| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 00m 13.08s [1] |
| Declination | −27° 15′ 39.1″ [1] |
| Apparent magnitude (V) | 17.462 [1] |
| Characteristics | |
| Variable type | RR Lyrae [2] |
| Astrometry | |
| Distance | 24000±2000
[3]
ly (7300±600 [3] pc) |
| Details | |
| Metallicity [Fe/H] | −1.62 ± 0.2 [3] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
MACHO 176.18833.411 (OGLE BLG-RRLYR-10353) is an RR Lyrae variable star [2] [4] located in the galactic bulge of our Milky Way Galaxy. However, it is not a galactic bulge star, it is a galactic halo star, which is on the part of its elliptical orbit that brings it within the bulge before returning to the outer parts of the galaxy, the halo. The star is currently located about 850 pc (2,800 ly) from the Galactic Center. [3] As of 2015 [update], this star has the highest velocity of any known RR Lyrae variable located in the bulge, moving at 482 km/s (1,080,000 mph), only slightly below galactic escape velocity, and 5x the average velocity of bulge stars. Its nature was discovered as part of the BRAVA-RR survey. [5]
References
- ^ a b c Soszyński, I. (2011). "The Optical Gravitational Lensing Experiment. The OGLE-III Catalog of Variable Stars. XI. RR Lyrae Stars in the Galactic Bulge". Acta Astronomica. 61 (1): 1–21. arXiv: 1105.6126. Bibcode: 2011AcA....61....1S.
- ^ a b "MACHO 176.18833.411". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 January 2017.
- ^ a b c d Andrea Kunder; et al. (22 May 2015). "A high-velocity bulge RR Lyrae variable on a halo-like orbit". The Astrophysical Journal Letters. 808 (1) (published 16 July 2015): L12. arXiv: 1506.02664. Bibcode: 2015ApJ...808L..12K. doi: 10.1088/2041-8205/808/1/L12. S2CID 55063492. L12.
- ^ "Details for MACHO 176.18833.411". VSX. AAVSO.
- ^ "Starry surprise in the bulge: encounter of a halo passerby". Space Daily. 27 July 2015.
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