Tyler Gardner
A5070054019- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Poetry Analysis and Criticism
- Library Science and Administration
- Semantic Web and Ontologies
- Digital Humanities and Scholarship
- Library Collection Development and Digital Resources
- Gamma-ray bursts and supernovae
- Digital Games and Media
- Web and Library Services
- Library Science and Information Systems
- Astrophysical Phenomena and Observations
- Comics and Graphic Narratives
- Pulsars and Gravitational Waves Research
- American Sports and Literature
- Space Exploration and Technology
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Astronomical and nuclear sciences
- Service-Oriented Architecture and Web Services
- Big Data and Business Intelligence
University of Exeter
2022-2024
University of Michigan
2018-2023
Michigan United
2020-2023
Ann Arbor Center for Independent Living
2023
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2020
South University
2020
Université Paris Cité
2020
Observatoire de Paris
2020
Centre National de la Recherche Scientifique
2020
Sorbonne Université
2020
We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. obtained spectra and 100 $\mu$as precision astrometry both b c in two epochs, as well spatially resolving hot inner disk around star. Rejecting unstable orbits, we found a nonzero eccentricity for $0.17 \pm 0.06$, near-circular orbit c, an orbital configuration that is consistent planets migrating into 2:1 mean motion resonance. Enforcing dynamical stability, 95% upper...
Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive planets with a small orbital period, whereas direct detection is orbiting at large distance from their host star. %, thus on long period. This dichotomy makes it difficult combine the techniques single target once. Simultaneous measurements made by offer possibility of determining mass luminosity method testing formation models. Here, we aim show how...
Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems disrupt the disk. Theoretical models predict that if is misaligned with orbital plane stars, should warp break into precessing rings, phenomenon known as tearing. We present observations triple system GWOrionis, finding evidence for Our images show an eccentric ring planes outer The casts shadows on strongly warped intermediate region If...
Abstract Michigan InfraRed Combiner-eXeter (MIRC-X) is a new highly sensitive six-telescope interferometric imager installed at the CHARA Array that provides an angular resolution equivalent of up to 330 m diameter baseline telescope in J - and H -band wavelengths ( <?CDATA $\tfrac{\lambda }{2B}\sim 0.6$?> mas). We upgraded original Combiner (MIRC) instrument improve sensitivity wavelength coverage two phases. First, revolutionary sub-electron noise fast-frame-rate C-RED ONE camera based on...
Abstract Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of owe their rapid mass angular momentum transfer in a binary. The faint, stripped companions can be helium-burning subdwarf OB-type (sdOBs), white dwarfs (WDs), or neutron stars. We present optical/near-infrared Center for High Angular Resolution Astronomy (CHARA) interferometry 37 selected spectroscopic indications...
The Gl 486 system consists of a very nearby, relatively bright, weakly active M3.5 V star at just 8 pc with warm transiting rocky planet about 1.3 R_Terra and 3.0 M_Terra that is ideal for both transmission emission spectroscopy testing interior models telluric planets. To prepare future studies, we collected light curves seven new transits observed the CHEOPS space mission radial velocities obtained MAROON-X/Gemini North CARMENES/Calar Alto telescopes, together previously published...
The Michigan Young Star Imager at CHARA (MYSTIC) is a K-band interferometric beam combining instrument funded by the U.S. National Science Foundation, designed primarily for imaging sub-au scale disk structures around nearby young stars and to probe planet formation process.Installed Array in July 2021, with baselines up 331 m, MYSTIC provides maximum angular resolution of λ∕2B ∼ 0.7 mas.The injects phase-corrected light from array into inexpensive, single-mode, polarization maintaining...
ABSTRACT We present updated orbital elements for the Wolf–Rayet (WR) binary WR 140 (HD 193793; WC7pd + O5.5fc). The new were derived using previously published measurements along with 160 radial velocity across 2016 periastron passage of 140. Additionally, four astrometry collected CHARA Array. With these measurements, we derive stellar masses $M_{\rm WR} = 10.31\pm 0.45 \, \mathrm{M}_\odot$ and O} 29.27\pm 1.14 \mathrm{M}_{\odot }$. also include a discussion evolutionary history this system...
Classical Be stars are possible products of close binary evolution, in which the mass donor becomes a hot, stripped O or B-type subdwarf (sdO/sdB), and gainer spins up grows disk to become star. While several Be+sdO binaries have been identified, dynamical masses other fundamental parameters available only for single system, limiting confrontation with evolution models. In this work, we present direct interferometric detections sdO companions three 28 Cyg, V2119 60 all were previously found...
European Southern Observatory (ESO)'s Very Large Telescope Interferometer (VLTI), Paranal, Chile, is one of the most proficient observatories in world for high angular resolution astronomy. It has hosted several interferometric instruments operating various bandwidths infrared. As a result, VLTI yielded countless discoveries and technological breakthroughs. We propose to ESO new concept visitor instrument VLTI: Asgard. an instrumental suite comprised four natively collaborating instruments:...
Abstract Stars with initial masses larger than 8 M ⊙ undergo substantial mass loss through mechanisms that remain elusive. Unraveling the origins of this is important for comprehending evolutionary path these stars, type supernova explosion, and whether they become neutron stars or black hole remnants. In 2022 December, RW Cep experienced Great Dimming in its visible brightness, presenting a unique opportunity to understand mass-loss mechanisms. Our previous observations from CHARA Array,...
Abstract On 2019 August 14 the Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo gravitational wave interferometer announced detection of a binary merger, S190814bv, with low false alarm rate about 1 in 1.6 × 10 25 yr, distance 267 ± 52 Mpc, 90% (50%) localization region 23 (5) deg 2 , probability being neutron star–black hole (NS–BH) merger >99%. The LIGO/Virgo Collaboration (LVC) defines NS–BH such that lighter member has mass <3 M ⊙ more massive one >5 this...
