The extinction value for HM 1 is calculated to be EB−V = 1.85 magnitudes, and its distance was first estimated to be around 2.9 ± 0.4 kiloparsecs away.[5] Later estimates put the cluster at around 3.3 kiloparsecs away; this is still one of the more closer massive star clusters.[2]
HM 1 is fairly young for an open cluster; it is estimated to be 1 to 2, or 2 to 4 million years old.[6] This is indicated by the presence of Of stars, which have relatively short lives. However, a red supergiant with a bolometric magnitude of −6.6 and a mass of about 20 M☉ was discovered near the cluster, contradicting the supposed age of the cluster.[7] However, subsequent work showed the star is likely in the foreground.[2]
Compositionedit
HM 1 is noted for its components, including several Wolf–Rayet stars and Of stars. Both types of stars are fairly rare and very massive, and their coexistence in star clusters was unexpected. The evolution of Wolf–Rayet stars and Of stars in star clusters is currently unclear. Very few Wolf–Rayet stars have been found in star clusters, and a possible explanation is that the formation of these cluster Wolf–Rayet stars requires a binary star system containing two Of stars. Alternatively, cluster Wolf–Rayet stars may simply be rare because they represent a short stage in the evolution of Of stars, whether single or binary.[5]
Many of the stellar components are extremely blue-colored O-type stars that are among some of the most luminous stars known. Some of the candidate members listed have masses of over 20 M☉, making this cluster one of the richest known.[6] Examples include the peculiar starLSS 4067, an O-type supergiant with a spectral type of O4If+.[4] WR 89, another luminous star, is a strong X-ray source and is possibly a colliding-wind binary, based on data from XMM-Newton.[6] In contrast, WR 87 has a high plasma temperature consistent with that of a colliding-wind binary but otherwise appears to be a single star (similar to WR 136).[4]
^ abKharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (2013). "Global survey of star clusters in the Milky Way". Astronomy & Astrophysics. 558: A53. arXiv:1308.5822. Bibcode:2013A&A...558A..53K. doi:10.1051/0004-6361/201322302. S2CID 118548517.
^ abcdefgVázquez, R. A.; Baume, G. (2001). "The open cluster Havlen-Moffat No. 1 revisited". Astronomy and Astrophysics. 371 (3): 908–920. Bibcode:2001A&A...371..908V. doi:10.1051/0004-6361:20010410.
^Morales, Esteban F. E.; Wyrowski, Friedrich; Schuller, Frederic; Menten, Karl M. (2013). "Stellar clusters in the inner Galaxy and their correlation with cold dust emission". Astronomy & Astrophysics. 560: A76. arXiv:1310.2612. Bibcode:2013A&A...560A..76M. doi:10.1051/0004-6361/201321626. S2CID 118422539.
^ abcdefghijklmMassey, P.; Degioia-Eastwood, K.; Waterhouse, E. (2001). "The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs. II. Results from 12 Galactic Clusters and OB Associations". The Astronomical Journal. 121 (2): 1050–1070. arXiv:astro-ph/0010654. Bibcode:2001AJ....121.1050M. doi:10.1086/318769. S2CID 53345173.
^ abcHavlen, R. J.; Moffat, A. F. J. (1977). "A new cluster containing 2 Wolf-Rayet-stars and 2 Of-stars". Astronomy and Astrophysics. 58 (3): 351–356. Bibcode:1977A&A....58..351H.
^ abcNazé, Y.; Rauw, G.; Sana, H.; Corcoran, M. F. (2013). "X-ray properties of the young open clusters HM1 and IC 2944/2948". Astronomy & Astrophysics. 555: A83. arXiv:1305.5105. Bibcode:2013A&A...555A..83N. doi:10.1051/0004-6361/201321099. S2CID 119231082.
^The, P. S.; Arens, M.; van der Hucht, K. A. (1982). "An investigation of the Scorpius open cluster C1715-387 containing two WN7, two Of and one red supergiant members". Astrophysical Letters. 22: 109. Bibcode:1982ApL....22..109T.
^ abcdSota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J.; Oskinova, L. M. (2019). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy & Astrophysics. A57: 625. arXiv:1904.04687. Bibcode:2019A&A...625A..57H. doi:10.1051/0004-6361/201834850. S2CID 104292503.
