Yellow hypergiant

Intrinsic variable types in the Hertzsprung–Russell diagram showing the Yellow Hypergiants above (i.e. more luminous than) the Cepheid instability strip

A yellow hypergiant (YHG) is a massive star with an extended atmosphere, a spectral class from A to K, and, starting with an initial mass of about 20–60 solar masses, has lost as much as half that mass. They are amongst the most visually luminous stars, with absolute magnitude (MV) around −9, but also one of the rarest, with just 20 known in the Milky Way and six of those in just a single cluster. They are sometimes referred to as cool hypergiants in comparison with O- and B-type stars, and sometimes as warm hypergiants in comparison with red supergiants.

Classification

The term "hypergiant" was used as early as 1929, but not for the stars currently known as hypergiants.[1] Hypergiants are defined by their '0' luminosity class, and are higher in luminosity than the brightest supergiants of class Ia,[2] although they were not referred to as hypergiants until the late 1970s.[3] Another criterion for hypergiants was also suggested in 1979 for some other highly luminous mass-losing hot stars,[4] but was not applied to cooler stars. In 1991, Rho Cassiopeiae was the first to be described as a yellow hypergiant,[5] likely becoming grouped as a new class of luminous stars during discussions at the Solar physics and astrophysics at interferometric resolution workshop in 1992.[6]

Definitions of the term hypergiant remain vague, and although luminosity class 0 is for hypergiants, they are more commonly designated by the alternative luminosity classes Ia-0 and Ia+.[7] Their great stellar luminosities are determined from various spectral features, which are sensitive to surface gravity, such as Hβ line widths in hot stars or a strong Balmer discontinuity in cooler stars. Lower surface gravity often indicates larger stars, and hence, higher luminosities.[8] In cooler stars, the strength of observed oxygen lines, such as O I at 777.4 nm., can be used to calibrate directly against stellar luminosity.[9]

One astrophysical method used to definitively identify yellow hypergiants is the so-called Keenan-Smolinski criterion. Here all absorption lines should be strongly broadened, beyond those expected of bright supergiant stars, and also show strong evidence of significant mass loss. Furthermore, at least one broadened Hα component should also be present. They may also display very complex Hα profiles, typically having strong emission lines combined with absorption lines.[10]

The terminology of yellow hypergiants is further complicated by referring to them as either cool hypergiants or warm hypergiants, depending on the context. Cool hypergiants refers to all sufficiently luminous and unstable stars cooler than blue hypergiants and LBVs, including both yellow and red hypergiants.[11] The term warm hypergiants has been used for highly luminous class A and F stars in M31 and M33 that are not LBVs,[12] as well as more generally for yellow hypergiants.[13]

Characteristics

Visual light curve for ρ Cassiopeiae from 1933 to 2015

Yellow hypergiants occupy a region of the Hertzsprung–Russell diagram above the instability strip, a region where relatively few stars are found and where those stars are generally unstable. The spectral and temperature ranges are approximately A0-K2 and 4,000–8,000 K (3,730–7,730 °C; 6,740–13,940 °F) respectively. The area is bounded on the high-temperature side by the Yellow Evolutionary Void where stars of this luminosity become extremely unstable and experience severe mass loss. The “Yellow Evolutionary Void” separates yellow hypergiants from luminous blue variables although yellow hypergiants at their hottest and luminous blue variables at their coolest can have approximately the same temperature near 8,000 K. At the lower temperature bound, yellow hypergiants and red supergiants are not clearly separated; RW Cephei (roughly 4,000 K (3,730 °C; 6,740 °F), 295,000 L☉) is an example of a star that shares characteristics of both yellow hypergiants and red supergiants.[14][15]

Yellow hypergiants have a fairly narrow range of luminosities above 200,000 L☉ (e.g. V382 Carinae at 212,000 L☉) and below the Humphrey-Davidson limit at around 600,000 L☉. With their output peaking in the middle of the visual range, these are the most visually bright stars known with absolute magnitudes around −9 or −9.5 .[5]

They are large and somewhat unstable, with very low surface gravities. Where yellow supergiants have surface gravities (log g) below about 2, the yellow hypergiants have log g around zero. In addition they pulsate irregularly, producing small variations in temperature and brightness. This produces very high mass loss rates, and nebulosity is common around the stars.[16] Occasional larger outbursts can temporarily obscure the stars.[17]

Yellow hypergiants form from massive stars after they have evolved away from the main sequence. Most observed yellow hypergiants have been through a red supergiant phase and are evolving back towards higher temperatures, but a few are seen in the brief first transition from main sequence to red supergiant. Supergiants with an initial mass less than 20 M☉ will explode as a supernova while still red supergiants, while stars more massive than about 60 M☉ will never cool beyond blue supergiant temperatures. The exact mass ranges depend on metallicity and rotation.[18] Yellow supergiants cooling for the first time may be massive stars of up to 60 M☉ or more,[15] but post-red supergiant stars will have lost around half their initial mass.[19]

Chemically, most yellow hypergiants show strong surface enhancement of nitrogen and also of sodium and some other heavy elements. Carbon and oxygen are depleted, while helium is enhanced, as expected for a post-main-sequence star.

