundance. II

view Abstract Citations (522) References (54) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Search for Stars of Very Low Metal Abundance. II Beers, Timothy C. ; Preston, George W. ; Shectman, Stephen A. Abstract Spectroscopic observations for 1044 stars located primarily in the southern Galactic hemisphere are reported; the stars were chosen from a list of candidate metal-deficient stars discovered in the HK objective-prism survey. Radial velocities and line indices based on the equivalent widths of Ca II, K, H-gamma and H-delta, and the CH G band are reported. Estimates of metallicity for 874 stars with derived abundances less than -0.5 are presented. The number of extremely metal-poor stars (Fe/H is not greater than -2.0) reported in the present sample is roughly quadruple the same size of nonkinematically selected stars of similar metal abundance reported in previous work, and is on the order of the total previous samples of stars in this abundance regime when all sources are included. The number of stars with Fe/H not greater than -3.0 in the present sample is seven times the number of previously identified stars with spectroscopically determined abundances which are this low. Publication: The Astronomical Journal Pub Date: June 1992 DOI: 10.1086/116207 Bibcode: 1992AJ....103.1987B Keywords: Metallicity; Stellar Composition; Stellar Spectrophotometry; Abundance; Color-Color Diagram; Spectral Line Width; Star Formation; Stellar Magnitude; Ubv Spectra; Astrophysics; STARS: ABUNDANCES full text sources ADS | data products SIMBAD (1024) GCPD (1) CDS (1) Related Materials (5) Part 1: 1985AJ.....90.2089B Part 3: 1999ApJS..123..639N Part 4: 2000AJ....119.2882A Part 5: 2000AJ....120.2065B Part 6: 2014AJ....147..136R

A globular cluster system around the supergiant elliptical NGC 3842

view Abstract Citations (18) References (41) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Globular Cluster System Around the Supergiant Elliptical NGC 3842 Butterworth, Steven T. ; Harris, William E. Abstract NGC 3842 is a dominantly large and structurally normal supergiant elliptical galaxy within the Virgo-like cluster Abell 367. We have carried out deep B-magnitude CCD imaging in the envelope of this galaxy in a search for its globular cluster system. Our photometry shows a significant population of clusters beginning to appear for B > 24.5 and continuing to rise in numbers to the faint limit of our data at B ~26.0. The estimated total cluster population (specific frequency) is S_N_~=7-8,i.e., near the normal for Virgo-like giant ellipticals and almost a factor of two less populous than the prototypical "high-S_N_" cluster system around M87. These results suggest that galaxy size (luminosity) or morphology are not enough by themselves to produce a high-S_N_ globular cluster system. In addition, because NGC 3842 is not situated at the dynamical center of A1367, our results are consistent with the idea that central location within a rich environment is the most important single factor causing high-S_N_ systems to form. Publication: The Astronomical Journal Pub Date: June 1992 DOI: 10.1086/116198 Bibcode: 1992AJ....103.1828B Keywords: Elliptical Galaxies; Galactic Structure; Globular Clusters; Star Distribution; Stellar Luminosity; Stellar Spectrophotometry; Astrophysics; GALAXIES: ELLIPTICAL AND LENTICULAR; GLOBULAR CLUSTERS: GENERAL; GALAXIES: STAR CLUSTERS full text sources ADS | data products SIMBAD (11) NED (3)

The lithium abundances of the Capella giants

view Abstract Citations (22) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Lithium Abundances of the Capella Giants Pilachowski, Catherine A. ; Sowell, James R. Abstract The abundance of lithium in each of the two giants which comprise the spectroscopic binary star Capella has been redetermined using digital, electronic spectra and modern analytical techniques. The abundance of lithium in the warm (G0) secondary star is log Li = 3.0, consistent with the value seen in young, unevolved stars and the interstellar medium. The abundance of lithium in the cooler (G8) primary star is log Li = 0.8, similar to what is found in other red giants of similar spectral type. The lithium abundance in the primary star is less than would be expected from classical predictions. Possible explanations for the low lithium abundance are considered. The lithium abundance in the primary and its similarity to the Hyades giants support the conclusion that the primary is a 'clump' giant. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116183 Bibcode: 1992AJ....103.1668P Keywords: Binary Stars; G Stars; Giant Stars; Lithium; Metallicity; Abundance; Spectral Line Width; Stellar Evolution; Stellar Spectrophotometry; Astrophysics; BINARIES: SPECTROSCOPIC; STARS: GIANTS; STARS: ABUNDANCES full text sources ADS | data products SIMBAD (1)

