VLBI FOR GRAVITY PROBE B . V. PROPER MOTION AND PARALLAX OF THE GUIDE STAR, IM PEGASI
| Autor: | J.-F. Lestrade, Irwin I. Shapiro, R. R. Ransom, D. E. Lebach, Michael Bietenholz, Norbert Bartel, M. I. Ratner |
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| Přispěvatelé: | Observatoire de Paris, Université Paris sciences et lettres (PSL) |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Physics
[PHYS]Physics [physics] Proper motion 010308 nuclear & particles physics FOS: Physical sciences Astronomy and Astrophysics Astrophysics 01 natural sciences Declination Space and Planetary Science 0103 physical sciences Orbital motion Very-long-baseline interferometry International Celestial Reference Frame Astrophysics - Instrumentation and Methods for Astrophysics Right ascension Parallax [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] 010303 astronomy & astrophysics Instrumentation and Methods for Astrophysics (astro-ph.IM) ComputingMilieux_MISCELLANEOUS Reference frame |
| Zdroj: | Astrophysical Journal Supplement Astrophysical Journal Supplement, American Astronomical Society, 2012, 201 (1), pp.5. ⟨10.1088/0067-0049/201/1/5⟩ |
| ISSN: | 0067-0049 1538-4365 |
| DOI: | 10.1088/0067-0049/201/1/5⟩ |
| Popis: | We present the principal astrometric results of the very-long-baseline interferometry (VLBI) program undertaken in support of the Gravity Probe B (GP-B) relativity mission. VLBI observations of the GP-B guide star, the RS CVn binary IM Pegasi (HR 8703), yielded positions at 35 epochs between 1997 and 2005. We discuss the statistical assumptions behind these results and our methods for estimating the systematic errors. We find the proper motion of IM Peg in an extragalactic reference frame closely related to the International Celestial Reference Frame 2 (ICRF2) to be -20.83 +- 0.03 +- 0.09 mas/yr in right ascension and -27.27 +- 0.03 +- 0.09 mas/yr in declination. For each component the first uncertainty is the statistical standard error and the second is the total standard error (SE) including plausible systematic errors. We also obtain a parallax of 10.37 +- 0.07 mas (distance: 96.4 +- 0.7 pc), for which there is no evidence of any significant contribution of systematic error. Our parameter estimates for the ~25-day-period orbital motion of the stellar radio emission have SEs corresponding to ~0.10 mas on the sky in each coordinate. The total SE of our estimate of IM Peg's proper motion is ~30% smaller than the accuracy goal set by the GP-B project before launch: 0.14 mas/yr for each coordinate of IM Peg's proper motion. Our results ensure that the uncertainty in IM Peg's proper motion makes only a very small contribution to the uncertainty of the GP-B relativity tests. Comment: Accepted for publication in the Astrophysical Journal Supplement Series |
| Databáze: | OpenAIRE |
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