TVLM 513-46546

TVLM 513-46546 is an M9 ultracool dwarf at the red dwarf/brown dwarf mass boundary in the constellation Boötes. It exhibits flare star activity, which is most pronounced at radio wavelengths. The star has a mass approximately 80 times the mass of Jupiter (or 8 percent of the Sun's mass). The radio emission is broadband and highly circularly polarized, similar to planetary auroral radio emissions.^[9] The radio emission is periodic, with bursts emitted every 7054 s, with nearly one hundredth of a second precision. Subtle variations in the radio pulses could suggest that the ultracool dwarf rotates faster at the equator than the poles (differential rotation) in a manner similar to the Sun.^[10]

TVLM 513-46546

TVLM 513-46546 (the red dot in the center), as seen by the Sloan Digital Sky Survey.
Observation data Epoch J2000      Equinox J2000
Constellation	Boötes[1]
Right ascension	15h 01m 08.18646s[2]
Declination	+22° 50′ 02.1379″[2]
Apparent magnitude (V)	15.09[3]
Characteristics
Evolutionary stage	Brown dwarf[4]
Spectral type	M9[5]
Astrometry
Proper motion (μ)	RA: −43.120±0.111 mas/yr[2] Dec.: −65.138±0.140 mas/yr[2]
Parallax (π)	93.1655±0.1355 mas[2]
Distance	35.01 ± 0.05 ly (10.73 ± 0.02 pc)
Details
Mass	0.06–0.08[4][6] M☉
Radius	0.097 – 0.109[6] R☉
Luminosity	0.00026[6] L☉
Temperature	2242±55[7] K
Rotation	1.96 h[6]
Rotational velocity (v sin i)	60[6] km/s
Age	>400[6][5] Myr
Other designations
2MASS J15010818+2250020, 2MASSI J1501081+225001, 2MUCD 20596
Database references
SIMBAD	data

Near-infrared light curves for TVLM 513–46546, adapted from Harding et al. (2013)^[8]

Planetary system

On 4 August 2020 astronomers announced the discovery of a Saturn-like planet TVLM 513b around this star with a period of 221±5 days, a mass of between 0.35 and 0.42 M_J, a circular orbit (e≃0), a semi-major axis of between 0.28 and 0.31 AU and an inclination angle of 71−88°. The companion was detected by the radio astrometry method.^[5]

The TVLM 513-46546 planetary system

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.35−0.42 MJ	0.28−0.31	221±5	0	71−88°	—