Candidates for extreme carbon stars

view Abstract Citations (81) References (45) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Candidates for Extreme Carbon Stars Volk, Kevin ; Kwok, Sun ; Langill, Philip P. Abstract A group of candidates for extreme carbon stars has been identified based on their IRAS low-resolution spectra being similar to those of AFGL 3068 and IRC +10 deg 216, which are prototypes of highly evolved carbon stars with very high mass-loss rates. Ground-based photometry has been obtained for five of these sources in order to determine the peaks of their energy distributions. All five sources have color temperatures between 300 and 500 K, and have energy distributions very similar to AFGL 3068. The observed data are fitted with radiative transfer models with optical depths at 11.3 microns ranging from 1.4 to 8. These results suggest that these stars have among the most optically thick circumstellar envelopes of all carbon stars observed to date. Publication: The Astrophysical Journal Pub Date: May 1992 DOI: 10.1086/171344 Bibcode: 1992ApJ...391..285V Keywords: Asymptotic Giant Branch Stars; Carbon Stars; Stellar Envelopes; Stellar Evolution; Color-Color Diagram; Infrared Astronomy Satellite; Spectral Energy Distribution; Spectral Resolution; Stellar Spectra; Stellar Spectrophotometry; Astrophysics; STARS: CIRCUMSTELLAR MATTER; INFRARED: STARS; STARS: CARBON full text sources ADS | data products SIMBAD (33)

Period change rates for 46 RR Lyrae stars in NGC 7006

view Abstract Citations (17) References (18) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Period Change Rates for 46 RR Lyrae Stars in NGC 7006 Wehlau, Amelia ; Nemec, James M. ; Hanlan, Patricia ; Rich, R. M. Abstract Period change rates are presented for 46 RR Lyrae stars in the globular cluster NGC 7006 based on previously published photometry of photographic plates taken in the 1930s and 1950s by Hubble and Sandage, and new photometry of 35 photographic plates taken in 1984 with the Palomar 60 in telescope. The mean period change rate for the 42 RRab stars is (beta) = -0.06 +/- 0.04 d/Myr and the median is -0.04, which, for the horizontal branch (HB) type of NGC 7006, is one standard error below the median value of beta predicted by the Yale evolutionary HB models. Statistically significant evidence for a radial gradient in the (beta) values (in the sense that the beta values are more negative in the outer region of the cluster than in the inner) is also presented and discussed. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116171 Bibcode: 1992AJ....103.1583W Keywords: Blue Stars; Giant Stars; Globular Clusters; Stellar Spectrophotometry; Variable Stars; Astronomical Photography; Charge Coupled Devices; Light Curve; Photographic Plates; Astrophysics; STARS: VARIABLES: RR LYRAE; STARS: OSCILLATIONS full text sources ADS | data products SIMBAD (3)

New proper motions in the globular cluster M92

view Abstract Citations (33) References (41) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS New Proper Motions in the Globular Cluster M92 Rees, Richard F., Jr. Abstract New photometry, proper motions, and membership probabilities have been obtained for 365 stars in the region of the globular cluster M92. The accuracies of the proper motions greatly surpass those of previous studies. Strong evidence of systematic problems in previous photographic photometry is presented. A preliminary astrometric distance of 8.3 +/- 1.6 kpc is found, consistent with other distance determinations. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116170 Bibcode: 1992AJ....103.1573R Keywords: Globular Clusters; Stellar Motions; Astrometry; Astronomical Photography; Color-Magnitude Diagram; Stellar Spectrophotometry; Astrophysics; GLOBULAR CLUSTERS: INDIVIDUAL: M92; ASTROMETRY full text sources ADS | data products SIMBAD (363)

