|Distance (comoving)||22.6 million parsec|
Equinox J2000.0]] (ICRS)
|Right ascension||22h 28.1m|
|Evolutionary stage||Luminous blue variable?|
|Radial velocity (Rv)||(of galaxy) 1,606 km/s|
|PHL 293 (Simbad mistakenly showing results for PHL 293B)|
It had a very likely associated, notable, blue-light, long-lived star with constant outbursts or a large supernova observed to have faded and which then disappeared. Although this bright visible jet-producing object responsible for broad hydrogen emission lines with P Cygni profiles was widely considered to be a luminous blue variable ejecting matter, other studies posited the mentioned, competing, explanations for the bright light source within.
PHL 293 was first listed as entry 293 in a catalogue of faint blue stars published by Guillermo Haro and Willem Jacob Luyten in 1962. In 1965, Thomas Kinman observed two faint possible companions to it, about 1′ away, which he dubbed A and B. HL 293B, sometimes called Kinman's Dwarf, was noted to be an extragalactic, nonstellar object, with a jet, approximately 22.6 Mpc away from Earth. The acronym PHL has since been applied to distinguish it from other HL catalogues; it is most commonly referred to by astronomers as PHL 293B. The galaxy was identified as a blue compact dwarf, a type of small irregular galaxy undergoing a strong burst of star formation.
The spectrum of PHL 293B is unusual both for its low metallicity and for broad hydrogen emission lines with P Cygni profiles. These are interpreted as being from a large luminous blue variable star in the galaxy. The star is believed to have been undergoing an outburst during previous observations, an interpretation is disputed by some publications. An alternative explanation would be a long-lived type IIn supernova, similar to the transient event of SDSS1133. These emission features in the spectrum of the galaxy faded during 2019 and by the end of the year had disappeared (at least visibly), likely due to the disappearance of a bright star of the galaxy.
- French, H. B. (1980). "Galaxies with the spectra of giant H II regions". The Astrophysical Journal 240: 41. doi:10.1086/158205. Bibcode: 1980ApJ...240...41F.
- Guseva, N. G.; Papaderos, P.; Meyer, H. T.; Izotov, Y. I.; Fricke, K. J. (2009). "An investigation of the luminosity-metallicity relation for a large sample of low-metallicity emission-line galaxies". Astronomy & Astrophysics 505 (1): 63–72. doi:10.1051/0004-6361/200912414. Bibcode: 2009A&A...505...63G.
- Kinman, T. D. (1965). "The Nature of the Fainter Haro-Luyten Objects". The Astrophysical Journal 142: 1241. doi:10.1086/148392. Bibcode: 1965ApJ...142.1241K.
- Allan, Andrew P.; Groh, Jose H.; Mehner, Andrea; Smith, Nathan; Boian, Ioana; Farrell, Eoin J.; Andrews, Jennifer E. (2020). "The possible disappearance of a massive star in the low-metallicity galaxy PHL 293B". Monthly Notices of the Royal Astronomical Society 496 (2): 1902. doi:10.1093/mnras/staa1629. Bibcode: 2020MNRAS.496.1902A.
- Terlevich, Roberto; Terlevich, Elena; Bosch, Guillermo; Díaz, Ángeles; Hägele, Guillermo; Cardaci, Mónica; Firpo, Verónica (2014). "High-velocity blueshifted Fe ii absorption in the dwarf star-forming galaxy PHL 293B: Evidence for a wind driven supershell?". Monthly Notices of the Royal Astronomical Society 445 (2): 1449–1461. doi:10.1093/mnras/stu1806. Bibcode: 2014MNRAS.445.1449T.
- Izotov, Yuri I.; Thuan, Trinh X. (2009). "Luminous Blue Variable Stars in the two Extremely Metal-Deficient Blue Compact Dwarf Galaxies DDO 68 and PHL 293B". The Astrophysical Journal 690 (2): 1797–1806. doi:10.1088/0004-637X/690/2/1797. Bibcode: 2009ApJ...690.1797I.
- Haro, G.; Luyten, W. J. (1962). "Faint Blue Stars in the Region near the South Galactic Pole". Boletín de los Observatorios de Tonantzintla y Tacubaya 3: 37. Bibcode: 1962BOTT....3...37H.
- Burke, Colin J.; Baldassare, Vivienne F.; Liu, Xin; Foley, Ryan J.; Shen, Yue; Palmese, Antonella; Guo, Hengxiao; Herner, Kenneth et al. (2020). "The Curious Case of PHL 293B: A Long-lived Transient in a Metal-poor Blue Compact Dwarf Galaxy". The Astrophysical Journal 894 (1): L5. doi:10.3847/2041-8213/ab88de. Bibcode: 2020ApJ...894L...5B.
Original source: https://en.wikipedia.org/wiki/ PHL 293B. Read more