Evolution

Yellow hypergiants have clearly evolved off the main sequence and so have depleted the hydrogen in their cores. The majority of yellow hypergiants are postulated to be post-red supergiants evolving blueward,[14] while more stable and less luminous yellow supergiants are likely to be evolving to red supergiants for the first time. There is strong chemical and surface gravity evidence that the brightest of the yellow supergiants, HD 33579, is currently expanding from a blue supergiant to a red supergiant.[15]

These stars are doubly rare because they are very massive, initially hot class O-type main-sequence stars more than 15 times as massive as the Sun, but also because they spend only a few thousand years in the unstable yellow void phase of their lives. In fact, it is difficult to explain even the small number of observed yellow hypergiants, relative to red supergiants of comparable luminosity, from simple models of stellar evolution. The most luminous red supergiants may execute multiple "blue loops", shedding much of their atmosphere, but without actually ever reaching the blue supergiant stage, each one taking only a few decades at most. Conversely, some apparent yellow hypergiants may be hotter stars, such as the "missing" LBVs, masked within a cool pseudo-photosphere.[14]

Recent discoveries of blue supergiant supernova progenitors have also raised the question of whether stars could explode directly from the yellow hypergiant stage.[20] A handful of possible yellow supergiant supernova progenitors have been discovered, but they all appear to be of relatively low mass and luminosity, not hypergiants.[21][22] SN 2013cu is a type IIb supernova whose progenitor has been directly and clearly observed. It was an evolved star around 8,000 K (7,730 °C; 13,940 °F) showing extreme mass loss of helium and nitrogen enriched material. Although the luminosity is not known, only a yellow hypergiant or luminous blue variable in outburst would have these properties.[23]

Modern models suggest that stars with a certain range of masses and rotation rates may explode as supernovae without ever becoming blue supergiants again, but many will eventually pass right through the yellow void and become low-mass low-luminosity luminous blue variables and possibly Wolf–Rayet stars after that.[24] Specifically, more massive stars and those with higher mass loss rates due to rotation or high metallicity will evolve beyond the yellow hypergiant stage to hotter temperatures before reaching core collapse.[25]

Structure

IRAS 17163-3907 is a yellow hypergiant that clearly shows the expelled material that probably surrounds all yellow hypergiants.

According to the current physical models of stars, a yellow hypergiant should possess a convective core surrounded by a radiative zone, as opposed to a sun-sized star, which consists of a radiative core surrounded by a convective zone.[26] Because of their extreme luminosity and internal structure,[27] yellow hypergiants suffer high rates of mass loss[28] and are generally surrounded by envelopes of expelled material. An example of the nebulae that can result is IRAS 17163-3907, known as the Fried Egg, which has expelled several solar masses of material in just a few hundred years.[29]

The yellow hypergiant is an expected phase of evolution as the most luminous red supergiants evolve bluewards, but they may also represent a different sort of star. LBVs during eruption have such dense winds that they form a pseudo-photosphere which appears as a larger cooler star despite the underlying blue supergiant being largely unchanged. These are observed to have a very narrow range of temperatures around 8,000 K (7,730 °C; 13,940 °F). At the bistability jump which occurs around 21,000 K (20,700 °C; 37,300 °F) blue supergiant winds become several times denser and could be result in an even cooler pseudo-photosphere. No LBVs are observed just below the luminosity where the bistability jump crosses the S Doradus instability strip (not to be confused with the Cepheid instability strip), but it is theorised that they do exist and appear as yellow hypergiants because of their pseudo-photospheres.[30]

Known yellow hypergiants

Yellow hypergiant HR 5171 A, seen as the bright yellow star at the center of the image.
Artist's impression of the binary system containing yellow hypergiant HR 5171 A

