HD 92987 Archives

Illustration of the positions and proper motions that Hipparcos and Gaia would measure for the same hypothetical orbit but with six different periods. The orbits shown have had parallactic and proper motion removed (c.f. Figure 1). The small colored ellipses show the quasi-one-dimensional position measurements made by Hipparcos and Gaia, the diamonds show the best-fit positions at Jyr 1991.25 and 2016.0 from fitting straight lines to the blue and orange points, respectively, and the arrows show the best-fit proper motions. The portions of the orbit covered by Hipparcos and Gaia are indicated by shading on the orbit, and a black arrow indicates the (counterclockwise) direction of orbital motion. Differences between the Hipparcos proper motion, the Gaia proper motion, and the scaled difference between the Hipparcos and Gaia positions can constrain orbital motion. At short periods (top middle and especially top left), the positions and proper motions can bear little resemblance to the instantaneous position and proper motion at the average epoch of observation, while at long periods (lower right) this distinction becomes insignificant. For all periods shown other than 50 years the star completes more than one full orbit between the Hipparcos and Gaia central epochs. -- astro-ph.IM

Astronomy & Telescopes, Brown Dwarfs, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Stellar Cartography

Astrometry As A Tool For Discovering And Weighing Faint Companions To Nearby Stars

by Keith CowingJune 21, 2024June 21, 2024

This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to measure the […]

HD 92987

Astrometry As A Tool For Discovering And Weighing Faint Companions To Nearby Stars

Opportunity to Contribute to NASA DARES Community White Paper on Phototrophic Biosignatures

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