Observations of Binary Stars with the Differential Speckle Survey Instrument. IX. Observations of Known and Suspected Binaries, and a Partial Survey of Be Stars

Abstract

We report 370 measures of 170 components of binary and multiple star systems, obtained from speckle imaging observations made with the Differential Speckle Survey Instrument at Lowell Observatory's Discovery Channel Telescope in 2015 through 2017. Of the systems studied, 147 are binary stars, 10 are seen as triple systems, and 1 quadruple system is measured. Seventy-six high-quality non-detections and fifteen newly resolved components are presented in our observations. The uncertainty in relative astrometry appears to be similar to our previous work at Lowell, namely linear measurement uncertainties of approximately 2 mas, and the relative photometry appears to be uncertain at the 0.1 to 0.15 magnitude level. Using these measures and those in the literature, we calculate six new visual orbits, including one for the Be star 66 Oph, and two combined spectroscopic-visual orbits. The latter two orbits, which are for HD 22451 (YSC 127) and HD 185501 (YSC 135), yield individual masses of the components at the level of 2 percent or better, and independent distance measures that in one case agrees with the value found in the Gaia DR2, and in the other disagrees at the 2-σ level. We find that HD 22451 consists of an F6V+F7V pair with orbital period of 2401.1 ± 3.2 days and masses of 1.342 ± 0.029 and 1.236 ± 0.026 M ⊙ . For HD 185501, both stars are G5 dwarfs that orbit one another with a period of 433.94 ± 0.15 days, and the masses are 0.898 ± 0.012 and 0.876 ± 0.012 M ⊙ . We discuss the details of both the new discoveries and the orbit objects.

Surveying the Bright Stars by Optical Interferometry. II. A Volume-limited Multiplicity Survey of Main-sequence F Stars

“…Returning to the Aa,Ab pair, we note there are 26 resolved observations of this pair listed in the INT4, including those made by HIPPARCOS, speckle, and the NPOI (Paper I). Horch et al (2020) provide additional observations (2015.8365) made at 692 and 880 nm. We examined six nights of archival NPOI data between 2009 Jul 07 UT and 2009 Jul 22 UT using the standard GRID-FIT procedure, but obtained a significant χ 2 ν minimum ( § 5) on only one night, with the results for the six nights varying widely in separation and position angle.…”

“…From the available evidence, we conclude 66 Oph consists of only two physical stellar components, the AB pair. 5) are shown, along with additional observations from the INT4 (and references therein) and Horch et al (2020). The apparent orbit corresponding to the best-fit orbital solution to these points (Table 6) is overplotted.…”

“…We examined 21 nights of archival NPOI data (2006 -2011) using GRIDFIT, obtaining significant detections ( § 5) on 12 nights during 2006, 2007). We then proceeded to detailed modeling of the data from each of the 12 nights with OYSTER using fixed stellar angular diameters of θ P = 0.3 mas (from the NPOI planning software) and θ S = 0.13 mas, estimated from the component spectral type ("early A") suggested by Horch et al (2020), and stellar radii given by Schmidt-Kaler (1982), along with the nightly ρ and θ values and the average ∆m 700 obtained from GRIDFIT as inputs. The results of the nightly fits are presented in Table 5 and Figure 6.…”

“…We can use the ∆m 700 value, along with the spectral type B2Ve (Horch et al 2020, and BeSS) and v sini = 262 km s −1 (BeSS) for the primary, and the above cited orbital inclination, to estimate some of the properties of the binary components. The models of Townsend et al (2004, and Lastly, we fit a new orbit (Table 6 and Figure 6) to the combination of our nightly position fits, those of Horch et al (2020), and all but one of the resolved INT4 observations, the excluded observation having a very large separation error (± 50 mas, Oudmaijer & Parr 2010). The orbital elements of Table 6 are quite similar to those of Horch et al (2020), but with significantly smaller errors, and provide a significantly better fit to all the observations prior to 2011 (Figure 6).…”

“…The INT4 lists component A as unresolved on 10 dates (1975 -1994) implying ρ < 24 mas in the visible, and Horch et al (2020) also lists it as unresolved (2015.8338) at a 692 nm with detection limit of ∆m of 3.66 at 200 mas. The five nights of NPOI observations of γ Cas listed in Table 4 were modeled with GRIDFIT with null result; while the GRIDFIT minima met our significance criteria ( § 5), the indicated angular separations were well below the angular resolution of the baselines used in the observations (Table 1), hence indicating a single source.…”