Lethe stream
The Lethe stream is a stellar stream in the Milky Way Galaxy, consisting of approximately 1100 stars. It was discovered by Carl J. Grillmair in 2008 along with the Acheron, Cocytos and Styx streams,[1] and moves with an average tangential velocity of .[2] The name of this stream stems from Lethe, the mythical river of unmindfulness in Hades.[1]
The stars in the Lethe stream are not in the plane of the Milky Way and are proposed to have originated from the debris of a globular cluster. Evidence supporting this theory of origin is taken by comparing Lethe's stars to the color magnitude diagrams (CMDs) from the Sloan Digital Sky Survey (SDSS).[1] The stream's stellar population consists of old, metal-poor stars with an approximate metallicity of . Along with it being dynamically cold and having a relatively narrow width of , these are indicators that the Lethe stream is composed of the remnants of an either extant or disrupted globular cluster instead of debris from a dwarf galaxy.[1][3]
![{\displaystyle [\mathrm {Fe/H} ]\sim -1.5}](https://wikimedia.org/api/rest_v1/media/math/render/svg/dab20aca46796aeca387c5aa3378e35406a5e2c5)
The stream was first described in 2009 by Carl Grillmair using data from the SDSS recorded at the Apache Point Observatory in New Mexico.[1]
See also
[edit]References
[edit]- 1 2 3 4 5 Grillmair, C. J. 2009, "Four New Stellar Debris Streams in the Galactic Halo" The Astrophysical Journal, 693, 1118,
- ↑ Riley, A. H., & Strigari, L. E. 2020, The Milky Way’s stellar streams and globular clusters do not align in a Vast Polar Structure Monthly Notices of the Royal Astronomical Society, 494, 983,
- ↑ Sohn, S. T., Van Der Marel, R. P., Kallivayalil, N., et al. 2016, Hubble Space Telescope Proper Motions of Individual Stars in Stellar Streams: Orphan, Sagittarius, Lethe, and the New “Parallel Stream” The Astrophysical Journal, 833, 235,