^Rodríguez, C. N.; Ferrero, G. A.; Benvenuto, O. G.; Gamen, R.; Morrell, N. I.; Barbá, R. H.; Arias, J.; Massey, P. (2021). "Fundamental parameters of the massive eclipsing binary HM1 8". Monthly Notices of the Royal Astronomical Society. 508 (2): 2179–2193. arXiv:2109.13054. doi:10.1093/mnras/stab2699.
Notesedit
^These numbers are not the same as the ones used in SIMBAD. For example, HM 1 6 (WR 87) is [NRS2013] HM1 6, not Cl HM 1 6.
^This is a binary star system. Parameters, if two are provided, refer to the primary and secondary, respectively.
January 01, 1970
also, known, havlen, moffat, open, cluster, located, constellation, scorpius, close, galactic, plane, first, observed, havlen, moffat, 1976, thought, light, years, parsecs, away, from, earth, beyond, carina, sagittarius, heavily, reddened, interstellar, extinc. HM 1 also known as Havlen Moffat 1 is an open cluster located in the constellation of Scorpius close to the galactic plane It was first observed by R J Havlen and A F J Moffat in 1976 5 HM 1 is thought to be 9 500 to 12 700 light years 2 900 to 3 900 parsecs away from the Earth beyond the Carina Sagittarius Arm 2 It is heavily reddened by interstellar extinction so although it comprises mostly blue colored stars it appears brighter for longer wavelength passbands 2 It is projected against the H II region known as RCW 121 and appears to be the source of ionization for the nearby regions RCW 122 and RCW 123 2 HM 1 Havlen Moffat 1 Approximate location of HM 1 circled Observation data J2000 epoch Right ascension17h 18m 54s 1 Declination 38 49 01 1 Distance9 500 12 700 ly 2 900 3 900 pc 2 Apparent dimensions V 5 3 Physical characteristicsEstimated age1 2 Myr 4 2 4 Myr 2 Star cluster rich in massive starsOther designationsC 1715 387AssociationsConstellationScorpiusSee also Open cluster List of open clusters Contents 1 Properties 2 Composition 3 Gallery 4 See also 5 References 6 NotesProperties editThe extinction value for HM 1 is calculated to be EB V 1 85 magnitudes and its distance was first estimated to be around 2 9 0 4 kiloparsecs away 5 Later estimates put the cluster at around 3 3 kiloparsecs away this is still one of the more closer massive star clusters 2 HM 1 is fairly young for an open cluster it is estimated to be 1 to 2 or 2 to 4 million years old 6 This is indicated by the presence of Of stars which have relatively short lives However a red supergiant with a bolometric magnitude of 6 6 and a mass of about 20 M was discovered near the cluster contradicting the supposed age of the cluster 7 However subsequent work showed the star is likely in the foreground 2 Composition editHM 1 is noted for its components including several Wolf Rayet stars and Of stars Both types of stars are fairly rare and very massive and their coexistence in star clusters was unexpected The evolution of Wolf Rayet stars and Of stars in star clusters is currently unclear Very few Wolf Rayet stars have been found in star clusters and a possible explanation is that the formation of these cluster Wolf Rayet stars requires a binary star system containing two Of stars Alternatively cluster Wolf Rayet stars may simply be rare because they represent a short stage in the evolution of Of stars whether single or binary 5 Many of the stellar components are extremely blue colored O type stars that are among some of the most luminous stars known Some of the candidate members listed have masses of over 20 M making this cluster one of the richest known 6 Examples include the peculiar star LSS 4067 an O type supergiant with a spectral type of O4If 4 WR 89 another luminous star is a strong X ray source and is possibly a