YSES 1

YSES 1

YSES 1 (TYC 8998-760-1), accompanied by two giant exoplanets, YSES 1b and YSES 1c taken by ESO SPHERE (See annotated version)
Observation data
Epoch J2000      Equinox ICRS
Constellation Musca
Right ascension 13h 25m 12.1263s
Declination −64° 56′ 20.689″
Apparent magnitude (V) 11.19
Characteristics
Evolutionary stage Pre main sequence
Spectral type K3IV
Astrometry
Radial velocity (Rv)12.84 km/s
Proper motion (μ) RA: −40.996 mas/yr
Dec.: −17.734 mas/yr
Parallax (π)10.6124±0.0116 mas
Distance307.3 ± 0.3 ly
(94.2 ± 0.1 pc)
Details
Mass1.00 M☉
Radius1.02±0.01 R☉
Luminosity10−0.34±0.01 L☉
Surface gravity (log g)4.46+0.38
−0.46 cgs
Temperature4,708+30
−33 K
Age15±3 – 27±3 Myr
Other designations
TIC 449888653, 2MASS J13251211-6456207, YSES 1
Database references
SIMBADdata

YSES 1, also known as TYC 8998-760-1, is a pre-main-sequence star located 310 light years away from Earth in the constellation of Musca, with a mass 1.00±0.02 times the Sun.

Planetary system

There are two giant substellar bodies orbiting the star. In 2020, 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.

The YSES 1 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination
(°)		 Radius
b 25.7+4.1
−3.6 or 41.6+3.6
−3.4 MJ		 146+16
−10		 — 0.44+0.17
−0.18		 90.6+1.1
−1.0		 1.58+0.06
−0.07, 1.89+0.06
−0.05 or 2.08±0.06 RJ
c 7.2±0.7 MJ 320 — — — 1.48+0.04
−0.05 RJ

YSES 1 b

YSES 1 b is the inner companion, orbiting at 146 AU (2.18×1010 km; 1.36×1010 mi) from the host star, or slightly more than 5 times the Neptune-Sun distance. Its mass was initially estimated at 14 MJ based on an age of 15 Myr and later at 21.8 MJ based on an age of 27 Myr. The planetary parameters were revised in 2026, resulting in two mass values of 25.7+4.1
−3.6 and 41.6+3.6
−3.4 MJ, depending on the age. These revised values put YSES 1 b within the brown dwarf regime. 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. 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. Observations with the James Webb Space Telescope detected silicate emission from YSES 1b, indicating the presence of a circumplanetary disk. The emission was attributed to submicron olivine dust grains. These very small and hot grains might have formed from collisions of satellites forming inside the circumplanetary disk. Observations with VLT MUSE revealed emission by hydrogen (Hα, Hβ), calcium (H+K lines) and helium, coming from YSES 1b. These lines are attributed to accretion of material from the circumplanetary disk to the surface of the planet. It is the first object in this mass range with these full combination of lines. The planet accretes between 1.11 × 10−9±0.19 MJ/yr and 1.45 × 10−9±0.19 MJ/yr (or the mass equivalent of at least 21 Lutetia per year).

YSES 1 c

YSES 1 c is a substellar object with a mass of 7.2 MJ, and orbits at 320 AU (4.8×1010 km; 3.0×1010 mi), or slightly more than 11 times the Neptune-Sun distance. Atmospheric water vapor and carbon monoxide was detected with VLT/CRIRES+. The object is of spectral class L7.5. Additionally, JWST spectra with NIRSpec and MIRI were published. The spectrum of YSES 1 c does show direct detection of silicate clouds.

