سعد الملك
  | |
| بيانات الرصـد الحقبة J2000.0 اعتدال J2000.0 (ICRS) | |
|---|---|
| الكوكبة | Aquarius |
| الصعود المستقيم | 22h 05m 47.03593s[1] |
| الميل | −00° 19′ 11.4568″[1] |
| القدر الظاهري (V) | 2.942[2] |
| الخـصـائص | |
| النوع الطيفي | G2 Ib[3] |
| U-B دليل الألوان | +0.699[2] |
| B-V دليل الألوان | +0.971[2] |
| R-I دليل الألوان | +0.49[2] |
| علم القياسات الفلكية | |
| السرعة القطرية (Rv) | 7.5[4] كم/ث |
| الحركة الحقيقية (μ) | RA: +18.25[1] mas/yr Dec.: −9.39[1] mas/س |
| اختلاف المنظر (π) | 6.23 ± 0.19[1] mas |
| المسافة | س ض ( ف ن) |
| القدر المطلق (MV) | −3.882[5] |
| التـفـاصـيل | |
| الكتلة | 5.13±0.06[6] M☉ |
| نصف القطر | 52.89+1.68 −1.78[6] R☉ |
| جاذبية السطح (log g) | 1.76±0.04[3] |
| الضياء | 2,120±167[6] L☉ |
| درجة الحرارة | 5,383±74[6] ك |
| سرعة الدوران (v sin i) | 6.7±1.5[7] كم/ث |
| تسميات أخرى | |
| مراجع قواعد البيانات | |
| SIMBAD | data |
سعد الملك أو ألفا الدلو Alpha Aquarii اسمه التقليدي Sadalmelik مشتق من الاسم العربي. و هو نجم في كوكبة الدلو . وهو ثاني ألمع النجوم في كوكبة الدلو. و ينتمي إلى الفئة الطيفية G [8]و هو عملاق عظيم أصفر ويبلغ القدر الظاهري له تقريبا 2.95+ و يبعد حوالي 800 سنة ضوئية عن الأرض. ويبلغ قطره حوالي 600 ضعف قطر الشمس و ضياءه حوالي 300 ضعف ضياء الشمس [11]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
الخصائص
With an age of 53 million years,[3] Alpha Aquarii has evolved into a supergiant with a stellar classification of G2 Ib.[3] It lies within the Cepheid instability strip of the Hertzsprung–Russell diagram, near the red (cooler) edge, but is not classified as a variable star. However, variable cores have been detected in the hydrogen lines, which are originating in a circumstellar envelope.[12] The star has a massive stellar wind that reaches supersonic velocity in the chromosphere.[13]
Alpha Aquarii has 5.1[6] times as much mass as the Sun and has expanded to around 53[6] times the Sun's radius. It is radiating 2,100[6] times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 5,383 K.[6] At this heat, the star glows with the yellow hue of a G-type star.[14] Examination of this star with the Chandra X-ray Observatory shows it to be significantly X-ray deficient compared to G-type main-sequence stars. This deficit is a common feature of early G-type giant stars.[7]
The visual companion (UCAC2 31789179) has an apparent visual magnitude of approximately 12.2. It is at an angular separation of 110.4 arcseconds from Alpha Aquarii along a position angle of 40°.[10]
انظر أيضا
المراجع
- ^ أ ب ت ث ج van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:, Bibcode: 2007A&A...474..653V
- ^ أ ب ت ث Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars 8: 59, Bibcode: 1984SAAOC...8...59C
- ^ أ ب ت ث Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (February 2010), "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society 402 (2): 1369–1379, doi:, Bibcode: 2010MNRAS.402.1369L
- ^ Wielen, R.; Schwan, H.; Dettbarn, C.; Lenhardt, H.; Jahreiß, H.; Jährling, R. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode: 1999VeARI..35....1W
- ^ Soubiran, C.; et al. (2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics. 480 (1): 91–101. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. S2CID 16602121.
- ^ أ ب ت ث ج ح خ د Baines, Ellyn K.; et al. (2018). "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 155 (1). 30. arXiv:1712.08109. Bibcode:2018AJ....155...30B. doi:10.3847/1538-3881/aa9d8b.
- ^ أ ب Ayres, Thomas R.; Brown, Alexander; Harper, Graham M. (July 2005), "Chandra Observations of Coronal Emission from the Early G Supergiants α and β Aquarii", The Astrophysical Journal 627 (1): L53–L56, doi:, Bibcode: 2005ApJ...627L..53A
- ^ أ ب HR 8414, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line October 3, 2008.
- ^ NAME SADALMELIK -- Star in double system, database entry, SIMBAD. Accessed on line October 3, 2008.
- ^ أ ب Entry 22058-0019, The Washington Double Star Catalog Archived 2009-01-31 at the Wayback Machine, United States Naval Observatory. Accessed on line November 18, 2008.
- ^ أ ب pp. 51, 148, Star-names and Their Meanings, Richard Hinckley Allen, New York: G. E. Stechert, 1899.
- ^ Usenko, I. A.; Miroshnichenko, A. S.; Danford, S. (November 2017), "Spectroscopic studies of the unique yellow supergiant α Aqr in the Cepheid instability strip", Astronomy Letters 43 (11): 751–767, doi:, Bibcode: 2017AstL...43..751U.
- ^ Dupree, A. K.; Sasselov, D. D.; Keener, S. R. (December 1993), "HST/GHRS Spectroscopy of the Hybrid Star Alpha Aquarii", Bulletin of the American Astronomical Society (American Astronomical Society, 183rd AAS Meeting) 25: 1321, 18.07, Bibcode: 1993AAS...183.1807D.
- ^ The Colour of Stars, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved on 2012-01-16
<ref> ذو الاسم "kaler" المُعرّف في <references> غير مستخدم في النص السابق.وصلات خارجية
- Alpha Aquarii Aladin image viewer
