YSES 1

YSES 1, also known as TYC 8998-760-1, is a young star, about 27 Myr old, located 310 light years away in the constellation of Musca, with a mass 1.00±0.02 times the Sun.

YSES 1

TYC 8998-760-1, accompanied by two giant exoplanets, TYC 8998-760-1b and TYC 8998-760-1c[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Musca
Right ascension	13h 25m 12.1263s[2]
Declination	−64° 56′ 20.689″[2]
Apparent magnitude (V)	11.19[3]
Characteristics
Evolutionary stage	Pre-main sequence[4]
Spectral type	K3IV[5]
Astrometry
Radial velocity (Rv)	12.84[6] km/s
Proper motion (μ)	RA: −40.996[2] mas/yr Dec.: −17.734[2] mas/yr
Parallax (π)	10.6124±0.0116 mas[2]
Distance	307.3 ± 0.3 ly (94.2 ± 0.1 pc)
Details
Mass	1.00[4] M☉
Radius	1.01[2] R☉
Luminosity	0.508[2] L☉
Surface gravity (log g)	4.4[2] cgs
Temperature	4,862[2] K
Age	27[7] Myr
Other designations
TIC 449888653, 2MASS J13251211-6456207, YSES 1
Database references
SIMBAD	data

Planetary system

There are two giant bodies orbiting the star. The European Southern Observatory's Very Large Telescope photographed the two bodies using its SPHERE instrument, producing the first direct image of multiple bodies orbiting a Sun-like star.^[1][8]

The YSES 1 planetary system^[7][4][9]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (years)	Eccentricity	Inclination	Radius
b	21.8±3 MJ	162	4,500	0 (assumed)	—	3.0+0.2 −0.7 RJ
c	7.2±0.7 MJ	320	5,700	0 (assumed)	—	1.1+0.6 −0.3 RJ

TYC 8998-760-1 b

TYC 8998-760-1 b is a body which has a mass 21.8 times that of Jupiter (most likely making it a brown dwarf), and a radius of 3 R_J. It orbits at a distance of 162 AU (2.42×10¹⁰ km; 1.51×10¹⁰ mi), or slightly more than 5 times the Neptune-Sun distance.^[4][10][7] In July 2021, astronomers reported the detection, for the first time, of an isotope in the atmosphere of an exoplanet; more specifically, the isotope Carbon-13 (C¹³) was found in the atmosphere.^[11][12] This was later confirmed with VLT/CRIRES⁺. This spectrum showed that the atmosphere is dominated by water vapor and carbon monoxide. The researchers also detect hydrogen fluoride in the atmosphere. The object is an L-dwarf with a spectral type of L0.^[13]

TYC 8998-760-1 c

TYC 8998-760-1 c is a body with a mass of 7.2 M_J, and orbits at 320 AU (4.8×10¹⁰ km; 3.0×10¹⁰ mi), or slightly more than 11 times the Neptune-Sun distance.^[4][7] Atmospheric water vapor and carbon monoxide was detected with VLT/CRIRES⁺. The object is an L-dwarf with a spectral type of L7.5.^[13] Additionally JWST spectra with NIRSpec and MIRI will be published in the future. The spectrum of TYC 8998-760-1 c does show direct detection of silicate clouds.^[14]