Searcharxiv⌕ Search

arXiv subjects

Arnold R. Klemola

Publications and source records attributed to Arnold R. Klemola.

2 recordsLinked to original sources

Lick Northern Proper Motion Program. III. Lick NPM2 Catalog

The Lick Northern Proper Motion (NPM) program, a two-epoch (1947-1988) photographic survey of the northern two-thirds of the sky (Dec. > -23 deg), has measured absolute proper motions, on an inertial system defined by distant galaxies, for 380,000 stars from 8 14) anonymous stars for astrometry and galactic studies, 92,000 bright (B < 14) positional reference stars, and 35,000 special stars chosen for astrophysical interest. The NPM2 proper motions are on the ICRS system, via Tycho-2 stars, to an accuracy of 0.5 mas/yr in each field. RMS proper motion precision is 6 mas/yr. Positional errors average 80 mas at the mean plate epoch 1968, and 200 mas at the NPM2 catalog epoch 2000. NPM2 photographic photometry errors average 0.18 mag in B, and 0.20 mag in B-V. The NPM2 Catalog and the updated (to J2000) NPM1 Catalog are available at the CDS Strasbourg data center and on the NPM WWW site (http://www.ucolick.org/~npm). The NPM2 Catalog completes the Lick Northern Proper Motion program after a half-century of work by three generations of Lick Observatory astronomers. The NPM Catalogs will serve as a database for research in galactic structure, stellar kinematics, and astrometry.

astro-ph↗

HST Fine Guidance Sensor Astrometric Parallaxes for Three Dwarf Novae: SS Aurigae, SS Cygni, and U Geminorum

We report astrometric parallaxes for three well known dwarf novae obtained using the Fine Guidance Sensors on the Hubble Space Telescope. We found a parallax for SS Aurigae of Pi = 5.00 +/- 0.64 mas, for SS Cygni we found Pi = 6.02 +/- 0.46 mas, and for U Geminorum we obtained Pi = 10.37 +/- 0.50 mas. These represent the first true trigonometric parallaxes of any dwarf novae. We briefly compare these results with previous distance estimates. This program demonstrates that with a very modest amount of HST observing time, the Fine Guidance Sensors can deliver parallaxes of unrivaled precision.

astro-ph↗