Your search
Results 6 resources
-
The Differential Speckle Survey Instrument (DSSI) has been successfully operating at the ARC 3.5-m telescope at Apache Point Observatory in New Mexico for over a year, providing diffraction-limited imaging in the optical. We report on commissioning efforts for two new upgrades to DSSI: 1) an internal slit mask for astrometric calibration, and 2) a near-infrared channel configuration for the instrument operating at ~1.5µm. The near-infrared channel takes the place of one of the original optical channels, while the second channel of the instrument remains configured for optical observations. However, a two-position stage has been added to this optical channel, allowing for both of the original 692nm and 880nm filters. This represents the first near-infrared diffraction-limited imaging ever performed with DSSI, and the first for the ARC 3.5-m telescope, and a major step toward routine optical+NIR simultaneous speckle imaging for a range of science projects. The benefits of the internal slit mask and near-infrared channel configuration include improved astrometric precision, reduced time on-sky for calibrations, improved detection of lower luminosity companions including brown dwarfs, and a greater wavelength span for more robust source color determinations and H-R diagram positioning of system components.
-
With observations from data sets available to the REsearch Consortium On Nearby Stars (RECONS, http://www.recons.org), we seek to define the orbits of several K dwarf multiple star systems. When compared to their more massive and less massive counterparts in G and M dwarfs, respectively, K dwarfs remain chiefly overlooked, merely due to the scarcity of data obtained on this stellar type. We address the sizes and shapes of the orbits, as established by their periods and eccentricities. The use of system separation, position angle, and magnitude, obtained from both our program measurements and the literature, will allow orbital construction, from which we ultimately derive the fundamental parameter, the mass. This work has been supported by NSF grants AST-1909560 and AST-1910130.
-
Results from the Gaia satellite provide a new way to obtain a comprehensive assessment of local stellar populations, including, for example, a determination of how frequently nearby stars have orbiting stellar companions. The RECONS K Star (RKSTAR) Survey is attempting to answer this question by examining the multiplicity of more than 5000 systems with K dwarf primaries within 50 parsecs of our Solar System. Three surveys (Wide Field, Speckle, and Radial Velocity) will detect stellar and planetary companions to K dwarfs at separations of 0.1 to 1000 AU. This poster will detail the Wide Field portion using Gaia data releases to assemble a list of stellar companion candidates at separations larger than 1 arcsecond from their primary stars, and has revealed nearly 500 companions. These are then cross-referenced with the Washington Double Star Catalogue, the most comprehensive catalog of known multiple stars available, to confirm about 400 known companions and reveal that about 80 are new discoveries. Preliminary findings of this cross-catalogue comparison will be presented. This assessment of the nearest K dwarfs will be helpful in future exoplanet surveys and will serve to inform theories on stellar and planetary formation. This work has been supported by NSF grant AST-1909560.
-
The Differential Speckle Survey Instrument (DSSI) was built in 2008 and in its first 14 years saw substantial use in diffraction-limited imaging projects at the WIYN Telescope, Gemini-N and Gemini-S, and the Lowell Discovery Telescope. However, the completion and commissioning of the QWSSI speckle camera at Lowell Observatory has recently created the opportunity to move DSSI to the ARC 3.5-m Telescope at Apache Point Observatory (APO) in New Mexico. We report here on the commissioning of DSSI at APO and discuss some of the early science results, which represent the first diffraction-limited images in the visible range ever obtained at the ARC Telescope. Our initial observations appear to be comparable to DSSI's earlier use at WIYN in that we can obtain 0.05-arcsecond resolution at 692 nm for stars as faint as 12th magnitude in five minutes of observing or less, and we can detect companions with magnitude differences of 4 to 5 relative to their primary stars. In the near term, the instrument will be used (1) to supplement observations for the RECONS K Stars project to survey nearby K dwarfs for companions and (2) to obtain follow-up observations of binaries identified by Kepler, TESS, APOGEE, and other sources. It will also provide a testbed for simultaneous visible and infrared speckle imaging and speckle imaging through coherent fiber bundles. The potential advantages of these two innovations include better photometry in the diffraction-limited regime and higher-quality image reconstructions overall. We gratefully acknowledge support from National Science Foundation grants AST-1909560 and AST-1910130, as well as a SEED grant from the Research Corporation for Science Advancement, in the completion of this work.
-
As its periastron passage occurred during the third quarter of 2020, system 24 Aqr is of particular significance. New visual solutions for the latest speckle interferometry observations collected by the Lowell Discovery Telescope (LTD) with its new QWSSI speckle camera are presented here. A variety of techniques were used to analyze the system, including ORBITX code for orbital solution, Al-Wardat’s method for analyzing multiple stellar systems, and Edwards’ method for analyzing visual and spectroscopic binaries. We derive precise masses and the complete set of its fundamental parameters for the three components, and we introduce a new orbital solution, and a new dynamical parallax, which is very close to the measured value given by Hipparcos 2007 and from that of Gaia DR2. In the next section, we discuss the possibility of a coplanar orbit. In conclusion, we demonstrate that we need a 65-m telescope to resolve the inner binary visually, although an array of telescopes could be used instead.