Search Publications
On the distance to the Ophiuchus star-forming region
Mamajek, E. E.
The Ophiuchus molecular cloud complex has produced in Lynds 1688 the richest known embedded cluster within ∼300 pc of the Sun. Unfortunately, distance estimates to the Oph complex vary by nearly ∼40% (∼120-165 pc). Here I calculate a new independent distance estimate of 135 ± 8 pc to this benchmark star-forming region based on Hipparcos trigonomet…
Speckle observations with PISCO in Merate: IV. Astrometric measurements of visual binaries in 2005
Scardia, M.; Prieur, J. -L.; Pansecchi, L. +6 more
We present relative astrometric measurements of visual binaries made during the second semester of 2005, with the speckle camera PISCO at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. The purpose of this long term program is to impro…
New absolute magnitude calibrations for detached binaries
Demircan, O.; Eker, Z.; Soydugan, F. +6 more
Lutz-Kelker bias corrected absolute magnitude calibrations for the detached binary systems with main-sequence components are presented. The absolute magnitudes of the calibrator stars were derived at intrinsic colours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As for the calibrator stars, 44 detached binaries wer…
A revisit to agglomerates of early-type Hipparcos stars
Caballero, J. A.; Dinis, L.
% We study the spatial structure and sub-structure of regions rich in {Hipparcos} stars with blue B_T-V_T colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clust…
Preliminary orbital elements of six visual binary stars
Scardia, M.; Prieur, J. -L.; Pansecchi, L. +1 more
Preliminary new orbital elements were computed for the visual binary stars A 1 - ADS 1345, A 2629 - ADS 3610, BU 560 - ADS 4371, STF 3115 - ADS 4376, STF 1426 AB - ADS 7730 and STF 2437 - ADS 11956. Using Straizys and Kuriliene's data, we derived new formulae for computing dynamical parallaxes for luminosity classes IV and V. The values found for …
Thread safe astronomy
Seaman, R.
Observational astronomy is the beneficiary of an ancient chain of apprenticeship. Kepler's laws required Tycho's data. As the pace of discoveries has increased over the centuries, so has the cadence of tutelage (literally, "watching over"). Naked eye astronomy is thousands of years old, the telescope hundreds, digital imaging a few decades, but to…
Local Galactic kinematics from revised Hipparcos catalogue
Zhu, Z.; Yuan, F. -T.; Kong, D. -L.
Local stellar kinematic properties are reinvestigated. A main-sequence sample of 12718 objects is picked out from a total of 117955 Hipparcos stars and some local kinematical parameters are re-determined by dividing 19 subsamples mainly according to color index. The results are reasonably consistent with those derived from the initial Hipparcos da…