In Milky Way galaxy

In other galaxies

References

  1. ^ Wallenquist, Aå (1929). "An attempt to determine the mean masses of the stars in the globular cluster M 3". Bulletin of the Astronomical Institutes of the Netherlands. 5: 67. Bibcode:1929BAN.....5...67W.
  2. ^ Morgan, William Wilson; Keenan, Philip Childs; Kellman, Edith (1943). "An atlas of stellar spectra, with an outline of spectral classification". Chicago. Bibcode:1943assw.book.....M.
  3. ^ De Jager, Cornelis (1980). "The Main Observational Characteristics of the Most Luminous Stars". The Brightest Stars. pp. 18–56. doi:10.1007/978-94-009-9030-2_2. ISBN 978-90-277-1110-6.
  4. ^ Llorente De Andres, F.; Lamers, H. J. G. L. M.; Muller, E. A. (1979). "Line Blocking in the Near Ultraviolet Spectrum of Early-Type Stars—Part Two—the Dependence on Spectral Type and Luminosity for Normal Stars". Astronomy and Astrophysics Supplement. 38: 367. Bibcode:1979A&AS...38..367L.
  5. ^ a b Zsoldos, E.; Percy, J. R. (1991). "Photometry of yellow semiregular variables - Rho Cassiopeiae". Astronomy and Astrophysics. 246: 441. Bibcode:1991A&A...246..441Z. ISSN 0004-6361.
  6. ^ De Jager, Cornelis; Nieuwenhuijzen, Hans (1992). "Yellow hypergiant interferometry: A clue to understanding evolutionary instability". In ESA. 344: 109. Bibcode:1992ESASP.344..109D.
  7. ^ Achmad, L.; Lamers, H. J. G. L. M.; Nieuwenhuijzen, H.; Van Genderen, A. M. (1992). "A photometric study of the G0-4 Ia(+) hypergiant HD 96918 (V382 Carinae)". Astronomy and Astrophysics. 259: 600. Bibcode:1992A&A...259..600A. ISSN 0004-6361.
  8. ^ Napiwotzki, R.; Schoenberner, D.; Wenske, V. (1993). "On the determination of effective temperature and surface gravity of B, A, and F stars using Stromgren UVBY beta photometry". Astronomy and Astrophysics. 268: 653. Bibcode:1993A&A...268..653N. ISSN 0004-6361.
  9. ^ Arellano Ferro, A.; Giridhar, S.; Rojo Arellano, E. (2003). "A Revised Calibration of the MV-W(O I 7774) Relationship using Hipparcos Data: Its Application to Cepheids and Evolved Stars". Revista Mexicana de Astronomía y Astrofísica. 39: 3. arXiv:astro-ph/0210695. Bibcode:2003RMxAA..39....3A.
  10. ^ a b c d e De Jager, C. (1998). "The yellow hypergiants". Astronomy and Astrophysics Review. 8 (3): 145–180. Bibcode:1998A&ARv...8..145D. doi:10.1007/s001590050009. S2CID 189936279.
  11. ^ Lobel, A.; De Jager, K.; Nieuwenhuijzen, H. (2013). "Long-term Spectroscopic Monitoring of Cool Hypergiants HR 8752, IRC+10420, and 6 Cas near the Yellow Evolutionary Void". 370 Years of Astronomy in Utrecht. Proceedings of a Conference Held 2–5 April. 470: 167. Bibcode:2013ASPC..470..167L.
  12. ^ Humphreys, Roberta M.; Davidson, Kris; Grammer, Skyler; Kneeland, Nathan; Martin, John C.; Weis, Kerstin; Burggraf, Birgitta (2013). "Luminous and Variable Stars in M31 and M33. I. The Warm Hypergiants and Post-Red Supergiant Evolution". The Astrophysical Journal. 773 (1): 46. arXiv:1305.6051. Bibcode:2013ApJ...773...46H. doi:10.1088/0004-637X/773/1/46. S2CID 118413197.
  13. ^ Shenoy, Dinesh; Humphreys, Roberta M.; Jones, Terry J.; Marengo, Massimo; Gehrz, Robert D.; Helton, L. Andrew; Hoffmann, William F.; Skemer, Andrew J.; Hinz, Philip M. (2016). "Searching for Cool Dust in the Mid-to-far Infrared: The Mass-loss Histories of the Hypergiants μ Cep, VY CMa, IRC+10420, and ρ Cas". The Astronomical Journal. 151 (3): 51. arXiv:1512.01529. Bibcode:2016AJ....151...51S. doi:10.3847/0004-6256/151/3/51. S2CID 119281306.
  14. ^ a b c Stothers, R. B.; Chin, C. W. (2001). "Yellow Hypergiants as Dynamically Unstable Post–Red Supergiant Stars". The Astrophysical Journal. 560 (2): 934. Bibcode:2001ApJ...560..934S. doi:10.1086/322438. hdl:2060/20010083764.
  15. ^ a b c Nieuwenhuijzen, H; de Jager, C (2000). "Checking the yellow evolutionary void. Three evolutionary critical Hypergiants: HD 33579, HR 8752 & IRC +10420". Astronomy and Astrophysics. 353: 163–176. Bibcode:2000A&A...353..163N.
  16. ^ Lobel, A.; Israelian, G.; de Jager, C.; Musaev, F.; Parker, J. W.; Mavrogiorgou, A. (1998). "The spectral variability of the cool hypergiant rho Cassiopeiae". Astronomy and Astrophysics. 330: 659–675. Bibcode:1998A&A...330..659L.
  17. ^ Lobel; Stefanik; Torres; Davis; Ilyin; Rosenbush (2003). "Spectroscopy of the Millennium Outburst and Recent Variability of the Yellow Hypergiant Rho Cassiopeiae". Stars as Suns: Activity. 219: 903. arXiv:astro-ph/0312074. Bibcode:2004IAUS..219..903L.
