Astronomers utilized the Subaru Telescope, W.M. Keck Observatory, and ESA’s Gaia mission to capture images of the brown dwarf companion orbiting the M dwarf star LSPM J1446+4633.
NIRC2 image of J1446 taken in August 2023. The white arrow indicates the location of the new companion J1446B. Image provided by: Uyama et al., doi: 10.3847/1538-3881/ae08b6.
LSPM J1446+4633 (J1446) is a nearby mid-M dwarf, situated 17 parsecs (55 light-years) away.
The newly identified brown dwarf orbits its parent star at a distance approximately 4.3 times that of the Earth from the sun, completing an orbit every 20 years.
This object, designated J1446B, has a mass ranging from 20 to 60 times that of Jupiter.
“The success of this discovery was due to the combination of three complementary observational methods: (i) radial velocity (RV) measurements via long-term infrared spectroscopic monitoring by Subaru’s IRD instrument, (ii) high-resolution near-infrared imaging with advanced adaptive optics at the W.M. Keck Observatory, and (iii) precise astronomical acceleration measurements from ESA’s Gaia mission,” stated California State University astronomer Taichi Uyama and his team.
“By integrating these datasets and applying Kepler’s laws, we were able to determine the dynamic mass and orbital parameters of J1446B with unprecedented precision.”
“Radial velocity data by itself cannot differentiate between mass and orbital inclination, but the addition of direct imaging and Gaia data resolves this ambiguity.”
“The Subaru IRD-SSP program provided crucial RV data, while Keck’s cutting-edge adaptive optics allowed for the direct detection of the companion star at very close distances from the host star.”
“Previous studies have shown that astronomical acceleration from Hipparcos and Gaia can be combined with direct imaging to detect and analyze companion objects.”
“However, Hipparcos was unable to measure faint red dwarf stars like J1446.”
“Our study is the first to apply Gaia-only acceleration data to such a system, successfully constraining the orbit and dynamical mass of a brown dwarf companion.”
Near-infrared observations of J1446B indicated a brightness variation of about 30%, hinting at dynamic atmospheric phenomena such as clouds or storms.
“This finding serves as a significant benchmark for testing brown dwarf formation theories and atmospheric models,” the astronomers noted.
“Future spectroscopic studies may enable researchers to map the weather patterns on this intriguing object.”
“This achievement highlights the efficacy of combining ground-based and space-based observatories in discovering hidden worlds beyond our solar system.”
The team’s paper was published in Astronomy Magazine.
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Taichi Uyama et al. 2025. Direct Image Exploration for Companions with Subaru/IRD Strategic Program II. A brown dwarf companion star was discovered around the nearby medium-M dwarf LSPM J1446+4633. A.J. 170, 272; doi: 10.3847/1538-3881/ae08b6
Source: www.sci.news
