SCExAO/MEC and CHARIS Discovery of a Low-mass, 6 au Separation Companion to HIP 109427 Using Stochastic Speckle Discrimination and High-contrast Spectroscopy

Sarah Steiger, Thayne Currie, Timothy D. Brandt, Olivier Guyon, Masayuki Kuzuhara, Jeffrey Chilcote, Tyler D. Groff, Julien Lozi, Alexander B. Walter, Neelay Fruitwala, John I. Bailey,, Nicholas Zobrist, Noah Swimmer, Isabel Lipartito, Jennifer Pearl Smith, Clint Bockstiegel, Seth R. Meeker, Gregoire Coiffard, Rupert Dodkins, Paul SzyprytKristina K. Davis, Miguel Daal, Bruce Bumble, Sebastien Vievard, Ananya Sahoo, Vincent Deo, Nemanja Jovanovic, Frantz Martinache, Greg Doppmann, Motohide Tamura, N. Jeremy Kasdin, Benjamin A. Mazin

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24 Scopus citations


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 Microwave Kinetic Inductance Detector Exoplanet Camera (MEC) and CHARIS integral field spectrograph. CHARIS data reduced with reference star point spread function (PSF) subtraction yield 1.1-2.4 μm 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 p photometry from Keck/NIRC2, the SCExAO data favors a spectral type, effective temperature, and luminosity of M4-M5.5, 3000-3200 K, and, 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+3.0-0.48 au, an eccentricity of M o˙. This work shows the potential for extreme AO systems to utilize speckle statistics in addition to widely used postprocessing methods to directly image faint companions to nearby stars near the telescope diffraction limit.

Original languageEnglish (US)
Article number44
JournalAstronomical Journal
Issue number2
StatePublished - Aug 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • Near-IR spectrum of HIP 109427 with SCExAO/CHARIS

    Steiger, S. (Creator), Currie, T. (Creator), Brandt, T. D. (Creator), Guyon, O. (Creator), Kuzuhara, M. (Creator), Chilcote, J. (Creator), Groff, T. D. (Creator), Lozi, J. (Creator), Walter, A. B. (Creator), Fruitwala, N. (Creator), Zobrist, N. (Creator), Swimmer, N. (Creator), Lipartito, I. (Creator), Smith, J. P. (Creator), Bockstiegel, C. (Creator), Meeker, S. R. (Creator), Coiffard, G. (Creator), Dodkins, R. (Creator), Szypryt, P. (Creator), Davis, K. K. (Creator), Daal, M. (Creator), Bumble, B. (Creator), Vievard, S. (Creator), Sahoo, A. (Creator), Deo, V. (Creator), Jovanovic, N. (Creator), Martinache, F. (Creator), Doppmann, G. (Creator), Tamura, M. (Creator), Kasdin, N. J. (Creator), Mazin, B. A. (Creator), Guyon, O. (Creator), Bailey III, J. I. (Contributor) & Tamura, M. (Creator), Centre de Donnees Strasbourg (CDS), 2021


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