  18. ^ Groh, Jose H.; Meynet, Georges; Georgy, Cyril; Ekström, Sylvia (2013). "Fundamental properties of core-collapse supernova and GRB progenitors: Predicting the look of massive stars before death". Astronomy & Astrophysics. 558: A131. arXiv:1308.4681. Bibcode:2013A&A...558A.131G. doi:10.1051/0004-6361/201321906. S2CID 84177572.
  19. ^ Gesicki, K. (1992). "A Modelling of Circumstellar BAII Lines for the Hypergiant Rho-Cassiopeiae". Astronomy and Astrophysics. 254: 280. Bibcode:1992A&A...254..280G.
  20. ^ Langer, N.; Norman, C. A.; De Koter, A.; Vink, J. S.; Cantiello, M.; Yoon, S. -C. (2007). "Pair creation supernovae at low and high redshift". Astronomy and Astrophysics. 475 (2): L19. arXiv:0708.1970. Bibcode:2007A&A...475L..19L. doi:10.1051/0004-6361:20078482. S2CID 53516453.
  21. ^ Georgy, C. (2012). "Yellow supergiants as supernova progenitors: An indication of strong mass loss for red supergiants?". Astronomy & Astrophysics. 538: L8–L2. arXiv:1111.7003. Bibcode:2012A&A...538L...8G. doi:10.1051/0004-6361/201118372. S2CID 55001976.
  22. ^ Maund, J. R.; Fraser, M.; Ergon, M.; Pastorello, A.; Smartt, S. J.; Sollerman, J.; Benetti, S.; Botticella, M. -T.; Bufano, F.; Danziger, I. J.; Kotak, R.; Magill, L.; Stephens, A. W.; Valenti, S. (2011). "The Yellow Supergiant Progenitor of the Type II Supernova 2011dh in M51". The Astrophysical Journal. 739 (2): L37. arXiv:1106.2565. Bibcode:2011ApJ...739L..37M. doi:10.1088/2041-8205/739/2/L37. S2CID 118993104.
  23. ^ Groh, Jose H. (2014). "Early-time spectra of supernovae and their precursor winds". Astronomy & Astrophysics. 572: L11. arXiv:1408.5397. Bibcode:2014A&A...572L..11G. doi:10.1051/0004-6361/201424852. S2CID 118935040.
  24. ^ Smith, N.; Vink, J. S.; De Koter, A. (2004). "The Missing Luminous Blue Variables and the Bistability Jump". The Astrophysical Journal. 615 (1): 475–484. arXiv:astro-ph/0407202. Bibcode:2004ApJ...615..475S. doi:10.1086/424030. S2CID 17904692.
  25. ^ Chieffi, Alessandro; Limongi, Marco (2013). "Pre-Supernova Evolution of Rotating Solar Metallicity Stars in the Mass Range 13-120M☉And Their Explosive Yields". The Astrophysical Journal. 764 (1): 21. Bibcode:2013ApJ...764...21C. doi:10.1088/0004-637X/764/1/21.
  26. ^ Fadeyev, Y. A. (2011). "Pulsational instability of yellow hypergiants". Astronomy Letters. 37 (6): 403–413. arXiv:1102.3810. Bibcode:2011AstL...37..403F. doi:10.1134/S1063773711060016. S2CID 118642288.
  27. ^ Langer, Norbert; Heger, Alexander; García-Segura, Guillermo (1998). Reinhard E. Schielicke (ed.). "Massive Stars: The Pre-Supernova Evolution of Internal and Circumstellar Structure". Reviews in Modern Astronomy 11: Stars and Galaxies. 11. Hamburg: 57. Bibcode:1998RvMA...11...57L.
  28. ^ Dinh-v-Trung; Muller, S. B.; Lim, J.; Kwok, S.; Muthu, C. (2009). "Probing the Mass-Loss History of the Yellow Hypergiant IRC+10420". The Astrophysical Journal. 697 (1): 409–419. arXiv:0903.3714. Bibcode:2009ApJ...697..409D. doi:10.1088/0004-637X/697/1/409. S2CID 16971892.
  29. ^ Lagadec, E.; Zijlstra, A. A.; Oudmaijer, R. D.; Verhoelst, T.; Cox, N. L. J.; Szczerba, R.; Mékarnia, D.; Van Winckel, H. (2011). "A double detached shell around a post-red supergiant: IRAS 17163-3907, the Fried Egg nebula". Astronomy & Astrophysics. 534: L10. arXiv:1109.5947. Bibcode:2011A&A...534L..10L. doi:10.1051/0004-6361/201117521. S2CID 55754316.
  30. ^ Benaglia, P.; Vink, J. S.; Martí, J.; Maíz Apellániz, J.; Koribalski, B.; Crowther, P. A. (2007). "Testing the predicted mass-loss bi-stability jump at radio wavelengths". Astronomy and Astrophysics. 467 (3): 1265. arXiv:astro-ph/0703577. Bibcode:2007A&A...467.1265B. doi:10.1051/0004-6361:20077139. S2CID 14601449.
  31. ^ Keenan, P. C.; Pitts, R. E. (1980-04-01). "Revised MK spectral types for G, K ANS M stars". The Astrophysical Journal Supplement Series. 42: 541–563. Bibcode:1980ApJS...42..541K. doi:10.1086/190662. ISSN 0067-0049.
  32. ^ Keenan, P. C.; McNeil, R. C. (1989). "The Perkins catalog of revised MK types for the cooler stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
  33. ^ van Genderen, A. M.; Lobel, A.; Nieuwenhuijzen, H.; Henry, G. W.; de Jager, C.; Blown, E.; Di Scala, G.; van Ballegoij, E. J. (November 2019). "Pulsations, eruptions, and evolution of four yellow hypergiants". Astronomy & Astrophysics. 631: A48. arXiv:1910.02460. Bibcode:2019A&A...631A..48V. doi:10.1051/0004-6361/201834358. ISSN 0004-6361.
  34. ^ Davies, Ben; Figer, Don F.; Law, Casey J.; Kudritzki, Rolf-Peter; Najarro, Francisco; Herrero, Artemio; MacKenty, John W. (2008). "The Cool Supergiant Population of the Massive Young Star Cluster RSGC1". The Astrophysical Journal. 676 (2): 1016–1028. arXiv:0711.4757. Bibcode:2008ApJ...676.1016D. doi:10.1086/527350. S2CID 15639297.
