التصنيف النجمي
تصنيف مورگان كينان الطيفي Morgan-Keenan spectral classification هو طريقة أو أسلوب في التصنيف، تصنف فيه النجوم السماوية على وفق نمطها الطيفي وطبقة تألقها.
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مراتب سـِكي
| الترتيب | Temperature[1] (كلڤن) |
اللون المعتاد | Apparent color[2]خطأ استشهاد: إغلاق </ref> مفقود لوسم <ref>[3][4]
|
Mass[1] (الكتل الشمسية) |
نق[1] (أنصاف الأقطار الشمسية) |
التألق[1] (bolometric) |
خطوط الهيدروجين |
جزء من كل main sequence stars[5] |
|---|---|---|---|---|---|---|---|---|
| O | ≥ 30,000 K | blue | blue | ≥ 16 M☉ | ≥ 6.6 R☉ | ≥ 30,000 L☉ | ضعيف | ~0.00003% |
| B | 10,000–30,000 K | أزرق إلى أزرق أبيض | أزرق أبيض | 2.1–16 M☉ | 1.8–6.6 R☉ | 25–30,000 L☉ | متوسط | 0.13% |
| A | 7,500–10,000 K | white | أبيض إلى أزرق أبيض | 1.4–2.1 M☉ | 1.4–1.8 R☉ | 5–25 L☉ | Strong | 0.6% |
| F | 6,000–7,500 K | أبيض مصفر | أبيض | 1.04–1.4 M☉ | 1.15–1.4 R☉ | 1.5–5 L☉ | Medium | 3% |
| G | 5,200–6,000 K | yellow | yellowish white | 0.8–1.04 M☉ | 0.96–1.15 R☉ | 0.6–1.5 L☉ | Weak | 7.6% |
| K | 3,700–5,200 K | orange | yellow orange | 0.45–0.8 M☉ | 0.7–0.96 R☉ | 0.08–0.6 L☉ | Very weak | 12.1% |
| M | ≤ 3,700 K | red | orange red | ≤ 0.45 M☉ | ≤ 0.7 R☉ | ≤ 0.08 L☉ | Very weak | 76.45% |
The mass, radius, and luminosity listed for each class are appropriate only for stars on the main sequence portion of their lives and so are not appropriate for red giants. A popular mnemonic for remembering the order is "Oh Be A Fine Girl/Guy, Kiss Me" (there are many variants of this mnemonic). The spectral classes O through M are subdivided by Arabic numerals (0–9). For example, A0 denotes the hottest stars in the A class and A9 denotes the coolest ones. The Sun is classified as G2.
| سكي | دريپر | تعليق |
|---|---|---|
| I | A, B, C, D | Hydrogen lines dominant. |
| II | E, F, G, H, I, K, L | |
| III | M | |
| IV | N | لم تظهر في الفهرس. |
| O | Wolf-Rayet spectra with bright lines. | |
| P | Planetary nebulae. | |
| Q | أطياف أخرى. |
الألوان المعتادة والظاهرة
تصنيف يركس الطيفي
A number of different luminosity classes are distinguished:
- 0 hypergiants
- I supergiants
- Ia-0 (hypergiants or extremely luminous supergiants (later addition)), Example: Eta Carinae (spectrum-peculiar)
- Ia (luminous supergiants), Example: Deneb (spectrum is A2Ia)
- Iab (intermediate luminous supergiants)
- Ib (less luminous supergiants), Example: Betelgeuse (spectrum is M2Ib)
- II bright giants
- IIa, Example: β Scuti (HD 173764) (spectrum is G4 IIa)
- IIab Example: HR 8752 (spectrum is G0Iab:)
- IIb, Example: HR 6902 (spectrum is G9 IIb)
- III normal giants
- IIIa, Example: ρ Persei (spectrum is M4 IIIa)
- IIIab Example: δ Reticuli (spectrum is M2 IIIab)
- IIIb, Example: Pollux (spectrum is K2 IIIb)
- IV subgiants
- IVa, Example: ε Reticuli (spectrum is K1-2 IVa-III)
- IVb, Example: HR 672 A (spectrum is G0.5 IVb)
- V main sequence stars (dwarfs)
- Va, Example: AD Leonis (spectrum M4Vae)
- Vab[8]
- Vb, Example: 85 Pegasi A (spectrum G5 Vb)
- "Vz", Example: LH10 : 3102 (spectrum O7 Vz), located in the Large Magellanic Cloud.[9]
- VI subdwarfs (rarely used). Subdwarf are general represented with a prescript of sd or esd (extreme subdwarf) in front of the spectra.