colliding wind binary based on data from XMM Newton 6 In contrast WR 87 has a high plasma temperature consistent with that of a colliding wind binary but otherwise appears to be a single star similar to WR 136 4 Properties of HM 1 cluster members Name note 1 Teff MV Mbol Mass M Spectral type Ref HM 1 1 WR 89 39800 7 56 11 09 87 8 WN8h 8 HM 1 2 LSS 4067 47800 7 0 11 4 120 O4If 4 HM 1 3 WR 87 44700 6 95 10 79 59 8 WN7h 8 HM 1 6 45000 6 5 10 7 95 O5If 4 HM 1 8 note 2 41200 34500 5 2 3 7 10 4 26 8 lt 9 7 O4 5IV f O9 7V 9 HM 1 9 37900 5 3 8 9 38 4 HM 1 12 41900 5 5 9 5 50 O6If 4 HM 1 13 41000 5 3 9 2 44 O7V f 4 HM 1 16 33100 5 4 8 7 32 4 HM 1 18 38100 4 4 8 1 29 4 HM 1 19 39300 4 1 7 8 28 4 HM 1 20 34700 4 1 7 4 22 O9 5V 4 Gallery edit nbsp Near Infrared image of HM1 taken with ESO s VISTA Some cluster members are marked nbsp Spitzer mid infrared view of the environment of the cluster including RCW 121 and RCW 122 at the bottom See also editCygnus OB2 an OB association containing many massive stars List of most massive starsReferences edit a b Kharchenko N V Piskunov A E Schilbach E Roser S Scholz R D 2013 Global survey of star clusters in the Milky Way Astronomy amp Astrophysics 558 A53 arXiv 1308 5822 Bibcode 2013A amp A 558A 53K doi 10 1051 0004 6361 201322302 S2CID 118548517 a b c d e f g Vazquez R A Baume G 2001 The open cluster Havlen Moffat No 1 revisited Astronomy and Astrophysics 371 3 908 920 Bibcode 2001A amp A 371 908V doi 10 1051 0004 6361 20010410 Morales Esteban F E Wyrowski Friedrich Schuller Frederic Menten Karl M 2013 Stellar clusters in the inner Galaxy and their correlation with cold dust emission Astronomy amp Astrophysics 560 A76 arXiv 1310 2612 Bibcode 2013A amp A 560A 76M doi 10 1051 0004 6361 201321626 S2CID 118422539 a b c d e f g h i j k l m Massey P Degioia Eastwood K Waterhouse E 2001 The Progenitor Masses of Wolf Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs II Results from 12 Galactic Clusters and OB Associations The Astronomical Journal 121 2 1050 1070 arXiv astro ph 0010654 Bibcode 2001AJ 121 1050M doi 10 1086 318769 S2CID 53345173 a b c Havlen R J Moffat A F J 1977 A new cluster containing 2 Wolf Rayet stars and 2 Of stars Astronomy and Astrophysics 58 3 351 356 Bibcode 1977A amp A 58 351H a b c Naze Y Rauw G Sana H Corcoran M F 2013 X ray properties of the young open clusters HM1 and IC 2944 2948 Astronomy amp Astrophysics 555 A83 arXiv 1305 5105 Bibcode 2013A amp A 555A 83N doi 10 1051 0004 6361 201321099 S2CID 119231082 The P S Arens M van der Hucht K A 1982 An investigation of the Scorpius open cluster C1715 387 containing two WN7 two Of and one red supergiant members Astrophysical Letters 22 109 Bibcode 1982ApL 22 109T a b c d Sota A Maiz Apellaniz J Morrell N I Barba R H Walborn N R Gamen R C Arias J I Alfaro E J Oskinova L M 2019 The Galactic WN stars revisited Impact of Gaia distances on fundamental stellar parameters Astronomy amp Astrophysics A57 625 arXiv 1904 04687 Bibcode 2019A amp A 625A 57H doi 10 1051 0004 6361 201834850 S2CID 104292503 Rodriguez C N Ferrero G A Benvenuto O G Gamen R Morrell N I Barba R H Arias J Massey P 2021 Fundamental parameters of the massive eclipsing binary HM1 8 Monthly Notices of the Royal Astronomical Society 508 2 2179 2193 arXiv 2109 13054 doi 10 1093 mnras stab2699 Notes edit These numbers are not the same as the ones used in SIMBAD For example HM 1 6 WR 87 is NRS2013 HM1 6 not Cl HM 1 6 This is a binary star system Parameters if two are provided refer to the primary and secondary respectively Retrieved from https en wikipedia org w index php title HM 1 amp oldid 1172492904, wikipedia, wiki, book, books, library,
