109 Herculis

Star in the constellation Hercules Hercules constellation map.svg center 280 right Red circle.svg 10 109 Herculis 235 724 Location of 109 Herculis (circled in red) J2000 Hercules 18 23 41.88971 +21 46 11.1096 3.84 horizontal branch K2IIIab 1.168 0.005 −57.55 0.27 +195.971 -243.234 26.9636 0.1049 +0.87 1.05 0.18 11.93 0.06 4569 60 commas 52.4 3 2.24 −0.06 4.4 6.39 2.71 Tusizuo 109 Her +21°3411 690 169414 90139 6895 86003 J18237+2146 109+Her 109 Herculis, also named Tusizuo, is a single star in the northern constellation of Hercules. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 3.84. The star is located around 121 ly pc off distant, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −58 km/s, and may come as close as 24.85 pc ly 0 out off away in around 328,000 years. This is an aging giant star with a stellar classification of K2IIIab. It is a red clump giant, meaning it is on the horizontal branch and is generating energy through helium fusion at its core. The star is roughly six billion years old with slightly more mass than the Sun. With the supply of hydrogen at its core exhausted, it has expanded to nearly 12 times the Sun's radius. The star is radiating 52 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,569 K. Nomenclature In Chinese astronomy, 109 Herculis is one of two stars in the asterism Tú Sì (屠肆, "Butcher's Shop"). It is named Tusizuo, meaning the left star in Tusi. The IAU Working Group on Star Names approved the name Tusizuo for 109 Herculis on 17 June 2025 and it is now so entered in the IAU Catalog of Star Names. The name Tusi was already in use for the asteroid 10269 Tusi, named after a Persian astronomer. This star, together with 93 Herculis, 95 Herculis (Bodu), and 102 Herculis (Ramus), formed Cerberus, the obsolete constellation.Ian Ridpath's Star Tales - Cerberus References 109 Her 2019-06-18 XHIP: An extended hipparcos compilation Anderson E. Francis Ch. Astronomy Letters . 38 5 331 2012 2012AstL...38..331A 1108.4971 10.1134/S1063773712050015 119257644 Anugu Narsireddy Monnier John D. Mérand Antoine Flores Becky Gallenne Alexandre Gies Douglas R. Gutierrez Mayra Klement Robert Kraus Stefan Empirical H- and K-band Limb Darkening for 31 CHARA Stars: A Near-Infrared Benchmark for Stellar-Atmosphere Models 2026-07-27 The Astronomical Journal 2607.24956. Eggleton P. P. Tokovinin A. A. A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869–879 September 2008 10.1111/j.1365-2966.2008.13596.x free 2008MNRAS.389..869E 0806.2878 14878976 . Ducati J. R. VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system CDS/ADC Collection of Electronic Catalogues 2237 2002 . 2002yCat.2237....0D Mg II chromospheric radiative loss rates in cool active and quiet stars Cardini D. . Astronomy and Astrophysics 430 303–311 January 2005 10.1051/0004-6361:20041440 2005A&A...430..303C astro-ph/0409683 12136256 4529285391533766400 The Perkins catalog of revised MK types for the cooler stars Keenan Philip C. McNeil Raymond C. Astrophysical Journal Supplement Series 71 245 1989 . 1989ApJS...71..245K 10.1086/191373 Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer Baines Ellyn K. Armstrong J. Thomas Schmitt Henrique R. Zavala R. T. Benson James A. Hutter Donald J. Tycner Christopher Belle Gerard T. van 1 The Astronomical Journal 155 30 2018 1 . 1712.08109 2018AJ....155...30B 10.3847/1538-3881/aa9d8b 119427037 free Massarotti Alessandro Latham David W. Stefanik Robert P. Fogel Jeffrey Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity 1 The Astronomical Journal 135 1 209–231 January 2008 10.1088/0004-6256/135/1/209 2008AJ....135..209M . free 1 Puzeras E. Tautvaišienė G. Cohen J. G. Gray D. F. Adelman S. J. Ilyin I. Chorniy Y. High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements Monthly Notices of the Royal Astronomical Society 408 2 1225–1232 October 2010 10.1111/j.1365-2966.2010.17195.x free 1006.3857 2010MNRAS.408.1225P 44228180 . IAU Catalog of Star Names https://exopla.net/star-names/modern-iau-star-names/ 17 June 2025 Category:K-type giants Category:Horizontal-branch stars Category:Hercules (constellation) BD+21 3411 Herculis, 109 169414 090139 6895 Tusizuo