- sd, Example: SSSPM J1930-4311 (spectrum sdM7)
- esd, Example: APMPM J0559-2903 (spectrum esdM7)
- VII white dwarfs (rarely used)
Marginal cases are allowed; for instance a star classified as Ia0-Ia would be a very luminous supergiant, verging on hypergiant. Examples are below. The spectral type of the star is not a factor.
| الرموز الجانبية | مثال | شرح |
|---|---|---|
| - | G2 I-II | The star is between super giant and bright giant. |
| + | O9.5 Ia+ | The star is a hypergiant star. |
| / | M2 IV/V | The star is either a subgiant or a dwarf star. |
الأنواع الطيفية
الرسم التالي يمثل طبقات النجوم بألوان قريبة جداً من تلك الألوان التي تشاهدهم بها العين البشرية. الأحجام النسبية هي من أجل main sequence أو النجوم "القزمة".
Class O
Class B
Class A
Class F
Class G
Class K
Class L
Class T: methane dwarfs
المميزات الطيفية
Additional nomenclature, in the form of lower-case letters, can follow the spectral type to indicate peculiar features of the spectrum.[10]
| Code | المميزات الطيفية للنجوم |
|---|---|
| : | Blending and/or uncertain spectral value |
| … | Undescribed spectral peculiarities exist |
| ! | مميزات خاصة |
| comp | Composite spectrum |
| e | Emission lines present |
| [e] | "Forbidden" emission lines present |
| er | "Reversed" center of emission lines weaker than edges |
| ep | Emission lines with peculiarity |
| eq | Emission lines with P Cygni profile |
| ev | Spectral emission that exhibits variability |
| f | NIII and HeII emission (for element name followed by roman numeral see spectral line) |
| f* | NIV λ4058Å is stronger than the NIII λ4634Å, λ4640Å, & λ4642Å lines[11] |
| f+ | SiIV λ4089Å & λ4116Å are emission in addition to the NIII line[11] |
| (f) | Weak emission lines of He |
| ((f)) | Displays strong HeII absorption accompanied by weak NIII emissions[12] |
| ((f*)) | [9] |
| ((f+)) | [9] |
| h | WR stars with emission lines due to hydrogen.[13] |
| ha | WR stars with hydrogen emissions seen on both absorption and emission.[13] |
| He wk | Weak He lines |
| k | Spectra with interstellar absorption features |
| m | Enhanced metal features |
| (n) | [9] |
| [n] | [9] |
| n | Broad ("nebulous") absorption due to spinning |
| nn | Very broad absorption features due to spinning very fast |
| neb | A nebula's spectrum mixed in |
| p | تميز غير محدد، نجم مميز. |
| pq | Peculiar spectrum, similar to the spectra of novae |
| q | Red & blue shifts line present |
| s | Narrowly "sharp" absorption lines |
| ss | Very narrow lines |
| sh | Shell star features |
| v | Variable spectral feature (also "var") |
| w | Weak lines (also "wl" & "wk") |
| d Del | Type A and F giants with weak calcium H and K lines, as in prototype Delta Delphini |
| d Sct | Type A and F stars with spectra similar to that of short-period variable Delta Scuti |
| Code | If spectrum shows enhanced metal features |
| Ba | Abnormally strong باريوم |
| Ca | Abnormally strong كالسيوم |
| Cr | Abnormally strong كروم |
| Eu | Abnormally strong اوروپيوم |
| He | Abnormally strong هليوم |
| Hg | Abnormally strong زئبق |
| Mn | Abnormally strong منگنيز |
| Si | Abnormally strong سليكون |
| Sr | Abnormally strong سترونتيوم |
| Tc | Abnormally strong تكنتيوم |
| Code | Spectral peculiarities for white dwarfs |
| : | Uncertain assigned classification |
| P | Magnetic white dwarf with detectable polarization |
| E | توجد خطوط إشعاع |
| H | Magnetic white dwarf without detectable polarization |
| V | Variable |
| PEC | توجد مميزات طيفية |
For example, Epsilon Ursae Majoris is listed as spectral type A0pCr, indicating general classification A0 with strong emission lines of the element chromium. There are several common classes of chemically peculiar stars, where the spectral lines of a number of elements appear abnormally strong.