  35. ^ Garcia, B. (1989-06-01). "A list of MK standard stars". Bulletin d'Information du Centre de Donnees Stellaires. 36: 27. Bibcode:1989BICDS..36...27G. ISSN 1169-8837.
  36. ^ Marco, A.; Negueruela, I.; González-Fernández, C.; Maíz Apellániz, J.; Dorda, R.; Clark, J. S. (2014-07-01). "VdBH 222: a starburst cluster in the inner Milky Way⋆". Astronomy and Astrophysics. 567: A73. arXiv:1405.7266. Bibcode:2014A&A...567A..73M. doi:10.1051/0004-6361/201423897. ISSN 0004-6361. S2CID 53533846.
  37. ^ Clark, J. S.; Ritchie, B. W.; Negueruela, I. (2013-12-01). "The circumstellar environment and evolutionary state of the supergiant B[e] star Wd1-9". Astronomy and Astrophysics. 560: A11. arXiv:1311.4792. Bibcode:2013A&A...560A..11C. doi:10.1051/0004-6361/201321412. ISSN 0004-6361. S2CID 53408838.
  38. ^ Messineo, Maria; Davies, Ben; Ivanov, Valentin D.; Figer, Donald F.; Schuller, Frederic; Habing, Harm J.; Menten, Karl M.; Petr-Gotzens, Monika G. (2009-05-01). "Near-Infrared Spectra of Galactic Stellar Clusters Detected on Spitzer/GLIMPSE Images". The Astrophysical Journal. 697 (1): 701–712. arXiv:0903.2238. Bibcode:2009ApJ...697..701M. doi:10.1088/0004-637X/697/1/701. ISSN 0004-637X. S2CID 15823676.
  39. ^ Clark, J. S.; Patrick, L. R.; Najarro, F.; Evans, C. J.; Lohr, M. (2021-05-01). "Constraining the population of isolated massive stars within the Central Molecular Zone". Astronomy and Astrophysics. 649: A43. arXiv:2102.08126. Bibcode:2021A&A...649A..43C. doi:10.1051/0004-6361/202039205. ISSN 0004-6361. S2CID 231934076.
  40. ^ Anugu, Narsireddy; Gies, Douglas R.; Roettenbacher, Rachael M.; Monnier, John D.; Montargés, Miguel; Mérand, Antoine; Baron, Fabien; Schaefer, Gail H.; Shepard, Katherine A.; Kraus, Stefan; Anderson, Matthew D.; Codron, Isabelle; Gardner, Tyler; Gutierrez, Mayra; Köhler, Rainer (September 2024). "Time Evolution Images of the Hypergiant RW Cephei during the Rebrightening Phase Following the Great Dimming". The Astrophysical Journal Letters. 973 (1): L5. arXiv:2408.11906. Bibcode:2024ApJ...973L...5A. doi:10.3847/2041-8213/ad736c. ISSN 2041-8205.
  41. ^ Humphreys, Roberta M.; Helmel, Greta; Jones, Terry J.; Gordon, Michael S. (2020-09-01). "Exploring the Mass-loss Histories of the Red Supergiants*". The Astronomical Journal. 160 (3): 145. arXiv:2008.01108. Bibcode:2020AJ....160..145H. doi:10.3847/1538-3881/abab15. ISSN 0004-6256.
  42. ^ Neugent, Kathryn F.; Massey, Philip; Skiff, Brian; Meynet, Georges (2012-04-20). "Yellow and Red Supergiants in the Large Magellanic Cloud". The Astrophysical Journal. 749 (2): 177. arXiv:1202.4225. Bibcode:2012ApJ...749..177N. doi:10.1088/0004-637X/749/2/177. ISSN 0004-637X.
  43. ^ a b c Chen, Kaitlyn M.; Dorn-Wallenstein, Trevor Z. (2024-03-01). "A Spectroscopic Hunt for Post-red Supergiants in the Large Magellanic Cloud. I. Preliminary Results". Research Notes of the American Astronomical Society. 8 (3): 75. arXiv:2403.08048. Bibcode:2024RNAAS...8...75C. doi:10.3847/2515-5172/ad32bb. ISSN 2515-5172.
  44. ^ a b Humphreys, R. M.; Weis, K.; Davidson, K.; Bomans, D. J.; Burggraf, B. (2014). "Luminous and Variable Stars in M31 and M33. II. Luminous Blue Variables, Candidate LBVs, Fe II Emission Line Stars, and Other Supergiants". The Astrophysical Journal. 790 (1): 48. arXiv:1407.2259. Bibcode:2014ApJ...790...48H. doi:10.1088/0004-637X/790/1/48. S2CID 119177378.
  45. ^ a b c d e Kourniotis, M.; Bonanos, A. Z.; Yuan, W.; Macri, L. M.; Garcia-Alvarez, D.; Lee, C.-H. (2017-05-01). "Monitoring luminous yellow massive stars in M 33: new yellow hypergiant candidates". Astronomy & Astrophysics. 601: A76. arXiv:1612.06853. Bibcode:2017A&A...601A..76K. doi:10.1051/0004-6361/201629146. ISSN 0004-6361.
  46. ^ a b c Kourniotis, M; Kraus, M; Maryeva, O; Borges Fernandes, M; Maravelias, G (2022-02-12). "Revisiting the evolved hypergiants in the Magellanic Clouds". Monthly Notices of the Royal Astronomical Society. 511 (3): 4360–4376. arXiv:2202.04667. doi:10.1093/mnras/stac386. ISSN 0035-8711.
  47. ^ Munoz-Sanchez, G.; et al. (28 November 2024). "The dramatic transition of the extreme Red Supergiant WOH G64 to a Yellow Hypergiant". arXiv:2411.19329.
  48. ^ a b c d e f g h i j k l m n Humphreys, Roberta M.; Stangl, Sarah; Gordon, Michael S.; Davidson, Kris; Grammer, Skyler H. (2019-01-01). "Luminous and Variable Stars in NGC 2403 and M81*". The Astronomical Journal. 157 (1): 22. arXiv:1811.06559. Bibcode:2019AJ....157...22H. doi:10.3847/1538-3881/aaf1ac. ISSN 0004-6256.

