Measurements of double stars
 1993.67 - 1998.13

Alzner, A.

doi:10.1051/aas:1998291

Cited by 13 publications

(7 citation statements)

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“…7 (e.g. Heintz 1996, Alzner 1998, ten Brummelaar et al 2000 and observations were made at seeing conditions of about 1 arcsec. As expected, both the 180 o and 270 o offsets produced the best spectra in that Hα shows the broadest wings, hence the least contamination by the faint companion.…”

Section: Visual and Spectroscopic Binariesmentioning

confidence: 99%

Nearby stars of the Galactic disk and halo. III.

2003

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Abstract. High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk -our "familiar Milky Way" -came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy -and by inference many other spirals as well -if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at τ ∼ 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary χ Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the Ursa Major Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though syst...

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Section: Visual and Spectroscopic Binariesmentioning

confidence: 99%

Nearby stars of the Galactic disk and halo. III.

2003

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“…HD 42657: Aikman (1976) detected small radial velocity variations. Alzner (1998) gives a separation of 202. ′′ 8 and a position angle of 5.19 • for a wide companion.…”

Section: Appendix A: Notes On Individual Systemsmentioning

confidence: 99%

Multiplicity of late-type B stars with HgMn peculiarity

Schöller

Correia

Hubrig

et al. 2010

A&A

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Context. Observations at various wavelengths of late B-type stars exhibiting strong atmospheric overabundances of the chemical elements Hg and Mn indicate that these stars are frequently found in binary and multiple systems. Aims. We intend to study the multiplicity of this type of chemically peculiar stars, looking for visual companions in the range of angular separation between 0. 05 and 8 . Methods. We carried out a survey of 56 stars using diffraction-limited near-infrared imaging with NAOS-CONICA at the VLT. Results. Thirty-three companion candidates in 24 binaries, three triples, and one quadruple system were detected. Nine companion candidates were found for the first time in this study. Five objects are likely chance projections. The detected companion candidates have K magnitudes between 5. m 95 and 18. m 07 and angular separations ranging from <0. 05 to 7. 8, corresponding to linear projected separations of 13.5-1700 AU. Conclusions. Our study clearly confirms that HgMn stars are frequently members of binary and multiple systems. Taking into account companions found by other techniques, the multiplicity fraction in our sample may be as high as 91%. The membership in binary and multiple systems seems to be a key point to understanding the abundance patterns in these stars.

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“…HD 281159 ( BD +31 643) is a B5 star primarily responsible for illuminating the IC 348 reflection nebula ( Witt & Schild 1986) and is a 0.47 00 binary (Alzner 1998). Optical coronagraphic images by Kalas & Jewitt (1997) detected a bright linear feature within the IC 348 nebulosity, centered on HD 281159 and with diameter 40 00 , and suggested that this might be a debris disk seen in scattered light.…”

Section: Hd 281159 (Bd +31 643)mentioning

confidence: 99%

The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VI. Perseus Observed with MIPS

Rebull

Stapelfeldt

Evans

et al. 2007

ASTROPHYS J SUPPL S

120

140

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We present observations of 10.6 deg 2 of the Perseus molecular cloud at 24, 70, and 160 m with Spitzer MIPS. The images show prominent, complex extended emission dominated by illuminating B stars on the east side of the cloud and by cold filaments of 160 m emission on the west side. Of 3950 point sources identified at 24 m, 1141 have 2MASS counterparts. A quarter of these populate regions of the K s versus K s À ½24 diagram that are distinct from stellar photospheres and background galaxies and thus are likely to be cloud members with infrared excess. Nearly half (46%) of these 24 m excess sources are distributed outside the IC 348 and NGC 1333 clusters. A significant number of IRAS PSC objects are not recovered by Spitzer MIPS, most often because the IRAS objects were confused by bright nebulosity. The intercluster region contains several tightly clumped (r $ 0:1 pc) young stellar aggregates whose members exhibit a wide variety of infrared SEDs characteristic of different circumstellar environments. This could be explained by a significant age spread among the aggregate members, or if the members formed at the same time, a remarkably rapid circumstellar evolution would be required to account for the association of Class I and Class III sources at ages P1 Myr. We highlight important results for the HH 211 flow, where the bow shocks are detected at both 24 and 70 m, and for the debris disk candidate BD +31 643, where the MIPS data show the linear nebulosity to be an unrelated interstellar feature. Our data, mosaics, and catalogs are available at the Spitzer Science Archive for use by interested members of the community.Note.-Units of right ascension are hours, minutes, and seconds, and units of declination are degrees, arcminutes, and arcseconds. REBULL ET AL. 448 Vol. 171 14 See http://ssc.spitzer.caltech.edu / legacy/ for additional information. 15 Available at http://ssc.spitzer.caltech.edu.Fig. 2.-Mosaic of Perseus map at 24 m. The reverse gray-scale colors correspond to a logarithmic stretch of surface brightnesses.

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Measurements of double stars 1993.67 - 1998.13

Abstract: Abstract. 624 Micrometer Measurements of 224 pairs with a 32.5 cm Cassegrain, 719 Measurements of 310 double stars with a 360 mm Newtonian are given.

Cited by 13 publications

References 0 publications

Nearby stars of the Galactic disk and halo. III.

Nearby stars of the Galactic disk and halo. III.

Multiplicity of late-type B stars with HgMn peculiarity

The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VI. Perseus Observed with MIPS

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