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تصنيف القياس الضوئي
انظر أيضاً
الهامش
المصادر
- ^ أ ب ت ث Tables VII, VIII, Empirical bolometric corrections for the main-sequence, G. M. H. J. Habets and J. R. W. Heinze, Astronomy and Astrophysics Supplement Series 46 (November 1981), pp. 193–237, قالب:Bibcode. التألقات مشتقة من Mbol figures, using Mbol(☉)=4.75.
- ^ The Guinness book of astronomy facts & feats, Patrick Moore, 1992, 0-900424-76-1
- ^ "The Colour of Stars". Australia Telescope Outreach and Education. 2004-12-21. Retrieved 2007-09-26.
{{cite web}}: Check date values in:|date=(help) — يشرح سبب الاختلاف في رؤية اللون. - ^ What color are the stars?, Mitchell Charity. Accessed online March 19, 2008.
- ^ خطأ استشهاد: وسم
<ref>غير صحيح؛ لا نص تم توفيره للمراجع المسماةLeDrew2001 - ^ خطأ استشهاد: وسم
<ref>غير صحيح؛ لا نص تم توفيره للمراجع المسماةdrapera - ^ خطأ استشهاد: وسم
<ref>غير صحيح؛ لا نص تم توفيره للمراجع المسماةdraperb - ^ A Low-Dispersion Luminosity Indicator for Solar-Type Dwarfs, Barry, Don C. 1970
- ^ أ ب ت ث ج Multiwavelength Systematics of OB Spectra, Walborn, N. R., 2008
- ^ SkyTonight: The Spectral Types of Stars
- ^ أ ب Pismis 24-1: The Stellar Upper Mass Limit Preserved, J. Maíz Apellániz et al. 2006
- ^ Early-type stars in the core of the young open cluster Westerlund2, G.Rauw et al. 2006
- ^ أ ب خطأ استشهاد: وسم
<ref>غير صحيح؛ لا نص تم توفيره للمراجع المسماةWR
- مؤمن, عبد الأمير (2006). قاموس دار العلم الفلكي. بيروت، لبنان: دار العلم للملايين.
{{cite book}}: Cite has empty unknown parameter:|طبعة أولى coauthors=(help)
وصلات خارجية
- Libraries of stellar spectra, D. Montes, UCM
- Webfooted Astronomer
- The rate of period change in pulsating DB white dwarf stars, A. H. Corsico, L. G. Althaus, has the DAV, DBV, & DOV explanation.
- The Close DAO+dM Binary RE J0720-318: A Stratified White Dwarf with a Thin H Layer and a Possible Circumbinary Disk DAO type White Dwarf.
- The Spatial Distribution and Kinematics of Cool Metallic Line White Dwarfs, has DAZ and DBZ spectrums
- A K-Band Spectral Atlas of Wolf-Rayet Stars, has WC, WN, and WO spectrums
- Properties of the WO Wolf-Rayet stars, has WO spectrum ranging from WO1 to WO5
- Spectral Types for Hipparcos Catalogue Entries
- [1], has the luminous subclasses.
- Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574, J. Davy Kirkpatrick et al.
| التطور | |
|---|---|
| النشأة | |
| صفوف اللمعان | |
| التصنيف الطيفي | |
| البقايا | |
| نجوم فشلت أو نظرية | |
| التخليق النووي | |
| البنية | |
| الخصائص | |
| أنظمة نجمية | |
| أرصاد متمركزة حول الأرض | |
| القوائم | |
| مقالات متعلقة | |