Read other articles:

KXII

CBS/MyNetworkTV/Fox affiliate in Sherman, Texas This article may be too long to read and navigate comfortably. Please consider splitting content into sub-articles, condensing it, or adding subheadings. Please discuss this issue on the article's talk page. (May 2022) KXII Sherman/Denison, Texas/Ada/Ardmore/Durant, OklahomaUnited StatesCitySherman, TexasChannelsDigital: 12 (VHF)Virtual: 12BrandingKXII 12 (general)12 Media (alternate)News 12 (newscasts)My12 (on DT2)Fox 12 (on DT3)ProgrammingAffi...

 

Universitas Kristen Indonesia Maluku

Universitas Kristen Indonesia MalukuLambang Universitas Kristen Indonesia MalukuMoto“Bertumbuh di dalam dan oleh Iman, Pengetahuan dan Kasih” (2 Petrus 1: 5-7)Moto dalam bahasa Inggris“Growing in and by Faith, Knowledge and Love” (2 Peter 1:5-7)JenisUniversitas SwastaRektorDr. Henky Herzon Hetharia, M.ThLokasiAmbon, Maluku, Indonesia3°42′09.02″S 128°10′20.5″E / 3.7025056°S 128.172361°E / -3.7025056; 128.172361 Universitas Kristen Indonesia Malu...