References

  1. 1 2 ESO/Bohn (22 July 2020). "First ever image of a multi-planet system around a Sun-like star (uncropped, with annotations)". ESO. European Southern Observatory. Archived from the original on 24 July 2020. Retrieved 24 July 2020.
  2. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  3. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. ↑ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  5. 1 2 3 4 Bohn, Alexander (22 July 2020). "Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1". The Astrophysical Journal Letters. 898 (1): L16. arXiv:2007.10991. Bibcode:2020ApJ...898L..16B. doi:10.3847/2041-8213/aba27e. S2CID 220686536.
  6. ↑ "TYC 8998-760-1". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 July 2020.
  7. ↑ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. 1 2 3 4 5 6 7 Darcis, Michiel; Haffert, Sebastiaan Y.; Stolker, Tomas; et al. (2026-05-26). "The spectral energy distribution of YSES 1 b and its circumplanetary disc". Astronomy and Astrophysics. arXiv:2605.26805.
  9. 1 2 Bohn, A. J.; Kenworthy, M. A.; Ginski, C.; Manara, C. F.; Pecaut, M. J.; de Boer, J.; Keller, C. U.; Mamajek, E. E.; Meshkat, T.; Reggiani, M.; Todorov, K. O.; Snik, F. (January 2020). "The Young Suns Exoplanet Survey: Detection of a wide-orbit planetary-mass companion to a solar-type Sco-Cen member". Monthly Notices of the Royal Astronomical Society. 492 (1): 431–443. arXiv:1912.04284. Bibcode:2020MNRAS.492..431B. doi:10.1093/mnras/stz3462. ISSN 0035-8711.
  10. 1 2 3 4 Wood, Mackenna L.; et al. (2023). "TESS Hunt for Young and Maturing Exoplanets (THYME). IX. A 27 Myr Extended Population of Lower Centaurus Crux with a Transiting Two-planet System". The Astronomical Journal. 165 (3): 85. arXiv:2212.03266. Bibcode:2023AJ....165...85W. doi:10.3847/1538-3881/aca8fc.
  11. ↑ Wall, Mike (22 July 2020). "Multiplanet system around sunlike star photographed for 1st time ever - The two newly imaged planets are huge — 14 and 6 times more massive than Jupiter". Space.com. Retrieved 22 July 2020.
  12. 1 2 3 4 Roberts, Jonathan; Thompson, William; Wang, Jason J.; Blunt, Sarah; Balmer, William O.; Bourdarot, Guillaume; Bowler, Brendan P.; Chauvin, Gael; Eisenhauer, Frank; Henning, Thomas K.; Kammerer, Jens; Kiefer, Flavien; Kenworthy, Matthew A.; Kervella, Pierre; Lacour, Sylvestre; Lagrange, A. -M.; Nielsen, Eric L.; Pueyo, Laurent; Rickman, Emily; Sipilä, Olli; Spezzano, Silvia; Stolker, Tomas; Zurlo, Alice (2025). "New Orbital Constraints for YSES 1 b and HR 2562 B from High-Precision Astrometry and Planetary Radial Velocities". arXiv:2509.14321 [astro-ph.EP].
  13. 1 2 3 Hoch, K. K. W.; Rowland, M.; Petrus, S.; Nasedkin, E.; Ingebretsen, C.; Kammerer, J.; Perrin, M.; d'Orazi, V.; Balmer, W. O.; Barman, T.; Bonnefoy, M.; Chauvin, G.; Chen, C.; De Rosa, R. J.; Girard, J.; Gonzales, E.; Kenworthy, M.; Konopacky, Q. M.; MacIntosh, B.; Moran, S. E.; Morley, C. V.; Palma-Bifani, P.; Pueyo, L.; Ren, B.; Rickman, E.; Ruffio, J.-B.; Theissen, C. A.; Ward-Duong, K.; Zhang, Y. (2025). "Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet system". Nature. 643 (8073): 938–942. arXiv:2507.18861. Bibcode:2025Natur.643..938H. doi:10.1038/s41586-025-09174-w. PMID 40494394.
  14. ↑ Starr, Michelle (14 July 2021). "Isotopes Detected in The Atmosphere of an Exoplanet For The First Time". ScienceAlert. Retrieved 14 July 2021.
  15. ↑ Zhang, Yapeng; et al. (14 July 2021). "The 13CO-rich atmosphere of a young accreting super-Jupiter". Nature. 595 (7867): 370–372. arXiv:2107.06297. Bibcode:2021Natur.595..370Z. doi:10.1038/s41586-021-03616-x. hdl:1887/3254588. ISSN 0028-0836. PMID 34262209. S2CID 235829633.
  16. 1 2 Zhang, Yapeng; González Picos, Darío; de Regt, Sam; Snellen, Ignas A. G.; Gandhi, Siddharth; Ginski, Christian; Kesseli, Aurora Y.; Landman, Rico; Mollière, Paul; Nasedkin, Evert; Sánchez-López, Alejandro; Stolker, Tomas; Inglis, Julie; Knutson, Heather A.; Mawet, Dimitri (2024-12-01). "The ESO SupJup Survey. III. Confirmation of 13CO in YSES 1 b and Atmospheric Detection of YSES 1 c with CRIRES+". The Astronomical Journal. 168 (6): 246. arXiv:2409.16660. Bibcode:2024AJ....168..246Z. doi:10.3847/1538-3881/ad7ea9. ISSN 0004-6256.
  17. ↑ Julo, R.; Bonnefoy, M.; Chatelain, F.; Flasseur, O.; Michel, O. J. J.; Jorquera, S.; Delorme, P.; Chauvin, G. (2025). "Stellar halo subtraction alternative for accreting companions' characterization with integral field spectroscopy: Analytical and on-sky demonstration on the PDS70, HTLup, and YSES1 systems". arXiv:2509.09878 [astro-ph.IM].
  18. ↑ Hoch, Kielan; Perrin, Marshall; Ruffio, Jean-Baptiste; Theissen, Christopher; Barman, Travis; Konopacky, Quinn; Kammerer, Jens; Rickman, Emily; Balmer, William; Pueyo, Laurent; Macintosh, Bruce; Ren, Bin; Morley, Caroline; Gonzales, Eileen; Petrus, Simon (2024-04-01). "Direct Imaging Spectroscopy of Substellar Companions with JWST". AASTCS10, Extreme Solar Systems V, Bulletin of the American Astronomical Society. 56 (4): 626.13. Bibcode:2024ESS.....562613H.