D9 (star)
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 17h 45m 40.0s[1] |
| Declination | −29° 00′ 28″[1] |
| Characteristics | |
| Evolutionary stage | Herbig Ae/Be + T Tauri |
| Astrometry | |
| Distance | 26,000 ly |
| Orbit[2] | |
| Primary | Sgr A* |
| Name | D9 |
| Period (P) | 432.62±0.01 yr |
| Semi-major axis (a) | 0.04400±0.00242 pc |
| Eccentricity (e) | 0.32±0.01 |
| Inclination (i) | 102.6±2.3° |
| Longitude of the node (Ω) | 257.25±1.61° |
| Argument of periastron (ω) (secondary) | 127.19±7.50° |
| Orbit[2] | |
| Primary | D9a |
| Name | D9b |
| Period (P) | 1.02±0.01 yr |
| Semi-major axis (a) | 1.59±0.01 AU |
| Eccentricity (e) | 0.45±0.01 |
| Inclination (i) | 75±19 or ~90° |
| Argument of periastron (ω) (secondary) | 311.75±1.65° |
| Details[2] | |
| D9a | |
| Mass | 2.8±0.5 M☉ |
| Radius | 2.00±0.13 R☉ |
| Luminosity | 72+28 −20 L☉ |
| Temperature | 11,700+1,500 −1,200 K |
| Age | 2.7+1.9 −0.3 Myr |
| D9b | |
| Mass | 0.73±0.14 M☉ |
| Age | 2.7+1.9 −0.3 Myr |
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D9 is a binary star system located in the S Cluster, a dense group of stars orbiting Sagittarius A* (Sgr A*), the supermassive black hole at the center of Milky Way Galaxy. D9 is located approximately 26,000 light-years from Earth. It is the first confirmed binary star system observed in such close proximity to a supermassive black hole, challenging existing models of star formation and stability in extreme gravitational environments.[2][3][4][5][6]
Discovery and Characteristics
[edit]The D9 system was identified by an international team led by Florian Peißker from the European Southern Observatory (ESO). The discovery utilized over 15 years of spectroscopic data collected by ESO’s Very Large Telescope (VLT) in Chile, primarily through the ERIS and SINFONI instruments. Velocity variations in the system’s infrared light confirmed its binary nature, distinguishing it from a single star.[2][4][5][7][8]
_(eso2418b).jpg)
Orbital Dynamics
[edit]The two stars in D9 are gravitationally bound, but the intense tidal forces from Sgr A* are expected to disrupt their orbit, likely causing a merger into a single star within approximately one million years. This short-lived binary phase provides a rare opportunity to study such systems in extreme conditions.[5]
Future observations using instruments like the VLT’s GRAVITY+ or the Extremely Large Telescope (ELT)'s METIS expected to further explore the system.[4][2]
References
[edit]- 1 2 Reid, M. J.; Brunthaler, A. (December 2004). "The Proper Motion of Sagittarius A*. II. The Mass of Sagittarius A*". The Astrophysical Journal. 616 (2): 872–884. arXiv:astro-ph/0408107. Bibcode:2004ApJ...616..872R. doi:10.1086/424960. ISSN 0004-637X. S2CID 16568545.
- 1 2 3 4 5 6 Peißker, Florian; Zajaček, Michal; Labadie, Lucas; Bordier, Emma; Eckart, Andreas; Melamed, Maria; Karas, Vladimír (2024). "A binary system in the S cluster close to the supermassive black hole Sagittarius A". Nature Communications. 15 (1): 10608. arXiv:2412.12727. Bibcode:2024NatCo..1510608P. doi:10.1038/s41467-024-54748-3. PMC 11652627. PMID 39690145.
- ↑ information@eso.org. "Location of binary star D9 in the Milky Way". www.eso.org. Retrieved 2025-10-21.
- 1 2 3 information@eso.org. "First ever binary star found near our galaxy's supermassive black hole". www.eso.org. Retrieved 2025-10-21.
- 1 2 3 Robert Lea (2024-12-17). "Astronomers discover 1st binary stars orbiting supermassive black hole at the center of the Milky Way". Space. Retrieved 2025-10-21.
- ↑ Hyman, Randall (2024-12-17). "Binary star system finally discovered near Milky Way center". Astronomy Magazine. Retrieved 2025-10-21.
- ↑ Koberlein, Brian (2024-12-19). "A Binary Star Found Surprisingly Close to the Milky Way's Supermassive Black Hole". Universe Today. Retrieved 2025-10-21.
- ↑ iain.todd@ourmedia.co.uk (2024-12-22). "D9 binary stars near black hole Sagittarius A*". BBC Sky at Night Magazine. Retrieved 2025-10-21.
External links
[edit]
Media related to D9 (star) at Wikimedia Commons
- Anton Petrov (15 January 2025). First Ever Binary Star Near SgrA* Black Hole Solves a Major Mystery. Video on YouTube.