A new approach to the Cepheid period-luminosity law - Delta Scuti stars as small Cepheids

view Abstract Citations (43) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A New Approach to the Cepheid Period-Luminosity Law: (Delta) Scuti Stars as Small Cepheids Fernie, J. D. Abstract It is argued that the apparent separation of Delta Scuti stars and classical Cepheids into two classes is due to a simple selection effect, and that Delta Sct stars and Cepheids are really a single class of variable star. The precision with which the P-L and other relations are known can be greatly improved by combining the two classes. Publication: The Astronomical Journal Pub Date: May 1992 DOI: 10.1086/116179 Bibcode: 1992AJ....103.1647F Keywords: Cepheid Variables; Dwarf Stars; Hertzsprung-Russell Diagram; Stellar Luminosity; Supergiant Stars; Stellar Oscillations; Stellar Spectrophotometry; Astrophysics; DELTA SCUTI; CEPHEIDS; STARS: OSCILLATIONS full text sources ADS | data products SIMBAD (10)

The luminosity of supernovae of Type Ia. I - Apparent magnitudes at maximum light

view Abstract Citations (47) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Luminosity of Supernovae of Type Ia. I. Apparent Magnitudes at Maximum Light van den Bergh, Sidney ; Pazder, John Abstract All published UBV and m_pg_ m_pv_ photometry is used to determine maximum magnitudes for 31 supernovae of Type Ia (SN Ia). The main results of this work are summarized in Table I, which lists maximum magnitudes, and an estimate of their precision, for all objects which have been designated SN Ia on the basis of their spectra, and for a few supernovae in elliptical galaxies which were assumed to be of Type Ia. Figure 4 shows a Hubble diagram for SN Ia, in which the B(max) values have been corrected for absorption. With our adopted intrinsic colors this figure indicates that supernovae of Type Ia in late-type galaxies are 1.1 +/- 0.4 mag brighter than those in early-type galaxies. This suggests that it may be still premature to conclude that all SN Ia are good standard candles. Publication: The Astrophysical Journal Pub Date: May 1992 DOI: 10.1086/171256 Bibcode: 1992ApJ...390...34V Keywords: Galaxies; Red Shift; Stellar Luminosity; Stellar Magnitude; Stellar Spectrophotometry; Supernovae; Astronomical Photometry; Distance; Hubble Diagram; Light Curve; Astrophysics; GALAXIES: DISTANCES AND REDSHIFTS; STARS: FUNDAMENTAL PARAMETERS; STARS: SUPERNOVAE: GENERAL full text sources ADS | data products NED (63) SIMBAD (35)

New calibrators for the Cepheid period-luminosity relation

view Abstract Citations (35) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS New Calibrators for the Cepheid Period-Luminosity Relation Evans, Nancy R. Abstract IUE spectra of six Cepheids have been used to determine their absolute magnitudes from the spectral types of their binary companions. The stars observed are U Aql, V659 Cen, Y Lac, S Nor, V350 Sgr, and V636 Sco. The absolute magnitude for V659 Cen is more uncertain than for the others because its reddening is poorly determined and the spectral type is hotter than those of the others. In addition, a reddening law with extra absorption in the 2200 A region is necessary, although this has a negligible effect on the absolute magnitude. For the other Cepheids, and also Eta Aql and W Sgr, the standard deviation from the Feast and Walker period-luminosity-color (PLC) relation is 0.37 mag, confirming the previously estimated internal uncertainty. The absolute magnitudes for S Nor from the binary companion and from cluster membership are very similar. The preliminary PLC zero point is less than 2 sigma (+0.21 mag) different from that of Feast and Walker. The same narrowing of the instability strip at low luminosities found by Fernie is seen. Publication: The Astrophysical Journal Pub Date: April 1992 DOI: 10.1086/171238 Bibcode: 1992ApJ...389..657E Keywords: Cepheid Variables; Stellar Luminosity; Stellar Magnitude; Stellar Oscillations; Ultraviolet Spectra; Binary Stars; Companion Stars; Hertzsprung-Russell Diagram; Iue; Stellar Spectrophotometry; Astrophysics; STARS: BINARIES: SPECTROSCOPIC; STARS: FUNDAMENTAL PARAMETERS; STARS: OSCILLATIONS; STARS: VARIABLES: CEPHEIDS; ULTRAVIOLET: STARS full text sources ADS | data products SIMBAD (10) MAST (1) INES (1)

