Sagittarius A*

Cave ne confundas cum notione hac: Sagittarius A.

Sagittarius A* (sagittarius-a-stella articulandus) vel, forma compendiaria, Sgr A*, est foramen nigrum supermassivum^(en)(d) (~ 4300000 M_☉, ~ 18 R_☉) in centro^(en)(d) Viae lacteae situm. Invenitur apud fines inter constellationes Sagittarii et Scorpii, circa 5.6° australius quam linea ecliptica, prope cumulum Papilionis^(en)(d) (M6) et Lambda Scorpii^(en)(d). A Tellure fere 27000 annos luce mensos distat.

Tempus hac pellicula ostentum est 20 annorum. In parte media latet Sagittarius A*, cuius debiles deflagrationes, disperse, videri possunt. Notabiles sunt orbitae stellarum, quae circa vacuum moveri videntur.

Corpus est densissimus et luminosissimus fons radioelectricus^(en)(d), cuius ipsa luminositas fuit causa nominis. Anno quidem 1954, cum astronomi Ioannes Kraus^(en), Hsien-Ching Ko, et Ioannes Matt, radiotelescopio^(d) Universitatis Civicae Ohiensis utentes, aliquos fontes radioelectricos ab eis inventos frequentiā 250 MHz auscultavissent et in tabulam astronomicam^(en) notavissent, litteram capitaneam ordine luminositatis decrescente cuique fonti apposuerunt, ubi littera A fons luminosissimus indicabat.^[1]

Asteriscus (*) – hodie "stella" articulatus, quasi stellam pingens – fuit appendicula posterior, anno 1982 a Roberto L. Brown addita, cum is tales validissimas emissiones intellexisset ex corpore compacto non thermico oriri.^[2] Ratio asterisci fuit imitatio nomenclaturae chemicae, ubi excitatio atomica eodem signo notatur (exempli gratia, status excitatus helii notatur "He*"), quoniam haec quidem inventio etiam putabatur "excitans".^[3] Hodie nomen sine asterisco, Sagittarius A, fontem radioelectricum compositum indicat, in quo Sagittarius A Orientalis, Sagittarius A Occidentalis et Sagittarius A* numerantur.

Observatio plurium stellarum circum Sagittarium A* moventium, praecipue stellae S2^(en)(d), massam limitemque superiorem radii corporis compacti determinare sivit. Massā radioque magis magisque definitis, astronomi statuere potuerunt Sagittarium A* putandum esse Viae lacteae foramen nigrum supermassivum centrale.^[4] Haec massa hodie aestimatur 4.297 ± 0.012 millionibus massarum solarium.^[5] Tali massae radius Schwarzschildianus fere 12690500 km, vel 18.22 R_☉, vel 0.08 UA (i.e. paulum plus quam quinta pars semiaxis maioris orbitae Mercurii), congruit.

Sagittario A* demonstrato corpore supermassivo et compacto, Reinhardus Genzel et Andrea M. Ghez Praemium Nobelianum physicae anno 2020 acciperunt.^[6] Illā massā illoque radio sola facies tunc nota erat foraminis nigri.

Mense Maii 2022, astronomi, telescopio Horizonte Eventuum^(d) utentes (quod est rete mundiale observatoriorum radioelectricorum), primam imaginem disci accretionis^(en)(d) circum horizontem eventuum Sagittarii A* ediderunt.^[7] Talis imago naturam foramini nigri confirmavit et fuit secunda imago certa unius ex his corporibus post illam foramini nigri supermassivi galaxiae Messier 87 anni 2019.^[8]^[9] Haud ipsum foramen nigrum in photographemate videri poterat, sed materies tantum quae id circumdabat. Talis materies ex pulvere et gase consistit, qui cum in foramen nigrum incidant millionibus gradibus calefiunt.^[10]

Notae

↑ Kraus, J. D.; Ko, H. C.; Matt, S. (Decembre 1954). "Galactic and localized source observations at 250 megacycles per second.". The Astronomical Journal 59: 439–443
↑ Brown, Robertus L. (1 Novembris 1982). "Precessing Jets in Sagittarius A: Gas Dynamics in the Central Parsec of the Galaxy". The Astrophysical Journal 262: 110–119
↑ Goss, W. M.; Brown, Robert L.; Lo, K. Y. (8 Augusti 2003). "The Discovery of Sgr A*". Astronomische Nachrichten 324 (S1): 497–504. arXiv:astro-ph/0305074
↑ Henderson, Mark (9 Decembris 2009). "Astronomers confirm black hole at the heart of the Milky Way". Times Online
↑ The GRAVITY collaboration (Septembre 2023). "Polarimetry and astrometry of NIR flares as event horizon scale, dynamical probes for the mass of Sgr A*". Astronomy & Astrophysics 677: L10
↑ "The Nobel Prize in Physics 2020". 6 Octobris 2020
↑ Bower, Geoffrey C. (May 2022). "Focus on First Sgr A* Results from the Event Horizon Telescope". The Astrophysical Journal
↑ "Astronomers reveal first image of the black hole at the heart of our galaxy". eso.org. 12 May 2022
↑ Overbye, Dennis (2022-05-12). "The Milky Way's Black Hole Comes to Light". The New York Times
↑ Abuter, R.; Amorim, A.; Bauböck, M.; Berger, J. P.; Bonnet, H.; Brandner, W.; Clénet, Y.; Coudé Du Foresto, V. et al (2018). "Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA". Astronomy & Astrophysics 618: L10. arXiv:1810.12641

Nexus interni

Nexus externi

Vicimedia Communia plura habent quae ad Sagittarium A* spectant.

[1] Kraus, J. D.; Ko, H. C.; Matt, S. (Decembre 1954). "Galactic and localized source observations at 250 megacycles per second.". The Astronomical Journal 59: 439–443

[2] Brown, Robertus L. (1 Novembris 1982). "Precessing Jets in Sagittarius A: Gas Dynamics in the Central Parsec of the Galaxy". The Astrophysical Journal 262: 110–119

[3] Goss, W. M.; Brown, Robert L.; Lo, K. Y. (8 Augusti 2003). "The Discovery of Sgr A*". Astronomische Nachrichten 324 (S1): 497–504. arXiv:astro-ph/0305074

[Henderson-4] Henderson, Mark (9 Decembris 2009). "Astronomers confirm black hole at the heart of the Milky Way". Times Online

[the-gravity-collaboration-5] The GRAVITY collaboration (Septembre 2023). "Polarimetry and astrometry of NIR flares as event horizon scale, dynamical probes for the mass of Sgr A*". Astronomy & Astrophysics 677: L10

[6] "The Nobel Prize in Physics 2020". 6 Octobris 2020

[AJ-202205-7] Bower, Geoffrey C. (May 2022). "Focus on First Sgr A* Results from the Event Horizon Telescope". The Astrophysical Journal

[ESO2208-8] "Astronomers reveal first image of the black hole at the heart of our galaxy". eso.org. 12 May 2022

[NYT-20220512-9] Overbye, Dennis (2022-05-12). "The Milky Way's Black Hole Comes to Light". The New York Times

[DetectionOfBlackHoleSrgA-10] Abuter, R.; Amorim, A.; Bauböck, M.; Berger, J. P.; Bonnet, H.; Brandner, W.; Clénet, Y.; Coudé Du Foresto, V. et al (2018). "Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA". Astronomy & Astrophysics 618: L10. arXiv:1810.12641

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