 

Voivodeship road 110

You can help expand this article with text translated from the corresponding article in Polish. Click [show] for important translation instructions. Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia. Do not translate text that appears unreliable or low-quality. If possibl...

Philibert Besson

Pour les articles homonymes, voir Besson. Philibert Besson Philibert Besson, photographie publiée dans une notice nécrologique. Fonctions Député 1932-1935 Gouvernement IIIe République Groupe politique NI Biographie Date de naissance 6 juin 1898 Lieu de naissance Vorey-sur-Arzon (Haute-Loire, France) Date de décès 16 mars 1941 (à 42 ans) Lieu de décès Riom (Puy-de-Dôme, France) modifier  Philibert Hippolyte Marcelin Besson, né le 6 juin 1898 à Vorey-sur-Arzon et mo...

 

Provinsi Adıyaman

Lokasi Provinsi Adıyaman di Turki Adıyaman adalah sebuah provinsi di tengah selatan Turki. Provinsi ini dimekarkan pada tahun 1954 dari Provinsi Malatya. Wilayahnya adalah 7.614 km² dan memiliki penduduk sebesar 623.811 jiwa (cacah jiwa 2000). Ibu kotanya adalah Adıyaman. Nemrud Dağı adalah sebuah situs arkeologi utama di provinsi ini. Situs ini terutama ternama sebagai suaka patung-patung yang dibangun oleh Antiochus Theos, raja Commagene. lbsDaftar provinsi Turki Adana ·...

 

ريدون آر 200

ريدون آر 200 (بالإنجليزية: Radeon R200)‏ وهو ثاني جيل من سلسلة ريدون من وحدات معالجة الرسوميات في شركة إيه تي آي.[1][2][3] وهي السلسلة التي أمّنت استمرارية شركة إي تي آي في حين كان معظم وحدات معالجة الرسوميات التابعة لشركات أخرى تبوء بالفشل، ورفعتها إلى مستوى متعادل مع شر...

Ryan Sailor

Questa voce sull'argomento calciatori statunitensi è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Ryan Sailor Sailor con i Washington Huskies (2021) Nazionalità  Stati Uniti Altezza 193 cm Peso 81 kg Calcio Ruolo Difensore Squadra  Inter Miami CarrieraGiovanili 2013-2016 Real ColoradoSquadre di club1 2016-2021 Washington Huskies49 (10)2017 Colorado Rapids U-230 (0)2022 Inter ...

 

Super Bowl XLV

Super Bowl XLV Ospiti Casa  Pittsburgh Steelers  Green Bay Packers (AFC) (NFC) 25 31 1 2 3 4 Totale PIT 0 10 7 8 25 GB 14 7 0 10 31 EdizioneXLV Data6 febbraio 2011 StadioCowboys Stadium CittàArlington, Texas MVPAaron Rodgers Inno nazionaleChristina Aguilera ArbitroWalt Anderson Halftime showThe Black Eyed Peas Spettatori103.219 Diffusione TV negli Stati Uniti d'AmericaReteFOX TelecronacaJoe Buck e Troy Aikman XLIV XLVI Il Super Bowl XLV è stato la 45ª edizione del ...

 

دوست ألان

دوست ألان تقسيم إداري البلد إيران  [1] إحداثيات 37°33′41″N 44°45′43″E / 37.56138889°N 44.76194444°E / 37.56138889; 44.76194444   السكان التعداد السكاني 193 نسمة (إحصاء 2016) الرمز الجغرافي 20890  تعديل مصدري - تعديل   دوست‌ ألان هي قرية في مقاطعة أرومية، إيران.[2] يقدر عدد سكانها �...

Rusli Noor

Rusli Noor Sekretaris Jenderal ASEAN ke-8Masa jabatan17 Juli 1989 – 1 Januari 1993PenggantiAjit Singh Informasi pribadiLahir1 Mei 1927 (umur 97)Bandung, Hindia Belanda (sekarang Indonesia)KebangsaanIndonesiaAlma materUniversitas ColumbiaProfesiDiplomatSunting kotak info • L • B Rusli Noor (lahir 1 Mei 1927) adalah sekretaris jenderal ASEAN dari tahun 1989 hingga 1993. Ia juga menjabat sebagai Direktur Eksekutif sekretariat APEC pada tahun 1994. Ia memperoleh gela...

 

Love Connection

American television dating game show This article is about the television game show. For the 1979 jazz music album, see The Love Connection. Love ConnectionGenreDating game showCreated byEric LieberDirected byPaul Miller[1]Deborah Miller[1]Tom McConnell[1]Presented byChuck WooleryPat BullardAndy CohenNarrated byRod RoddyGene WoodRich JeffriesJohnny GilbertJohn CervenkaCountry of originUnited StatesOriginal languageEnglishNo. of seasons11 (1983–1994)1 (1998–1999)2 (...

