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

Steiger, Sarah and Currie, Thayne and Brandt, Timothy D. and Guyon, Olivier and Kuzuhara, Masayuki and Chilcote, Jeffrey and Groff, Tyler D. and Lozi, Julien and Walter, Alexander B. and Fruitwala, Neelay and Bailey, III, John I. and Zobrist, Nicholas and Swimmer, Noah and Lipartito, Isabel and Smith, Jennifer Pearl and Bockstiegel, Clint and Meeker, Seth R. and Coiffard, Gregoire and Dodkins, Rupert and Szypryt, Paul and Davis, Kristina K. and Daal, Miguel and Bumble, Bruce and Vievard, Sebastien and Sahoo, Ananya and Deo, Vincent and Jovanovic, Nemanja and Martinache, Frantz and Doppmann, Greg and Tamura, Motohide and Kasdin, N. Jeremy and Mazin, Benjamin A. (2021) SCExAO/MEC and CHARIS Discovery of a Low-mass, 6 au Separation Companion to HIP 109427 Using Stochastic Speckle Discrimination and High-contrast Spectroscopy. Astronomical Journal, 162 (2). Art. No. 44. ISSN 0004-6256. doi:10.3847/1538-3881/ac02cc.

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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 Lp photometry from Keck/NIRC2, the SCExAO data favors a spectral type, effective temperature, and luminosity of M4–M5.5, 3000–3200 K, and log₁₀(L/L_⊙)= -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^(+3.0)_(−0.48) 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_⊙. 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.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Steiger, Sarah0000-0002-4787-3285
Currie, Thayne0000-0002-7405-3119
Brandt, Timothy D.0000-0003-2630-8073
Guyon, Olivier0000-0002-1097-9908
Kuzuhara, Masayuki0000-0002-4677-9182
Chilcote, Jeffrey0000-0001-6305-7272
Groff, Tyler D.0000-0001-5978-3247
Lozi, Julien0000-0002-3047-1845
Fruitwala, Neelay0000-0003-3900-4079
Bailey, III, John I.0000-0002-4272-263X
Zobrist, Nicholas0000-0003-3146-7263
Swimmer, Noah0000-0001-5721-8973
Lipartito, Isabel0000-0003-4792-6479
Smith, Jennifer Pearl0000-0002-0849-5867
Dodkins, Rupert0000-0002-3973-7646
Davis, Kristina K.0000-0001-5587-845X
Daal, Miguel0000-0002-1134-2116
Vievard, Sebastien0000-0003-4018-2569
Sahoo, Ananya0000-0003-2806-1254
Deo, Vincent0000-0003-4514-7906
Jovanovic, Nemanja0000-0001-5213-6207
Martinache, Frantz0000-0003-1180-4138
Tamura, Motohide0000-0002-6510-0681
Kasdin, N. Jeremy0000-0002-6963-7486
Mazin, Benjamin A.0000-0003-0526-1114
Alternate Title:SCExAO/MEC and CHARIS Discovery of a Low Mass, 6 AU-Separation Companion to HIP 109427 using Stochastic Speckle Discrimination and High-Contrast Spectroscopy
Additional Information:© 2021. The American Astronomical Society. Received 2021 March 2; revised 2021 April 16; accepted 2021 May 17; published 2021 July 6. S.S. and N.F. are supported by a grant from the Heising-Simons Foundation. K.K.D. is supported by the NSF Astronomy and Astrophysics Postdoctoral Fellowship program under award # 1801983. J.P.S. and N.Z. are both supported by a NASA Space Technology Research Fellowship. I.L. is supported by the National Science Foundation Graduate Research Fellowship under grant # 1650114. T.C. was supported by a NASA Senior Postdoctoral Fellowship and NASA/Keck grant LK-2663-948181. M.T. is supported by JSPS KAKENHI grant # 18H05442, # 15H02063, and # 22000005. We thank the Subaru and NASA Keck Time Allocation Committees for their generous support of this program and Chas Beichman and Dawn Gelino for graciously supporting additional NIRC2 time. This work makes use of the Keck Observatory Archive (KOA), a joint development between the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI). CHARIS was built at Princeton University under a Grant-in-Aid for Scientific Research on Innovative Areas from MEXT of the Japanese government (# 23103002). The development of SCExAO was supported by the Japan Society for the Promotion of Science (Grant-in-Aid for Research #23340051, #26220704, #23103002, #19H00703, and #19H00695), the Astrobiology Center of the National Institutes of Natural Sciences, Japan, the Mt Cuba Foundation and the director's contingency fund at Subaru Telescope. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community, and are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Heising-Simons FoundationUNSPECIFIED
NSF Astronomy and Astrophysics FellowshipAST-1801983
NASA Space Technology Research FellowshipUNSPECIFIED
NSF Graduate Research FellowshipDGE-1650114
NASA Postdoctoral ProgramUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)18H05442
Japan Society for the Promotion of Science (JSPS)15H02063
Japan Society for the Promotion of Science (JSPS)22000005
Japan Society for the Promotion of Science (JSPS)23103002
Japan Society for the Promotion of Science (JSPS)23340051
Japan Society for the Promotion of Science (JSPS)26220704
Japan Society for the Promotion of Science (JSPS)19H00703
Japan Society for the Promotion of Science (JSPS)19H00695
National Institutes of Natural Sciences of JapanUNSPECIFIED
Mt. Cuba FoundationUNSPECIFIED
Subaru TelescopeUNSPECIFIED
Subject Keywords:Direct imaging; Astronomy data analysis; Exoplanet detection methods; Low mass stars
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Direct imaging (387); Astronomy data analysis (1858); Exoplanet detection methods (489); Low mass stars (2050)
Record Number:CaltechAUTHORS:20210709-222308692
Persistent URL:
Official Citation:Sarah Steiger et al 2021 AJ 162 44
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109768
Deposited By: George Porter
Deposited On:09 Jul 2021 23:17
Last Modified:16 Nov 2021 19:37

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