ARMADA. II. Further Detections of Inner Companions to Intermediate-mass Binaries with Microarcsecond Astrometry at CHARA and VLTI

Gardner, Tyler; Monnier, John D.; Fekel, Francis C.; Bouquin, J.-B. Le; Scovera, Adam; Schaefer, Gail H.; Kraus, Stefan; Adams, Fred C.; Anugu, Narsireddy; Berger, Jean–Philippe; Brummelaar, T. ten; Davies, Claire L.; Ennis, Jacob; Gies, Douglas R.; Johnson, Keith J. C.; Kervella, P.; Kratter, Kaitlin M.; Labdon, Aaron; Lanthermann, Cyprien; Setterholm, Benjamin R.

doi:10.3847/1538-3881/ac8eae

Cited by 7 publications

(4 citation statements)

References 58 publications

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“…For both the uniform and limb-darkened disks, the values presented here have had a factor of 1.0054 ± 0.0006 divided from them, in accordance with a scaling found by Gardner et al (2022) and an update by J. Monnier (2023, private communication).…”

Section: Angular Diametersupporting

confidence: 86%

Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog

Korolik,

Roettenbacher,

Fischer

et al. 2023

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To accurately characterize the planets a star may be hosting, stellar parameters must first be well determined. τ Ceti is a nearby solar analog and often a target for exoplanet searches. Uncertainties in the observed rotational velocities have made constraining τ Ceti’s inclination difficult. For planet candidates from radial velocity (RV) observations, this leads to substantial uncertainties in the planetary masses, as only the minimum mass ( m sin i ) can be constrained with RV. In this paper, we used new long-baseline optical interferometric data from the CHARA Array with the MIRC-X beam combiner and extreme precision spectroscopic data from the Lowell Discovery Telescope with EXPRES to improve constraints on the stellar parameters of τ Ceti. Additional archival data were obtained from a Tennessee State University Automatic Photometric Telescope and the Mount Wilson Observatory HK project. These new and archival data sets led to improved stellar parameter determinations, including a limb-darkened angular diameter of 2.019 ± 0.012 mas and rotation period of 46 ± 4 days. By combining parameters from our data sets, we obtained an estimate for the stellar inclination of 7° ± 7°. This nearly pole-on orientation has implications for the previously reported exoplanets. An analysis of the system dynamics suggests that the planetary architecture described by Feng et al. may not retain long-term stability for low orbital inclinations. Additionally, the inclination of τ Ceti reveals a misalignment between the inclinations of the stellar rotation axis and the previously measured debris disk rotation axis (i disk = 35° ± 10°).

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Section: Angular Diametersupporting

confidence: 86%

Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog

Korolik,

Roettenbacher,

Fischer

et al. 2023

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“…The PHASES (Palomar High-precision Astrometric Search for Exoplanet Systems) project on the PTI measured differential phase between two close-by stars, achieving ≈100-µas precision (Muterspaugh et al 2010). This concept was updated for CHARA/MIRC-X (Michigan InfraRed Combiner-eXeter) and VLTI/GRAVITY observations (see Figure 7) using precision wavelength calibration and medium spectral dispersion to overlap fringe packets, and demonstrated ≈10-20-µas differential precision sufficient to detect giant exoplanets, though none have been reported so far (Gardner et al 2022).…”

Section: Observations Of Exoplanets and Spectroscopy Of Their Atmospherementioning

confidence: 99%

Advances in Optical/Infrared Interferometry

Eisenhauer

Pfuhl

2023

Annual Review of Astronomy and Astrophysics

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After decades of fast-paced technical advances, optical/infrared (O/IR) interferometry has seen a revolution in recent years. ▪ The GRAVITY instrument at the Very Large Telescope Interferometer (VLTI) with four 8-m telescopes reaches thousand-times-fainter objects than possible with earlier interferometers, and the Center for High Angular Resolution Astronomy (CHARA) array routinely offers up to 330-m baselines and aperture-synthesis with six 1-m telescopes. ▪ The observed objects are fainter than 19 mag, the images have submilliarcsecond resolution, and the astrometry reaches microarcsecond precision. ▪ This led to breakthrough results on the Galactic Center, exoplanets, active galactic nuclei, young stellar objects, and stellar physics. Following a primer in interferometry, we summarize the advances that led to the performance boost of modern interferometers: ▪ Single-mode beam combiners now combine up to six telescopes, and image reconstruction software has advanced over earlier developments for radio interferometry. ▪ With a combination of large telescopes, adaptive optics (AO), fringe tracking, and especially dual-beam interferometry, GRAVITY has boosted the sensitivity by many orders of magnitudes. Another order-of-magnitude improvement will come from laser guide star AO. In combination with large separation fringe tracking, O/IR interferometry will then provide complete sky coverage for observations in the Galactic plane and substantial coverage for extragalactic targets. Expected final online publication date for the Annual Review of Astronomy and Astrophysics, Volume 61 is August 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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“…In many cases such identification may not be possible. For binaries sufficiently close by, follow-up observations with adaptive optics techniques may be able to resolve faint, low-mass companions in wide orbits (Gardner et al 2022). Yet even with the nondetection of a companion using state-of-the-art techniques and large-aperture telescopes, a "lighter" companion in an even smaller orbit could also account for the observed acceleration.…”

Section: Uniquely Identifying Compact Object Companionsmentioning

confidence: 99%

Weighing the Darkness. II. Astrometric Measurement of Partial Orbits with Gaia

Andrews

Breivik

Chawla

et al. 2023

ApJ

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Over the course of several years, stars trace helical trajectories as they traverse across the sky due to the combined effects of proper motion and parallax. It is well known that the gravitational pull of an unseen companion can cause deviations to these tracks. Several studies have pointed out that the astrometric mission Gaia will be able to identify a slew of new exoplanets, stellar binaries, and compact object companions with orbital periods as short as tens of days to as long as Gaia's lifetime. Here, we use mock astrometric observations to demonstrate that Gaia can identify and characterize black hole companions to luminous stars with orbital periods longer than Gaia's lifetime. Such astrometric binaries have orbital periods too long to exhibit complete orbits, and instead are identified through curvature in their characteristic helical paths. By simultaneously measuring the radius of this curvature and the orbital velocity, constraints can be placed on the underlying orbit. We quantify the precision with which Gaia can measure orbital accelerations and apply that to model predictions for the population of black holes orbiting stars in the stellar neighborhood. Although orbital degeneracies imply that many of the accelerations induced by hidden black holes could also be explained by faint low-mass stars, we discuss how the nature of certain putative black hole companions can be confirmed with high confidence using Gaia data alone.

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ARMADA. II. Further Detections of Inner Companions to Intermediate-mass Binaries with Microarcsecond Astrometry at CHARA and VLTI

Cited by 7 publications

References 58 publications

Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog

Refining the Stellar Parameters of τ Ceti: a Pole-on Solar Analog

Advances in Optical/Infrared Interferometry

Weighing the Darkness. II. Astrometric Measurement of Partial Orbits with Gaia

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