VLBI Astrometry of Radio Stars to Link Radio and Optical Celestial Reference Frames. I. HD 199178 $\&$ AR Lacertae

Abstract

To accurately link the radio and optical Celestial Reference Frames (CRFs) at optical bright end, i.e., with Gaia G band magnitude < 13, increasing number and improving sky distribution of radio stars with accurate astrometric parameters from both Very Long Baseline Interferometry (VLBI) and Gaia measurements are mandatory. We selected two radio stars HD 199178 and AR Lacertae as the target for a pilot program for the frame link, using the Very Long Baseline Array (VLBA) at 15 GHz at six epochs spanning about 1 year, to measure their astrometric parameters. The measured parallax of HD 199178 is $8.949\pm 0.059$ mas and the proper motion is ${\mu }_{\alpha }cos\delta =26.393\pm 0.093$, ${\mu }_{\delta }=-0.950\pm 0.083masy{r}^{-1}$, while the parallax of AR Lac is $23.459\pm 0.094$ mas and the proper motion is ${\mu }_{\alpha }cos\delta =-51.906\pm 0.138$, ${\mu }_{\delta }=46.732\pm 0.131masy{r}^{-1}$. Our VLBI measured astrometric parameters have accuracies about 4-5 times better than the corresponding historic VLBI measurements and comparable accuracies with those from Gaia, validating the feasibility of frame link using radio stars. With the updated astrometric parameters for these two stars, there is a 25% reduction of the uncertainties on the Y axis for both orientation and spin parameters.

arXiv comment11 pages, accepted by MNRAS on 2023 April 20

References in corpus (15)

• DiFX: A software correlator for very long baseline interferometry using multi-processor computing environments
• The third realization of the International Celestial Reference Frame by very long baseline interferometry
• Gaia Data Release 2: The Celestial reference frame (Gaia-CRF2)
• Trigonometric Parallaxes of Massive Star Forming Regions: I. S 252 & G232.6+1.0
• A catalog of chromospherically active binary stars (third edition)
• Parsec-Scale Blazar Monitoring: Flux and Polarization Variability
• The Gaia reference frame for bright sources examined using VLBI observations of radio stars
• Polarization calibration techniques for new-generation VLBI
• VLA+PT Astrometry of 46 Radio Stars
• Radio Stars: from kHz to THz
• Astrometric Positions and Proper Motions of 19 Radio Stars
• Starspot activity of HD 199178. Doppler images from 1994--2017
• Using radio stars to link the Gaia and VLBI reference frames
• The Radio Corona of AR Lacertae
• Third components with elliptical orbits in the eclipsing binaries

Cited by in corpus (3)

• Time-lapse Very Long Baseline Interferometry Imaging of the Close Active Binary HR 1099
• VLBI Astrometry of Radio Stars to Link Radio and Optical Celestial Reference Frames: Observing Strategies
• Validating the bright Gaia celestial reference frame with new VLBI astrometry of radio stars