DISCOVERY OF A FAINT COMPANION TO ALCOR USING MMT/AO 5 μm IMAGING

@article{Mamajek2010DISCOVERYOA,
  title={DISCOVERY OF A FAINT COMPANION TO ALCOR USING MMT/AO 5 $\mu$m IMAGING},
  author={Eric E. Mamajek and Matthew A. Kenworthy and Philip M. Hinz and Michael R. Meyer},
  journal={The Astronomical Journal},
  year={2010},
  volume={139},
  pages={919 - 925}
}
We report the detection of a faint stellar companion to the famous nearby A5V star Alcor (80 UMa). The companion has M-band (λ = 4.8 μm) magnitude 8.8 and projected separation 1.″11 (28 AU) from Alcor. The companion is most likely a low-mass (∼0.3 M☉) active star which is responsible for Alcor's X-ray emission detected by ROSAT (LX ≃ 1028.3 erg s−1). Alcor is a nuclear member of the Ursa Major star cluster (UMa; d ≃ 25 pc, age ≃ 0.5 Gyr), and has been occasionally mentioned as a possible… 

Figures and Tables from this paper

The Volume-limited A-Star (VAST) survey – I. Companions and the unexpected X-ray detection of B6–A7 stars
With an adaptive optics imaging survey of 148 B6―A7 stars, we have tested the hypothesis that unresolved lower mass companions are the source of the unexpected X-ray detections of stars in this
Evidence for the nearby F4V star λ Ara as a binary system
We report on the spectroscopic evidence for the nearby, bright and supposedly single F4V star λ Ara as a binary system. The basic observational tracer is a discrepancy with the Hipparcos-based
The Ages of A-Stars I: Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group
We have observed and spatially resolved a set of seven A-type stars in the nearby Ursa Major moving group with the Classic, CLIMB, and PAVO beam combiners on the Center for High Angular Resolution
The LEECH Exoplanet Imaging Survey: Orbit and Component Masses of the Intermediate Age, Late-Type Binary NO UMa
We present high-resolution Large Binocular Telescope LBTI/LMIRcam images of the spectroscopic and astrometric binary NO UMa obtained as part of the LBT Interferometer Exozodi Exoplanet Common Hunt
Stellar multiplicity and debris discs: an unbiased sample
Circumstellar dust disks have been observed around many nearby stars. However, many stars are part of binary or multiple stellar systems. A natural question arises regarding the presence and
A Pre-Gaia Census of Nearby Stellar Groups
  • E. Mamajek
  • Physics, Geology
    Proceedings of the International Astronomical Union
  • 2015
Abstract The nearest, youngest groups of stars to the Sun provide important samples of age-dated stars for studying circumstellar disk evolution, imaged exoplanets, and brown dwarfs. I briefly
The discrepancy between dynamical and theoretical mass in the triplet-system 2MASS J10364483+1521394
We combine new Lucky Imaging astrometry from NTT/AstraLux Sur with already published astrometry from the AstraLux Large M-dwarf Multiplicity Survey to compute orbital elements and individual masses
BAYESIAN AGES FOR EARLY-TYPE STARS FROM ISOCHRONES INCLUDING ROTATION, AND A POSSIBLE OLD AGE FOR THE HYADES
We combine recently computed models of stellar evolution using a new treatment of rotation with a Bayesian statistical framework to constrain the ages and other properties of early-type stars. We
Application of a Damped Locally Optimized Combination of Images Method to the Spectral Characterization of Faint Companions Using an Integral Field Spectrograph
High-contrast imaging instruments are now being equipped with integral field spectrographs (IFSs) to facilitate the detection and characterization of faint substellar companions. Algorithms currently
TESS Hunt for Young and Maturing Exoplanets (THYME). III. A Two-planet System in the 400 Myr Ursa Major Group
Exoplanets can evolve significantly between birth and maturity, as their atmospheres, orbits, and structures are shaped by their environment. Young planets (<1 Gyr) offer an opportunity to probe the
...
...

References

SHOWING 1-10 OF 59 REFERENCES
PARALLACTIC MOTION FOR COMPANION DISCOVERY: AN M-DWARF ORBITING ALCOR
The A5V star Alcor has an M3–M4 dwarf companion, as evidenced by a novel astrometric technique. Imaging spectroscopy combined with adaptive optics coronagraphy allowed for the detection and
MMT/AO 5 μm IMAGING CONSTRAINTS ON THE EXISTENCE OF GIANT PLANETS ORBITING FOMALHAUT AT ∼13–40 AU
A candidate ≲3 MJup extrasolar planet was recently imaged by Kalas et al. using Hubble Space Telescope/Advanced Camera for Surveys and Keck II at 12.″7 (96 AU) separation from the nearby (d = 7.7 pc)
Deep L′- and M-band Imaging for Planets around Vega and ϵ Eridani
We have obtained deep adaptive optics (AO) images of Vega and ϵ Eri to search for planetary mass companions. We observed at the MMT in the L′ (3.8 μm) and M (4.8 μm) bands using Clio, a recently
Thermal Infrared Constraint to a Planetary Companion of Vega with the MMT Adaptive Optics System
Vega may have a massive companion in a wide orbit, as evidenced by structure in its cold dust debris. We have tested this hypothesis by direct imaging with adaptive optics in the M band. The
THE X-RAY EMISSION OF A-TYPE STARS
From X-ray images in the ROSAT public archives, we determine soft X-ray fluxes, or flux upper limits, for 74 A-type stars, which have been observed during deep integrations with the PSPC. Nine
High-Precision Near-Infrared Photometry of a Large Sample of Bright Stars Visible from the Northern Hemisphere
We present the results of 8 yr of infrared photometric monitoring of a large sample of stars visible from Teide Observatory (Tenerife, Canary Islands). The final archive is made up of 10,949
Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group
Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca II H and K emission measurements, literature-based abundance estimates, and updated photometry
A catalogue of multiplicity among bright stellar systems
We consider the multiplicity of stellar systems with (combined) magnitude brighter than 6.00 in Hipparcos magnitudes. We identify 4559 such bright systems (including the Sun), and the frequencies of
CCD astrometry and components instrumental magnitude difference of 432 Hipparcos wide visual double stars
Context. We measured the angular separations, position angles, $\Delta V$, $\Delta y$ and $\Delta I$ of wide visual double stars during the period 2003–2005. At least one component of the double
Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system
The Pulkovo Compilation of Radial Velocities (PCRV) has been made to study the stellar kinematics in the local spiral arm. The PCRV contains weighted mean absolute radial velocities for 35 495
...
...