CCD Stromgren studies in NGC 6397

view Abstract Citations (33) References (56) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS CCD Stromgren Studies in NGC 6397 Anthony-Twarog, Barbara J. ; Twarog, Bruce A. ; Suntzeff, Nicholas B. Abstract Six fields in NGC 6397 are studied with CCD photometry in the Stromgren y, b, and v systems to expand the number of sampled photometric binaries and study their characteristics. The fiducial sequences for the cluster are determined to assess the binary population, and the fiducial CMD is analyzed to constrain the cluster age and distance. The distribution of the m(1) (b - y) diagram yields potential members, and about 7 percent of the main-sequence members are characterized as composites. An apparent distance modulus of (m - M) = 12.1 is derived from the reddening and Fe/H values, and these values lead to an age of more than 18 x 10 exp 9 yr from the luminosity of the turnoff. The standard main-sequence relations developed by McClure et al. (1987) and Sarajedini and King (1987) are compared to the present values. NGC 6397 is concluded to be one of the oldest clusters in a globular sample with an age spread of 5-6 x 10 exp 9 yr and assumed to reside in the old tail of a broad globular cluster-age distribution. Publication: The Astronomical Journal Pub Date: April 1992 DOI: 10.1086/116140 Bibcode: 1992AJ....103.1264A Keywords: Globular Clusters; Main Sequence Stars; Stellar Composition; Stellar Spectrophotometry; Ubv Spectra; Binary Stars; Charge Coupled Devices; Color-Magnitude Diagram; Metallicity; Stellar Luminosity; Stellar Parallax; Astrophysics; GLOBUALR CLUSTERS: INDIVIDUAL: NGC 6397; TECHNIQUES: PHOTOMETRY full text sources ADS | data products SIMBAD (14)

The Juggler - A three-lobed near-infrared reflection nebula toward CRL 2136 = OH 17.6 + 0.2

view Abstract Citations (38) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Juggler: A Three-lobed Near-Infrared Reflection Nebula toward CRL 2136 = OH 17.6+0.2 Kastner, Joel H. ; Weintraub, David A. ; Aspin, C. Abstract Near-IR polarimetric images of a complex nebula toward CRL 2136 = OH 17.6 + 0.2, an optically obscured maser source, are presented. The 2.2-micron images reveal three main lobes oriented in a triangle, with peaks separated by 5-8 arcsec. Two of the lobes extend over 30 arcsec from the center of the nebula, and one possesses filimentary structure. On the basis of the high degree and patterns of linear polarization throughout the nebula, it is concluded that the extended flux is due to scattering-off dust grains. It is inferred from the distribution of polarized light that a central source illuminates paraboloid or conical cavities within a dust envelope that is otherwise opaque to near-IR photons. The detection of a narrow, intense (46 +/-5 Jy) 22-GHz H2 maser line is confirmed at 26.3 km/s, which appears to coincide with prior detections of CO, CH, and HCN near that velocity. A model is proposed for explaining the dependence of polarization on wavelength previously reported for large aperture observations of CRL 2136 and several other protostars. Publication: The Astrophysical Journal Pub Date: April 1992 DOI: 10.1086/171210 Bibcode: 1992ApJ...389..357K Keywords: Astronomical Polarimetry; Infrared Imagery; Infrared Sources (Astronomy); Interstellar Masers; Near Infrared Radiation; Reflection Nebulae; Star Formation; Linear Polarization; Protostars; Stellar Spectrophotometry; Astrophysics; INFRARED: INTERSTELLAR: CONTINUUM; ISM: INDIVIDUAL ALPHANUMERIC: CRL 2136; ISM: REFLECTION NEBULAE; ISM: STRUCTURE; STARS: FORMATION full text sources ADS | data products SIMBAD (47)

