Publications (42)
Imaging the warped dusty disk wind environment of SU Aurigae with MIRC-X
Aaron Labdon, Stefan Kraus, Claire L. Davies +12
SU Aurigae is a widely studied T Tauri star and here we present original state-of-the-art interferometric observations with better uv and baseline coverage than previous studies. W…
The Dynamic Inner Disk of a Planet Forming Star
Benjamin R. Setterholm, John D. Monnier, Fabien Baron +13
Planets are a natural byproduct of the stellar formation process, resulting from local aggregations of material within the disks surrounding young stars. Whereas signatures of gas-…
Three-dimensional orbit of AC Her determined: Binary-induced truncation cannot explain the large cavity in this post-AGB transition disk
Narsireddy Anugu, Jacques Kluska, Tyler Gardner +17
Some evolved binaries, namely post-asymptotic giant branch binaries, are surrounded by stable and massive circumbinary disks similar to protoplanetary disks found around young star…
Scattering and sublimation: a multi-scale view of m-sized dust in the inclined disc of HD 145718
Claire L. Davies, Evan A. Rich, Tim J. Harries +15
We present multi-instrument observations of the disc around the Herbig~Ae star, HD~145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orienta…
EXPRES. III. Revealing the Stellar Activity Radial Velocity Signature of Eridani with Photometry and Interferometry
Rachael M. Roettenbacher, Samuel H. C. Cabot, Debra A. Fischer +20
The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces of cool, main-sequence stars can mimic or overwhelm radial velocity (RV) sh…
MIRC-X: a highly-sensitive six telescope interferometric imager at the CHARA Array
Narsireddy Anugu, Jean-Baptiste Le Bouquin, John D. Monnier +11
MIRC-X (Michigan InfraRed Combiner-eXeter) is a new highly-sensitive six-telescope interferometric imager installed at the CHARA Array that provides an angular resolution equivalen…
Surprise non-detection of Upsilon Andromedae b with MIRC-X and MYSTIC at the CHARA Array
Tyler Gardner, John D. Monnier, Stefan Kraus +11
Ground-based long baseline interferometry is a powerful tool for characterizing exoplanets which are too close to their host star to be imaged with single-dish telescopes. The CHAR…
Visual Orbits of Wolf-Rayet Stars I: The Orbit of the dust-producing Wolf-Rayet binary WR\,137 measured with the CHARA Array
Noel D. Richardson, Gail H. Schaefer, Jan J. Eldridge +19
Classical Wolf-Rayet stars are the descendants of massive OB stars that have lost their hydrogen envelopes and are burning helium in their cores prior to exploding as type Ib/c sup…
Multiplicity of northern bright O-type stars with optical long baseline interferometry
Cyprien Lanthermann, Jean-Baptiste Le Bouquin, Hugues Sana +16
The study of the multiplicity of massive stars gives hints on their formation processes and their evolutionary paths, which are still not fully understood. Large separation binarie…
Precise Age For The Binary HD 21278 In The Young Alpha Persei Cluster
Christopher A. Danner, Eric L. Sandquist, Gail H. Schaefer +14
We present a study of the double-lined spectroscopic binary HD 21278 that contains one of the brightest main sequence stars in the young Persei open cluster. We analyzed new s…
Orbits and Dynamical Masses for the Active Hyades Multiple System HD 284163
Guillermo Torres, Gail H. Schaefer, Robert P. Stefanik +16
We report near-infrared long-baseline interferometric observations of the Hyades multiple system HD 284163, made with the CHARA array, as well as almost 43 yr of high-resolution sp…
High spectral-resolution interferometry down to 1 micron with Asgard/BIFROST at VLTI: Science drivers and project overview
Stefan Kraus, Daniel Mortimer, Sorabh Chhabra +10
We present science cases and instrument design considerations for the BIFROST instrument that will open the short-wavelength (Y/J/H-band), high spectral dispersion (up to R=25,000)…
Spin-orbit alignment of the Pictoris planetary system
Stefan Kraus, Jean-Baptiste LeBouquin, Alexander Kreplin +6
A crucial diagnostic that can tell us about processes involved in the formation and dynamical evolutionof planetary systems is the angle between the rotation axis of a star and a p…
The Orbits and Dynamical Masses of the Castor System
Guillermo Torres, Gail H. Schaefer, John D. Monnier +12
Castor is a system of six stars in which the two brighter objects, Castor A and B, revolve around each other every 450 yr and are both short-period spectroscopic binaries. Th…