Abstract To accurately characterize the planets a star may be hosting, stellar parameters must first well determined. τ Ceti is nearby solar analog and often target for exoplanet searches. Uncertainties in observed rotational velocities have made constraining Ceti’s inclination difficult. For planet candidates from radial velocity (RV) observations, this leads to substantial uncertainties planetary masses, as only minimum mass ( <?CDATA $m\sin i$?> <mml:math...
Abstract The inner regions of protoplanetary disks host many complex physical processes such as star–disk interactions, magnetic fields, planet formation, and the migration new planets. To study directly this region requires milliarcsecond angular resolution, beyond diffraction limit world's largest optical telescopes even too small for millimeter-wave interferometer Atacama Large Millimeter/submillimeter Array (ALMA). However, we can use infrared interferometers to image astronomical unit....
Many classical Be stars acquire their very rapid rotation by mass- and angular-momentum transfer in massive binaries, marking the first phase of evolutionary chain. Later-stage products such as Be+subdwarf- Be+neutron-star binaries (Be X-ray binaries), are also well known, although search for definitive proof Be+white dwarf companions is ongoing. Short-lived intermediate-phase objects, that is, past interaction stage but with a donor star has not yet reached end its evolution or contraction,...
Abstract Because many classical Be stars may owe their nature to mass and angular-momentum transfer in a close binary, the present masses, temperatures, radii of components are high interest for comparison stellar evolution models. Object κ Dra is 61.5 day single-lined binary with B6 IIIe primary. With CHARA Array instruments MIRC/MIRC-X MYSTIC, we detected secondary at (approximately photospheric) flux ratios 1.49% ± 0.10% 1.63% 0.09% H K band, respectively. From large diverse optical...
Context . Dual-field interferometric observations with VLTI/GRAVITY sometimes require the use of a binary calibrator. This is star whose individual components remain unresolved by interferometer, separation between 400 and 2000 mas for Unit Telescopes (UTs), or 1200–3000 Auxiliary (ATs). The vector also needs to be predictable within 10 proper pointing instrument. Aims No list properly vetted calibrators was available so far dual-field on UTs. Our objective compile such make it community....
Abstract Planets are a natural byproduct of the stellar formation process, resulting from local aggregations material within disks surrounding young stars. Whereas signatures gas-giant planets at large orbital separations have been observed and successfully modeled protoplanetary disks, pathways their host star’s future habitable zones remain poorly understood. Analyzing multiple nights observations conducted over short, 2 month span with MIRC-X PIONIER instruments CHARA Array VLTI,...
The cool hypergiant star RW Cephei is currently in a deep photometric minimum that began several years ago. This event bears strong similarity to the Great Dimming of red supergiant Betelgeuse occurred 2019-2020. We present first resolved images we obtained with CHARA Array interferometer. angular diameter and Gaia distance estimates indicate stellar radius 900 - 1760 R_sun which makes Cep one largest stars known Milky Way. reconstructed, near-infrared show striking asymmetry disk...
The study of the multiplicity massive stars gives hints on their formation processes and evolutionary paths, which are still not fully understood. Large separation binaries (>50 milliseconds arc, mas) can be probed by adaptive-optics-assisted direct imaging sparse aperture masking, while close resolved photometry spectroscopy. However, optical long baseline interferometry is mandatory to establish Galactic at gap between 1 50 mas. In this paper, we aim demonstrate capability new...
Abstract We present results for the inflated super-Neptune HATS-8b from Michigan Optical Planetary Spectra Survey (MOPSS). This program is aimed at creating a database of optical planetary transmission spectra all observed, reduced, and analyzed with uniform method benefit enabling comparative exoplanet studies. orbits G dwarf low-density radius 0.873 R Jup , mass 0.138 M density 0.259 g cm −3 . Two transits were observed in 2017 July August Inamori-Magellan Areal Camera Spectrograph (IMACS)...
Context. FU Orionis is the archetypal FUor star, a subclass of young stellar object (YSO) that undergo rapid brightening events, often gaining 4-6 magnitudes on timescales days. This associated with massive increase in accretion; one most ubiquitous processes astrophysics from planets and stars to super-massive black holes. We present multi-band interferometric observations Ori circumstellar environment, including first J-band YSO. Aims. investigate morphology temperature gradient inner-most...
Time series of spectroscopic, speckle-interferometric, and optical long-baseline-interferometric observations confirm that $\nu$ Gem is a hierarchical triple system. It consists an inner binary composed two B-type stars outer classical Be star. Several photospheric spectral lines the components were disentangled, revealing with very different rotational broadening ($\sim$260 $\sim$140 kms$^{-1}$, respectively), while star remain undetected. From combined spectroscopic astrometric orbital...
The distortions of absorption line profiles caused by photospheric brightness variations on the surfaces cool, main-sequence stars can mimic or overwhelm radial velocity (RV) shifts due to presence exoplanets. latest generation precision RV spectrographs aims detect amplitudes $\lesssim 10$ cm s$^{-1}$, but requires mitigation stellar signals. Statistical techniques are being developed differentiate between Keplerian and activity-related perturbations. Two important challenges, however,...
Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how combination data obtained by Gaia GRAVITY can help enlarge sample substellar companions with measured dynamical masses. We show Non-Single-Star (NSS) two-body orbit catalogue contained in DR3 be used to inform high-angular-resolution follow-up observations GRAVITY. Applying method presented this work eight candidate systems, detect all predicted companions, seven which were...