Properties of the massive X-ray binary 4U 1700 - 37 = HD 153919

view Abstract Citations (61) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Properties of the Massive X-Ray Binary 4U 1700-37 = HD 153919 Heap, S. R. ; Corcoran, M. F. Abstract The system parameters for the massive X-ray binary 4U 1700 - 37 are reexamined in the light of modern spectroscopic theory and new UV and X-ray data. The system is composed of HD 153919, an O6f star having a stronger wind, and an accreting neutron star. Revised parameters for the Of component are derived which are in accord with the parameters of single Of stars, which resolves the problem that 'the O star is undermassive by a factor of 2' formulated by Conti (1978). The ratio of the terminal velocity of the wind to the photospheric escape velocity agrees with those of O stars. The discrepancy between the values of the wind acceleration parameter, derived from X-ray and UV data, is resolved. The acceleration of the wind is similar to that of single OB star winds. It is suggested that the supernova explosion producing the neutron star in 4U 1700 - 37 occurred over a million years ago when HD 153919 was still on the main sequence. Publication: The Astrophysical Journal Pub Date: March 1992 DOI: 10.1086/171086 Bibcode: 1992ApJ...387..340H Keywords: Massive Stars; Neutron Stars; O Stars; X Ray Binaries; Light Curve; Stellar Evolution; Stellar Mass Accretion; Stellar Spectrophotometry; Stellar Winds; Astrophysics; STARS: BINARIES: ECLIPSING; STARS: EMISSION-LINE; BE; STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 153919; STARS: NEUTRON; ULTRAVIOLET: STARS; X-RAYS: STARS full text sources ADS | data products SIMBAD (2) MAST (1) INES (1)

Possible models for the type IA supernova 1990N

view Abstract Citations (86) References (46) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Possible Models for the Type IA Supernova 1990N Shigeyama, Toshikazu ; Nomoto, Ken'ichi ; Yamaoka, Hitoshi ; Thielemann, Friedrich-Karl Abstract Possible interpretations of new spectral and photometric features of Type Ia supernova 1990N with carbon deflagration/detonation models are presented. To explain the presence of Si and Ca at high expansion velocities in SN 1990N, we suggest four possible models, among which is a carbon detonation in a white dwarf with a mass ~1 M_sun_. The slow rise of the light curve of SN 1990N can be reproduced by both the deflagration and detonation models if the optical opacity is somewhat larger than that previously adopted. Implications for the Hubble constant are discussed. Publication: The Astrophysical Journal Pub Date: February 1992 DOI: 10.1086/186281 Bibcode: 1992ApJ...386L..13S Keywords: Nuclear Reactions; Red Shift; Stellar Models; Stellar Spectrophotometry; Supernovae; White Dwarf Stars; Calcium; Hubble Constant; Light Curve; Silicon; Stellar Mass; Astrophysics; GALAXIES: DISTANCES AND REDSHIFTS; NUCLEAR REACTIONS; NUCLEOSYNTHESIS; ABUNDANCES; STARS: INDIVIDUAL ALPHANUMERIC: SN 1990N; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1990N; STARS: WHITE DWARFS full text sources ADS | data products NED (3) SIMBAD (2)

Photometry and spectroscopy of the very close early type binary SV Centauri

view Abstract Citations (15) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Photometry and Spectroscopy of the Very Close Early Type Binary SV Centauri Rucinski, S. M. ; Baade, D. ; Lu, W. X. ; Udalski, A. Abstract New high-quality observations of this unusual early type contact binary are presented. BVRI photometry of SV Cen provides a precise moment of minimum in March 1990. From high-resolution profiles of the He I line at 492.1 nm a new, improved set of orbital parameters was derived. Intrinsic line profile variability was not detected in either component and both photometry and spectroscopy. Low-noise spectra of the region around He II 468.6 nm showed no feature at any orbital phase, thus not giving a clue on the location of the source of a far-UV flux excess previously inferred from IUE observations. Since, for technical reasons, simultaneous EUV spectrophotometry with the Voyager spacecraft was lost, the temperature of this possible ultrahot spot could not be further constrained. Publication: The Astronomical Journal Pub Date: February 1992 DOI: 10.1086/116084 Bibcode: 1992AJ....103..573R Keywords: B Stars; Binary Stars; Stellar Spectrophotometry; Ultraviolet Astronomy; Centaurus Constellation; Extreme Ultraviolet Radiation; Helium; Light Curve; Stellar Evolution; Stellar Orbits; Astrophysics; BINARIES: CLOSE; BINARIES: SPECTROSCOPIC full text sources ADS | data products SIMBAD (3)