The Small Separation A-Star Companion Population: Tentative Signatures of Enhanced Multiplicity with Primary Mass
Matthew De Furio, Tyler Gardner, John D. Monnier +6
We present updated results from our near-infrared long-baseline interferometry (LBI) survey to constrain the multiplicity properties of intermediate-mass A-type stars within 80 pc.…
Time-Evolution Images of the Hypergiant RW Cephei During the Re-brightening Phase Following the Great Dimming
Narsireddy Anugu, Douglas R. Gies, Rachael M. Roettenbacher +17
Stars with initial masses larger than 8 solar masses undergo substantial mass loss through mechanisms that remain elusive. Unraveling the origins of this mass loss is important for…
The Interferometric Binary Epsilon Cancri in Praesepe: Precise Masses and Age
Leslie M. Morales, Eric L. Sandquist, Gail H. Schaefer +16
We observe the brightest member of the Praesepe cluster, Epsilon Cancri, to precisely measure the characteristics of the stars in this binary system, en route to a new measurement…
Visual Orbits of Wolf-Rayet Stars II: The Orbit of the Nitrogen-Rich WR Binary WR 138 measured with the CHARA Array
Amanda Holdsworth, Noel Richardson, Gail H. Schaefer +19
Classical Wolf-Rayet stars are descendants of massive OB-type stars that have lost their hydrogen-rich envelopes, and are in the final stages of stellar evolution, possibly explodi…
Precision Orbit of Delphini and Prospects for Astrometric Detection of Exoplanets
Tyler Gardner, John D. Monnier, Francis C. Fekel +17
Combining visual and spectroscopic orbits of binary stars leads to a determination of the full 3D orbit, individual masses, and distance to the system. We present a full analysis o…
Pushing high angular resolution and high contrast observations on the VLTI from Y to L band with the Asgard instrumental suite: integration status and plans
Marc-Antoine Martinod, Denis Defrère, Michael J. Ireland +35
ESO's Very Large Telescope Interferometer has a history of record-breaking discoveries in astrophysics and significant advances in instrumentation. The next leap forward is its new…
Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692
Kathryn V. Lester, Gail H. Schaefer, Francis C. Fekel +18
We present the visual orbits of four spectroscopic binary stars, HD 61859, HD 89822, HD 109510, and HD 191692, using long baseline interferometry with the CHARA Array. We also obta…
Characterising the orbit and circumstellar environment of the high-mass binary MWC 166 A
Sebastian A. Zarrilli, Stefan Kraus, Alexander Kreplin +13
Context: Stellar evolution models are highly dependent on accurate mass estimates, especially for high-mass stars in the early stages of evolution. The most direct method for obtai…
Gem: a hierarchical triple system with an outer Be star
Robert Klement, Petr Hadrava, Thomas Rivinius +17
Time series of spectroscopic, speckle-interferometric, and optical long-baseline-interferometric observations confirm that Gem is a hierarchical triple system. It consists of…
ARMADA II: Further Detections of Inner Companions to Intermediate Mass Binaries with Micro-Arcsecond Astrometry at CHARA and VLTI
Tyler Gardner, John D. Monnier, Francis C. Fekel +18
We started a survey with CHARA/MIRC-X and VLTI/GRAVITY to search for low mass companions orbiting individual components of intermediate mass binary systems. With the incredible pre…
The First Dynamical Mass Determination of a Nitrogen-rich Wolf-Rayet Star using a Combined Visual and Spectroscopic Orbit
Noel D. Richardson, Laura Lee, Gail Schaefer +11
We present the first visual orbit for the nitrogen-rich Wolf-Rayet binary, WR 133 (WN5o + O9I) based on observations made with the CHARA Array and the MIRC-X combiner. This orbit r…
A triple star system with a misaligned and warped circumstellar disk shaped by disk tearing
Stefan Kraus, Alexander Kreplin, Alison K. Young +29
Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems can disrupt the disk. The…
ACCESS, LRG-BEASTS, & MOPSS: Featureless Optical Transmission Spectra of WASP-25b and WASP-124b
Chima D. McGruder, Mercedes López-Morales, James Kirk +14
We present new optical transmission spectra for two hot Jupiters: WASP-25b (M = 0.56~M; R = 1.23 R; P =~3.76 days) and WASP-124b (M = 0.58~M; R = 1.34 R; P = 3.37 d…
The Small Separation A-Star Companion Population: First Results with CHARA/MIRC-X
Matthew De Furio, Tyler Gardner, John Monnier +9
