UPM J1040−3551

UPM J1040-3551 is an exceptionally rare hierarchical quadruple stellar system discovered in 2025. It consists of a brighter pair of young red dwarf stars and a fainter pair of cold T-Type brown dwarfs. This configuration, a pair of brown dwarfs orbiting a pair of red dwarfs has never been observed before and serves as a benchmark for studying brown dwarfs, which are "failed stars" too massive to be planets but too small to sustain hydrogen fusion like normal stars. The system provides crucial insights into the formation and evolution of low-mass stellar and sub-stellar objects, as well as the mass distribution in the universe.^{[5][3][6][7][8][9][10][11][12][13]}

ConstellationAntlia

Right ascension10^h 40^m 55.495^s[1]

Declination−35° 51′ 31.15″^[1]

Apparentmagnitude(V)14.60±0.05^[2]

Quick facts Constellation, Right ascension ...

UPM J1040−3551

Image of UPM J1040–3551
Observation data Epoch J2000.0      Equinox ICRS
Constellation	Antlia
Right ascension	10h 40m 55.495s[1]
Declination	−35° 51′ 31.15″[1]
Apparent magnitude (V)	14.60±0.05[2]
Characteristics
Evolutionary stage	Red dwarf (Aa + Ab) + Brown dwarf (Ba + Bb)
Spectral type	M4 + M4 + T7 + T8[3]
Astrometry
Proper motion (μ)	RA: −128.580 mas/yr[1] Dec.: +10.646 mas/yr[1]
Parallax (π)	39.5518±0.0197 mas[1]
Distance	82.46 ± 0.04 ly (25.28 ± 0.01 pc)
Details[3]
Aa
Mass	0.174±0.022 M☉
Radius	0.195 R☉
Temperature	3,200 K
Metallicity [Fe/H]	−0.2±0.1 dex
Age	0.2–2.0 Gyr
Ab
Mass	0.165±0.020 M☉
Temperature	3,175 K
Metallicity [Fe/H]	−0.2±0.1 dex
Age	0.2–2.0 Gyr
Ba
Mass	0.012–0.040 M☉
Age	0.2–2.0 Gyr
Bb
Mass	0.007–0.020 M☉
Age	0.2–2.0 Gyr
Other designations
UPM J1040-3551, WISE J104055.39-355130.9, TIC 54082379, 2MASS J10405549-3551311, UCAC4 271-055289, Gaia DR3 5443160355149610368[4]
Database references
SIMBAD	data

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