A search for T Tauri stars based on the IRAS point source catalog.

view Abstract Citations (225) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Search for T Tauri Stars Based on the IRAS Point Source Catalog. I. Gregorio-Hetem, J. ; Lepine, J. R. D. ; Quast, G. R. ; Torres, C. A. O. ; de La Reza, R. Abstract The results of the first part of a survey for new T Tauri stars, with spectroscopic and photometric observations of about 100 stars, are presented. A list of candidates has been selected by means of the IRAS Point Source Catalog, based on appropriate far-infrared colors. Coude spectra of the selected objects in the 655-673 nm wavelength range, which includes H-alpha and the resonance Li I line, have been obtained. Thirty-three new T Tauri stars, and a number of other interesting objects, like early type premain-sequence stars and Li-rich K giants, have been detected. Several new isolated T Tauri were found, including Hen 1, which may be the T Tauri star with the highest galactic latitude known, if its nature is confirmed. Publication: The Astronomical Journal Pub Date: February 1992 DOI: 10.1086/116082 Bibcode: 1992AJ....103..549G Keywords: Point Sources; Pre-Main Sequence Stars; Sky Surveys (Astronomy); Spaceborne Astronomy; Stellar Spectra; T Tauri Stars; Astronomical Catalogs; Far Infrared Radiation; H Alpha Line; Infrared Astronomy Satellite; Stellar Spectrophotometry; Astrophysics; STARS: PRE-MAIN SEQUENCE full text sources ADS | data products SIMBAD (121)

Line shapes of rotating stars with application to Alpha Lyrae

view Abstract Citations (10) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Line Shapes of Rotating Stars with Application to Alpha Lyrae Elste, G. H. Abstract Profiles of weak and medium strong lines in the high-resolution spectrum of Vega can in principle be understood by the center-to-limb variation of their equivalent widths, predicted by a standard model atmosphere. Finer details may require a different model structure depending on the latitude of the rotating star, and perhaps differential rotation. Publication: The Astrophysical Journal Pub Date: January 1992 DOI: 10.1086/170871 Bibcode: 1992ApJ...384..284E Keywords: Line Spectra; Spectral Line Width; Stellar Rotation; Stellar Spectra; Stellar Spectrophotometry; Astrophysics; LINE: PROFILES; STARS: INDIVIDUAL CONSTELLATION NAME: ALPHA LYRAE; STARS: ROTATION full text sources ADS | data products SIMBAD (1)

IR photometry of the stars in Terzan 2

view Abstract Citations (14) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS IR Photometry of the Stars in Terzan 2 Christian, C. A. ; Friel, E. D. Abstract The giant branch of the globular cluster Terzan 2 has been studied using the Infrared Imaging Camera at the United Kingdom Infrared Telescope. An IR color-magnitude diagram of this object has been obtained to study this cluster relative to clusters with known metallicities and ages to determine independent estimates for the parameters relevant to Terzan 2. The Terzan clusters are important as they are among the most metal-rich members of the so-called disk component of the globular cluster system, but they are located in a direction very close to the galactic center; hence, observations are particularly difficult due to interstellar obscuration. Assuming that the cluster has Fe/H about -0.25 (Armandroff and Zinn, 1988), Terzan 2 is found to be at an intrinsic distance modulus of 15.0 +/-0.2 mag with a reddening E(B-V) = 1.25 +/-0.15. At the corresponding distance, 10 kpc, the cluster is located approximately 440 pc above the disk, well within the bulge of the galaxy. Publication: The Astronomical Journal Pub Date: January 1992 DOI: 10.1086/116048 Bibcode: 1992AJ....103..142C Keywords: Giant Stars; Globular Clusters; Infrared Photometry; Stellar Spectrophotometry; Color-Color Diagram; Color-Magnitude Diagram; Galactic Bulge; Metallicity; Astrophysics; GLOBULAR CLUSTERS: INDIVIDUAL: TERZAN 2; TECHNIQUES: PHOTOMETRIC full text sources ADS | data products SIMBAD (8)