热改正

在天文学中，热改正是对天体绝对星等的改正值，以将天体的绝对目视星等转换为热星等（又称全波段星等）。对于大部分辐射出射落在可见光范围之外的恒星，热改正的值将偏大。热改正的统一尺度尚未标准化。

描述

热改正的数学表达式为：

BC=M_{bol}-M_{v}\!\,

下表列出对具有不同光谱类型和分类的一系列恒星的热改正： ^[1] ^[2] ^[3]

光谱型	主序星	巨星	超巨星
O3	-4.3	-4.2	-4.0
G0	-0.10	-0.13	-0.1
G5	-0.14	-0.34	-0.20
00	-0.24	-0.42	-0.38
K5	-0.66	-1.19	-1.00
M0	-1.21	-1.28	-1.3

对于早型星和晚型星，热改正都为偏大的负数。前者是因为早型星表面温度较高，辐射出射的很大一部分是在紫外波段的；后者则是因为晚型星表面温度较低，辐射出射很大一部分在红外波段。对于像我们的太阳这样的恒星，热改正是微不足道的，因为太阳的辐射出射集中在可见光波段。热改正是对天体的绝对星等进行的校正，以将天体的绝对目视星等转换为其热星等。

类似的，热改正可以用于可见光波段之外的其他电磁波段改正为热星等。^[4]例如，对于某些领域内常见的辐射出射集中在红外波段范围内的、表面温度较低的恒星，热改正有时采用一套不同的值以改正红外波段的绝对星等，而非绝对目视星等。

在数学上，这样的改正值可以表示为：

BC_{K}=M_{bol}-M_{k}\!\,

^[5]

其中M _K是K波段的绝对星等， BC _K是K波段的热改正值。 ^[6]

参见

外部链接

https://github.com/casaluca/bolometric-corrections （页面存档备份，存于互联网档案馆） - most up to date tables of bolometric corrections across the HR diagram and interpolation routines in different photometric filters
https://web.archive.org/web/20080312151621/http://www.peripatus.gen.nz/Astronomy/SteMag.html - contains table of bolometric corrections
http://articles.adsabs.harvard.edu//full/1996ApJ...469..355F/0000360.000.html （页面存档备份，存于互联网档案馆） - contains detailed tables of bolometric corrections (note that these second set of tables are consistent with a bolometric magnitude of 4.73 for the Sun and also be aware that there are misprint errors for a few of the figures in the tables)

参考文献

^ Popper, Daniel M. Stellar Masses. Annual Review of Astronomy and Astrophysics. 1980-09-01, 18 (1): 115–164. Bibcode:1980ARA&A..18..115P. ISSN 0066-4146. doi:10.1146/annurev.aa.18.090180.000555.
^ Humphreys, R. M.; McElroy, D. B. The initial mass function for massive stars in the Galaxy and the Magellanic Clouds. The Astrophysical Journal. 1984, 284: 565–577. Bibcode:1984ApJ...284..565H. ISSN 0004-637X. doi:10.1086/162439 （英语）.
^ B., Kaler, James. Stars and their spectra : an introduction to the spectral sequence. Cambridge [Cambridgeshire]: Cambridge University Press. 1989. ISBN 978-0521304948. OCLC 17731797.
^ Bessell, M. S.; et al. Model atmospheres broad-band colors, bolometric corrections and temperature calibrations for O - M stars. Astronomy and Astrophysics. May 1998, 333: 231–250. Bibcode:1998A&A...333..231B.
^ Salaris, Maurizio; et al. Population effects on the red giant clump absolute magnitude: the K band. Monthly Notices of the Royal Astronomical Society. November 2002, 337 (1): 332–340. Bibcode:2002MNRAS.337..332S. arXiv:astro-ph/0208057 . doi:10.1046/j.1365-8711.2002.05917.x. Lower eﬀective temperatures correspond to higher values of $\scriptstyle BC_{K}$ ; since $\scriptstyle M_{K}=M_{bol}-BC_{K}\!\,$ , cooler RC stars tend to be brighter.
^ Buzzoni, A.; et al. Bolometric correction and spectral energy distribution of cool stars in Galactic clusters. Monthly Notices of the Royal Astronomical Society. April 2010, 403 (3): 1592–1610 [23 August 2015]. Bibcode:2010MNRAS.403.1592B. arXiv:1002.1972 . doi:10.1111/j.1365-2966.2009.16223.x.

[1] Popper, Daniel M. Stellar Masses. Annual Review of Astronomy and Astrophysics. 1980-09-01, 18 (1): 115–164. Bibcode:1980ARA&A..18..115P. ISSN 0066-4146. doi:10.1146/annurev.aa.18.090180.000555.

[2] