List Of Stars Research Articles

First Byurakan Spectral Sky Survey. Late-type stars. VIII. Zone + 80 ≤ δ ≤ + 90°

The eighth list of late-type stars of spectral classes M and C detected on the plates of the First Byurakan Spectral Sky Survey (FBS) in the zone +80 ≤ δ ≤ +90° is presented. Of the 79 objects detected, 67 are new discoveries (66 M stars and one carbon star); 16 objects are unidentified IRAS sources. The equatorial coordinates, spectral classes, and magnitudes are given.

Astrometric Detection of Extrasolar Planets: Results of a Feasibility Study with the Palomar 5 Meter Telescope

The detection of extrasolar planets around stars like the Sun remains an important goal of astronomy. We present results from Palomar 5 m observations of the open cluster NGC 2420 in which we measure some of the sources of noise that will be present in an astrometric search for extrasolar planets. This is the first time that such a large aperture has been used for high-precision astrometry. We find that the atmospheric noise is 150 micro-arcsec hr(exp 1/2) across a 90 sec field of view and that differential chromatic refraction (DCR) can be calibrated to 128 micro-arcsec for observations within 1 hr of the meridian and 45 deg of zenith. These results confirm that a model for astrometric measurements can be extrapolated to large apertures. We demonstrate, based upon these results, that a large telescope achieves the sensitivity required to perform a statistically significant search for extra planets. We describe an astrometric technique to detect planets, the astrometric signals expected, the role of reference stars, and the sources of measurement noise: photometric noise, atmospheric motion between stars, sky background, instrumental noise, and DCR. For the latter, we discuss a method to reduce the noise further to 66 micro-arcsecond for observations within 1 hr of the meridian and 45 deg of zenith. We discuss optimal lists of target stars taken from the latest Gliese & Jahreiss catalog of nearby stars with the largest potential astrometric signals, declination limits for both telescope accessibility and reduced DCR, and galactic latitude limits for a sufficiant number of reference stars. Two samples are described from which one can perform statistically significant searches for gas giant planets around nearby stars. One sample contains 100 solar class stars with an average stellar mass of 0.82 mass; the other maximizes the number of stars, 574, by searching mainly low-mass M stars. We perform Monte Carlo simulations of the statistical significance of the expected results by using measured and estimated noise quantities. We show the semimajor axis parameter spaces that are searched for each star and how an increase in the length of the observing program expands these spaces. The search over semimajor axis parameter space relates to the theory of gas giant planet formation.

Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center

view Abstract Citations (10) References (6) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center Schmidt, Edward G. ; Carruthers, George R. Abstract Far-ultraviolet photometry is presented for 121 objects in a 20 diameter field centered on ρ Oph and for 649 objects in a field covering the Galactic center. Broadband magnitudes with effective wavelengths of 1375 Å and 1781 Å are given. The Galactic center field overlaps two fields which were discussed in an earlier paper. Eighty- eight percent of the ultraviolet objects in the ρ Oph field were identified with visible stars using the SIMBAD database, while only 9% of the objects are blends of early-type stars too close together to separate with our resolution. The photometric calibration was studied in detail, and corrections for nonlinearity were derived for the fields analyzed earlier as well as those discussed here. For stars in common between the Galactic center field and the previous fields, a comparison of the magnitudes yielded estimates of the internal errors of the magnitudes of σ1375 = 0.13 mag and σ1781 = 0.21 mag. A collated list of stars in the fields covering the Galactic center and incorporating the revised calibration is presented and compared with the S20l data of the same region. The properties of the sample of ultraviolet objects in the σ Oph field are briefly commented upon. Publication: The Astrophysical Journal Supplement Series Pub Date: May 1996 DOI: 10.1086/192294 Bibcode: 1996ApJS..104..101S Keywords: GALAXY: CENTER; ISM: INDIVIDUAL NAME: RHO OPHIUCHI; STARS: FUNDAMENTAL PARAMETERS; SURVEYS; ULTRAVIOLET: STARS full text sources ADS | data products SIMBAD (1759) CDS (2) MAST (1) Related Materials (1) Catalog: 1996yCat..21040101S

SPACE MOTIONS OF LOW-MASS STARS. II: RADIAL VELOCITIES

ABSTRACT Radial velocities are presented for 53 dwarf K and M stars, eight of which are radial velocity standards. This is the second list in a program to determine space motions for all of the stars in the McCormick lists of dwarf stars. The observations reported here differ from those of the first list in that they were made using the 1.88m David Dunlap reflector. One of the stars varies in radial velocity, consistent with a spectroscopic binary with a period of about 48 days.

THE ABSOLUTE FLUX CALIBRATION OF THE UVBY PHOTOMETRIC SYSTEM

ABSTRACT We present the absolute flux calibration for the uvby photometric system passbands, derived from homogeneous spectroscopic and photometric standard star lists, and referred to the Vega absolute flux calibration of Hayes (1985).

The first byurakan spectral sky survey. Late spectral class stars. VII. The zone +76° ≤ δ ≤ +80°

We present the seventh list of stars of the late M and C spectral classes taken from the plates of the First Byurakan Spectral Sky Survey (FBS). Data on 24 objects, 2 of which are carbon stars of early subclasses (R-stars), are given for the first time. The spectral membership of two known stars is established. The objects lie in the zone 3h 40m ≤ α ≤ 18h 30m and +76° ≤ δ ≤ +80°.

The First Byurakan Spectral Sky Survey. Late-type stars. VI. The zone+69°≤δ≤+77°

We present the sixth list of red stars selected from the plates of the First Byurakan Spectral Sky Survey. These objects are located in the zone3 h 45 m ≤α≤18 h and+69°≤δ≤+77°. The list contains data on 42 new objects. We suggest that there exists a dust cloud around 2 of them.

Circumstellar molecular line absorption and emission in the optical spectra of post-AGB stars

We present a list of post-AGB stars showing molecular line absorption and emission in the optical spectrum. Two objects show CH+, one in emission and one in absorption, and 10 stars show C2 and CN in absorption. The Doppler velocities of the C2 lines and the rotational temperatures indicate that the line forming region is the AGB remnant. An analysis of the post-AGB stars of which CO millimeter data is available suggests that the C2 expansion velocity is of the same order as the CO expansion velocity. HD 56126 has been studied in detail and we find a mass-loss rate of M=2.8 × 10−4 M⊙yr−1,\(f_{C_2 } \) = 2.4 × 10−8 and f CN = 1.3 × 10−8. The mass-loss derived from C2 is significantly larger than M=1.2 × 10−5 M⊙yr−1 derived from CO. We find that all objects with the 21µm feature in emission show C2 and CN absorption, but not all objects with C2 and CN detections show a 21µm feature.

Confor Program: Determination of Relative Orientation Parameters Between VLBI and FK5 Reference Frames

The primary goal of the CONFOR Program (CONnection of Frames in Optics and Radio) is to study the connection between VLBI and traditional optical reference frames as well as to study regional features of the FK5 (Gubanov, Kumkova & Tel'nyuk-Adamchuk, 1990). The main concept of this program is the usage of fixed systems of reference stars in field containing the extragalactic radio sources (ERS) and as a result the creation of a reliable base for astrometric reduction of photographic plates with ERS images. Fulfillment of the Program is embracing several stages.1. Star lists have been prepared of 2575 both intermediate reference stars and radio stars for meridian observations and about 7 thousand stars of 12-14 mag. for astrographic observations in 238 fields with extragalactic compact radio sources.2. Observations have been organized of these stars with meridian circles and astrographs in several Eastern observatories (Kyiv, Odesa, Bucharest, Mykolaiv, Kharkiv). The meridian observations are finished in Kyiv and Odesa. Positions of radio stars were determined from Kyiv meridian observations (two epochs: 1984 and 1990).3. Databases of both the optical and radio interferometric observations have been compiled of radio stars, ERS as well as optical observations of intermediate stars in the fields centered in ERS.4. Observations were carried out with several astrographs (Kyiv, Bucharest, Abastumany, Tautenburg, Kitab, Sanglok) and positions were determined of 57 ERS.5. Determination was carried out of the angles of relative orientation between VLBI and FK5 reference frames as well as estimation of regional features of the FK5. For this purpose both collected and original radio source coordinates were used.This work was supported by grant of Academy of Sciences of former Soviet Union and ISF grant U52000.

An unrecorded medieval astrolabe quadrant from c. 1300

Summary A detailed description of an as yet unrecorded astrolabe quadrant in a private collection is presented. A date between 1291 and 1310 is deduced from the calendrical data engraved on it. The characteristics of the newly recorded instrument have been compared with those of six other medieval astrolabe quadrants. The newly recorded instrument appears to present an early, if not the earliest, stage of development in the history of the astrolabe quadrant. In the comparison the newly recorded instrument is also distinguished by the red and black colours applied to differentiate between the superposed scales of the astrolabe quadrant. The names and the positions of the stars on the instruments were used to establish a connection between two of the instruments studied, those in Rouen and Oxford, and a manuscript tradition on the construction of the astrolabe quadrant, exemplified by MS Oxford Ashmole 1522. The data on three other astrolabe quadrants are shown to stem from star lists in treatises on astrol...

A Very Active T Tauri Star in NGC 7129

The star forming region NGC 7129 was first studied by Herbig (1960), who discovered two bright (BD+65° 1637 and LkHα234) and some weaker Hα emission stars. Subsequent investigations in this region led to the detection of five Herbig-Haro objects (Strom et al. 1974, Gyulbudaghian et al. 1978, Eiroa et al. 1992) and one T Tauri star, V350 Cep (Gyulbudaghian & Sarkissian 1977). Some non-stable stars in NGC 7129 are surrounded by reflection and cometary nebulae.Our Hα-emission survey (Semkov &: Tsvetkov 1986) revealed an interesting irregular variable star in the dark clouds near the emission nebulae. On objective prism plates the star shows very strong Hα-emission and was included in our list of such stars as No. 7. An identification chart and the coordinates can be found in Semkov (1993a). The observations reported here include long-time photographic photometry and CCD spectroscopic and photometric observations.

Ultraviolet classification of Wolf-Rayet stars

The ultraviolet spectra of 94 WR stars obtained from Vilspa IUE archive are used here to look for classification criteria in the UV region alone. We have tried to select as many single and SB1 type stars as possible in the Galaxy and the LMC to get the complete, flux-calibrated spectra between 1150 and 3250 Å. Altogether 56 (34 of WN and 22 of WC type) stars in the Galaxy and 38 (31 of WN and 7 of WC type) in the LMC were found, for which at least single SWP and LWR (or LWP) low resolution images are accessible – note that this is about one third of the number of known galactic and LMC WR stars. The set of stars we study is representative according to spectral subtype and brightness (it is almost complete to 12 magnitude for galactic stars). See Niedzielski & Rochowicz (1994) for the list of program stars and associated IUE images as well as for the details of reduction.To look for classification criteria of WR stars in the ultraviolet region we will use the equivalent width (EW) and line width (FWHM) data.

The first Byurakan Spectral Sky Survey. Stars of later spectral classes. V. The zone +65°⩽δ⩽+69°

We give the fifth list of red stars of the First Byurakan Spectral Sky Survey. The objects are located in the zone 5h ⩽ α ⩽ 18h 30m and +65‡ ⩽ δ ⩽ +69‡. The list contains the data on 18 new objects, one of which is a star of class R. We also give the first determination of the spectral class of 11 variable objects, for four of which we give the spectrograms in the range of wavelengths 4700–6700a.

List of stars recommended as spectrophotometric standards

Based on long-term observations of the absolute energy distribution in stellar spectra (starting in 1975), and from a survey of the literature, 14 stars of early spectral type (B7 III–A7 V) were selected. The constancy of their brightness is beyond any doubt now. These stars, with visual magnitudes 0.0 to 4.8, can be recommended as spectrophotometric standards for the spectral region 310–750 nm.

"Democracy and Burnt Cork": The End of Blackface, the Beginning of Civil Rights

THE NEW DEAL brought the immigrant to the center of American politics. Shifting the orientation of the majority party from the hinterland to the metropolis, Franklin D. Roosevelt's victories were foreshadowed by the Catholic Al Smith's 1928 run for the presidency. The 1930s and 1940s were also the golden age of the Hollywood studio system, with the coming of talking pictures. In the standard film-history accounts, urban, Americanizing immigrants watched massproduced, studio-made, genre films purveying the quintessential national narratives-gangster pictures, musicals, screwball comedies, domestic melodramas, westerns. The 1930s left its mark on the genre mix, from this point of view, bringing together the urban milieu of gangster films and screwball comedy's class reconciliation-the movies of Frank Capra celebrating populist politics, on the one hand, and the cinema of escapist entertainment allowing moviegoers to flee the Depression, on the other. Some of the most important and popular films of the period are missing from this picture: films grounded in race. As the Jazz Age came to an end, Al Jolson's blackface TheJazz Singer (1927) and The Singing Fool (1928) broke all existing box office records. At the same time thatJolson was the top Hollywood box office star, Amos 'n' Andy was the most popular radio show. The Motion Picture Exhibitors' coveted top ten list of stars was headed in 1934 by Will Rogers, who put on Stepin Fetchit's blackvoice in the southernJudge Priest (1934); from 1935 through 1938 by Shirley Temple, who starred in a series of Civil War southerns with Bojangles Robinson (and put on blackface in one of them); and in 1939 by Mickey Rooney, who led a blackface minstrel show that year in Babes in Arms. Far from being a blockbuster exception to New Deal cinema, David 0. Selznick's Gone with the Wind (1939), the most popular film in Hollywood's first half century, proves the rule.' TheJazz Singer and Gone with the Wind were transformative films in the history of Hollywood, combining box office success, critical recognition of innovative significance, and shifts in the cinematic mode of production. The two earlier revolutionary moments in film history similarly addressed the fundamental conflict in American history, given in Winthrop Jordan's formulation as white over black; they also show, in Edmund Morgan's terms, how American freedom was born from American slavery. I have in mind the Edwin S. Porter trilogy of

The absolute proper motion of 79 stars from humphreys's list of stars in associations

Abstract The absolute proper motions of 79 stars from Humphreys's catalogue of the stars in associations are derived. Proper motions are calculated for J2000.0 and for the epoch of observations in FK5 system.

The absolute proper motion of 79 stars from humphreys's list of stars in associations

The absolute proper motion of 79 stars from humphreys's list of stars in associations

Period dependent variations of the shell spectrum of V923 AQL

V923 Aql is a well known Be star with strong shell spectrum. It was included in the list of shell stars of Merrill and Burwell (1949). A detailed study of the radial velocity variations in the spectrum of the star based on wide collection of spectral observations was presented in the work of Koubsky et al. (1988). In this work an orbital period of 214.756 days was suggested for the binary system consisting of a B5–7 primary and low mass (0.5 Msol).

VLBI observations of a strong radio flare in HR 1099

In 1991 July, we studied a strong radio flare in the RS CVn system HR 1099 with VLBI techniques. This system is one in a list of stars which we regularly monitor with the Noto 32-m antenna at 6 cm. The angular size of the radio source was found to increase at the beginning of the flare. It reached about 4 mas, which corresponds to a linear size comparable to that of the entire binary system. An upper limit of 80 G for the magnetic field was derived. The flare decay reflects the change of the power spectrum of the emitting electrons towards lower energies, due to radiative losses and interaction with the local plasma

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