SCExAO/MEC and CHARIS Discovery of a Low Mass, 6 AU-Separation Companion to HIP 109427 using Stochastic Speckle Discrimination and High-Contrast Spectroscopy

Abstract

We report the direct imaging discovery of a low-mass companion to the nearby accelerating A star, HIP 109427, with the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument coupled with the MKID Exoplanet Camera (MEC) and CHARIS integral field spectrograph. CHARIS data reduced with reference star PSF subtraction yield 1.1-2.4 $\mu$m spectra. MEC reveals the companion in $Y$ and $J$ band at a comparable signal-to-noise ratio using stochastic speckle discrimination, with no PSF subtraction techniques. Combined with complementary follow-up $L_{\mathrm{p}}$ photometry from Keck/NIRC2, the SCExAO data favors a spectral type, effective temperature, and luminosity of M4-M5.5, 3000-3200 $K$, and ${\log }_{10}(L/L_{\odot })=-2.28_{-0.04}^{+0.04}$, respectively. Relative astrometry of HIP 109427 B from SCExAO/CHARIS and Keck/NIRC2, and complementary Gaia-Hipparcos absolute astrometry of the primary favor a semimajor axis of $6.55_{-0.48}^{+3.0}$ au, an eccentricity of $0.54_{-0.15}^{+0.28}$, an inclination of $66.7_{-14}^{+8.5}$ degrees, and a dynamical mass of $0.280_{-0.059}^{+0.18}$ $M_{\odot }$. This work shows the potential for extreme AO systems to utilize speckle statistics in addition to widely-used post-processing methods to directly image faint companions to nearby stars near the telescope diffraction limit.

13 pages, 7 figures, 3 tables

References in corpus (20)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The Gemini Planet Imager: First Light
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• Fundamental limitations of high contrast imaging set by small sample statistics
• Discovery of a warm, dusty giant planet around HIP65426
• M dwarfs: effective temperatures, radii and metallicities
• The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets
• Speckle noise and dynamic range in coronagraphic images
• Extrasolar planets and brown dwarfs around A-F type stars VI. High precision RV survey of early type dwarfs with HARPS
• No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals
• Confidence Level and Sensitivity Limits in High Contrast Imaging
• Reference star differential imaging of close-in companions and circumstellar disks with the NIRC2 vortex coronagraph at W.M. Keck Observatory
• The W. M. Keck Observatory infrared vortex coronagraph and a first image of HIP79124 B
• Large-format platinum silicide microwave kinetic inductance detectors for optical to near-IR astronomy
• The MKID Exoplanet Camera for Subaru SCExAO
• SCExAO/CHARIS Direct Imaging Discovery of a 20 au Separation, Low-Mass Ratio Brown Dwarf Companion to an Accelerating Sun-like Star
• Second Generation Readout For Large Format Photon Counting Microwave Kinetic Inductance Detectors
• Detection of faint companions through stochastic speckle discrimination
• Gemini Planet Imager Observational Calibrations XIV: Polarimetric Contrasts and New Data Reduction Techniques

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