 

Penny (uang logam desimal Irlandia)

Uang logam desimal Penny Irlandia Uang logam desimal satu penny (1p) (bahasa Irlandia: pingin) adalah denominasi terkecil kedua pound Irlandia. Uang logam ini pertama kali dikeluarkan pada 15 Februari 1971 ketika desimalisasi mata uang Irlandia. Koin ini adalah salah satu dari tiga desain baru yang diperkenalkan di semua perunggu dan menampilkan burung hias yang dirancang oleh seniman Irlandia Gabriel Hayes di sebaliknya. Uang logam ini memiliki nilai 1/100 di pound Irlandia. Penny ditari...

IWI Tavor

Tavor redirects here. For other uses, see Tavor (disambiguation). Bullpup assault rifle IWI Tavor TAR-21 Tavor TAR-21 with MARS sight in the Israel Defense Forces History MuseumTypeBullpup assault riflePlace of originIsraelService historyIn service2001–present[1]Used bySee UsersWarsSouth Thailand insurgencyGaza–Israel conflictGaza War (2008–2009)Insurgency in Jammu and Kashmir2014 Israel–Gaza conflictSecond Nagorno-Karabakh warColombian conflictRusso-Ukrain...

 

The Care Bears Battle the Freeze Machine

1984 Canadian TV series or program The Care Bears Battle the Freeze MachineA poster for the original May 1984 video release of the specialWritten byPeter SauderDirected byPino van Lamsweerde,Paul Schibli (animation)StarringRick JonesBob DermerNoreen YoungLes LyeAbby HagyardDominic BradfordBrodie OsomeNarrated byBob DermerTheme music composerBob and Merry Chimbel (songs),Gary Morton (score)Country of originCanadaOriginal languageEnglishProductionProducersW.H. Stevens Jr.Hugh CampbellCinematog...

 

أنواع القومية

  كثير من العلماء[من؟] يجادلون بأن هناك أكثر من نوع واحد من القومية. قد تعبر القومية عن نفسها كجزء من أيديولوجية الدولة الرسمية أو كحركة شعبية غير حكومية ويمكن التعبير عنها على أسس مدنية، عرقية، ثقافية، لغوية، دينية، أو أيديولوجية. تستخدم هذه التعريفات الذاتية للأمة ...

Conrail Shared Assets Operations

American railroad company This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article includes a list of general references, but it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations. (December 2010) (Learn how and when to remove this message) This article needs additional citations for verification. Please help impr...

 

Sveriges allmänna konstförening

Titelsidan till katalogen för Stockholms konstförenings första utställning 1832. Katalogen är sammanställd av Axel Gabriel Bielke och har titeln Catalog öfver Konst-föreningens offentliga exposition af gamle mästares arbeten; öppnad i april 1832. Sveriges Allmänna Konstförening (SAK) är en svensk ideell förening som syftar till att stödja svenskt konstliv. Detta sker genom att varje år köpa in verk av nu aktiva konstnärer som årligen lottas ut till medlemmarna. Föreningen ...

 

Vokrug sveta

Russian geographic magazine Vokrug svetaAn illustration from the 1861 issue of Vokrug sveta.CategoriesGeographyFounded1861CountryRussiaBased inSaint PetersburgLanguageRussianWebsitehttp://www.vokrugsveta.ru/ Vokrug sveta (Russian: Вокруг света, literally: Around the World) is a Russian geographic magazine. It is the longest running magazine in the Russian language. The first issue was printed in Saint Petersburg, in December 1861, almost thirty years before the establishment of the...

Dalton Castle

Dalton CastleCastle pada tahun 2015Nama lahirBrett GiehlLahir04 Maret 1986 (umur 38)Rochester, New York, Amerika Serikat[1]Karier gulat profesionalNama ringAshley Remington[2]Brett Giehl[3]Dalton Caroline Castle[4]Dalton Castle[5]Tinggi5 ft 11 in (180 cm)[6]Berat217 pon (98 kg)[7]Asal dariCatalina Island (di ROH)[6]The Open Waters (di Chikara)[2]Debut2009[5] Brett Giehl[8][...

 

Area naturale marina protetta Portofino

Area naturale marina protetta di Portofino Tipo di areaArea marina protetta Codice WDPA5977 Codice EUAPEUAP0949 Class. internaz.Sito di interesse comunitario Stati Italia RegioniLiguria ProvinceGenova ComuniCamogli, Portofino, Santa Margherita Ligure Superficie a mare346[1] ha Provvedimenti istitutiviD.M. 26.04.99 GestoreConsorzio di Gestione Area Marina Protetta del Promontorio di Portofino PresidenteOreste Bozzo Mappa di localizzazione Sito istituzionale Modifica dati su Wikida...