We present preliminary results from our long-baseline interferometry (LBI) survey to constrain the multiplicity properties of intermediate-mass A-type stars within 80pc. Previous m…
ARMADA I: Triple Companions Detected in B-Type Binaries alpha Del and nu Gem
Tyler Gardner, John D. Monnier, Francis C. Fekel +19
Ground-based optical long-baseline interferometry has the power to measure the orbits of close binary systems at ~10 micro-arcsecond precision. This precision makes it possible to…
Imaging the inner astronomical unit of Herbig Be star HD 190073
Nour Ibrahim, John D. Monnier, Stefan Kraus +13
Inner regions of protoplanetary disks host many complex physical processes such as star-disk interactions, magnetic fields, planet formation, and the migration of new planets. To d…
CHARA/MIRC-X -- a high-sensitive six telescope interferometric imager concept, commissioning, and early science
Narsireddy Anugu, Jean-Baptiste Le Bouquin, John D. Monnier +14
MIRC-X is a six telescope beam combiner at the CHARA array that works in J and H wavelength bands and provides an angular resolution equivalent to a =331m diameter telescope. Th…
Multiple outflows and delayed ejections revealed by early imaging of novae
Elias Aydi, John D. Monnier, Antoine Mérand +39
Novae are thermonuclear eruptions on accreting white dwarfs in interacting binaries. Although most of the accreted envelope is expelled, the mechanism -- impulsive ejection, multip…
The CHARA Array interferometric program on the multiplicity of classical Be stars: new detections and orbits of stripped subdwarf companions
Robert Klement, Thomas Rivinius, Douglas R. Gies +8
Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of Be stars owe t…
Refining the Stellar Parameters of Ceti: a Pole-on Solar Analog
Maria Korolik, Rachael M. Roettenbacher, Debra A. Fischer +16
To accurately characterize the planets a star may be hosting, stellar parameters must first be well-determined. Ceti is a nearby solar analog and often a target for exoplanet…
Establishing Oph as a Prototype Rotator: Precision Orbit with new Keck, CHARA, and RV Observations
Tyler Gardner, John D. Monnier, Francis C. Fekel +11
Alpha Ophiuchi (Rasalhague) is a nearby rapidly rotating A5IV star which has been imaged by infrared interferometry. Oph is also part of a known binary system, with a companio…
Pre-nova Observations of T CrB: A view from the CHARA Array
Ryan Norris, Narsireddy Anugu, Thomas Gaudin +38
T CrB is a symbiotic recurrent nova consisting of a red giant and white dwarf with recent eruptions in 1866 and 1946 and an anticipated eruption in the mid 2020s. We report CHARA A…
Reconstructing the mid-infrared environment in the stellar merger remnant V838 Monocerotis
Muhammad Zain Mobeen, Tomasz KamiÅski, Alexis Matter +15
V838 Mon is a stellar merger remnant that erupted in 2002 in a luminous red novae event. Although it is well studied in the optical, near infrared and submillimeter regimes, its st…
Precise Age for the Binary Star System 12 Com in the Coma Berenices Cluster
Rex Lam, Eric L. Sandquist, Gail H. Schaefer +11
We present measurements of the interferometrically-resolved binary star system 12 Com and the single giant star 31 Com in the cluster Coma Berenices. 12 Com is a double-lined spect…
Interferometric Images of the Starspot Evolution of Andromedae
Rachael M. Roettenbacher, John D. Monnier, Heidi Korhonen +21
The evolution of starspots of the giant primaries of RS CVn systems is typically detected indirectly with photometric and spectroscopic monitoring. These observations suggest slowl…
The CHARA Array Polarization Model and Prospects for Spectropolarimetry
Linling Shuai, John D. Monnier, Benjamin R. Setterholm +5
Polarimetric data provide key insights into infrared emission mechanisms in the inner disks of YSOs and the details of dust formation around AGB stars. While polarization measureme…
CHARA Near-Infrared Imaging of the Yellow Hypergiant Star Cassiopeiae: Convection Cells and Circumstellar Envelope
Narsireddy Anugu, Fabien Baron, John D. Monnier +18
Massive evolved stars such as red supergiants and hypergiants are potential progenitors of Type II supernovae, and they are known for ejecting substantial amounts of matter, up to…
The orbit and stellar masses of the archetype colliding-wind binary WR 140
Joshua D. Thomas, Noel D. Richardson, J. J. Eldridge +33
We present updated orbital elements for the Wolf-Rayet (WR) binary WR\,140 (HD\,193793; WC7pd + O5.5fc). The new orbital elements were derived using previously published measuremen…