Speckle Interferometry at SOAR in 2024 and 2025
Andrei A. Tokovinin, Brian D. Mason, Rene A. Mendez, Edgardo Costa · 2026 · 242 citationsRead the paper
Abstract Results of speckle interferometry observations at the 4.1 m Southern Astrophysical Research telescope obtained during 2024–2025 are presented. We present 5316 measurements of relative positions and magnitude differences in 3532 pairs (including 524 unpublished measures made before 2024) with median and minimum separations of 0 . ″ 19 and 12 mas, respectively; nonresolutions of 1723 stars are documented as well. More than 400 pairs have been resolved here for the first time and not resolved by Gaia; among those are 222 TESS objects of interest, 46 inner subsystems in known wider binaries within 100 pc, and 43 subdwarfs. Positional measurements are used to compute or improve binary orbits; elements of 202 orbits with meaningful errors are given here, while preliminary and tentative orbits are published elsewhere. Of special note are orbits with large and accurately measured eccentricities (e.g., e = 0.9866 ± 0.0014 for J13038−2035) and orbits of pre-main-sequence binaries. The Appendix contains parameters of 86 binaries used for calibration of pixel scale and orientation.
What the full text shows
Tested in real conditions- Resolved a large number of binary pairs, including many not resolved by Gaia. — 3532 pairs (5316 measurements), with >400 resolved for the first time (Observations at the 4.1 m SOAR telescope using HRCam)
- Achieved high angular resolution for close binary systems. — Minimum separation of 12 mas; median separation of 0.19 arcsec (Speckle interferometry)
- Resolved specific categories of objects not captured by Gaia. — 222 TESS objects of interest, 46 inner subsystems in wide binaries (<100 pc), and 43 subdwarfs (New resolutions in 2024-2025)
- Computed or improved binary orbits with meaningful errors. — 202 orbits (Based on positional measurements)
- Measured high eccentricity in specific binary orbits. — e = 0.9866 ± 0.0014 (For object J13038−2035)
- Documented non-resolutions of stars to establish resolution limits. — 1723 stars (Mostly reference stars)
- Setup
- 4.1 m SOAR telescope with HRCam; used I (824/170 nm) and Strömgren y (543/22 nm) filters; 21 observing runs in 2024-2025.
- How
- Speckle interferometry using the HRCam high-resolution camera on the 4.1 m SOAR telescope. Data reduction involved speckle power spectrum modeling and averaging of data cubes to determine relative positions and magnitude differences.
- Limitations
- Internal errors are smaller than real external errors · Position angle is measured modulo 180 degrees unless the true quadrant is determined · Magnitude difference bias caused by speckle anisoplanatism for wide pairs
Summarized by Gemma 4 from the open-access full text · 8 Oct 2026. Read it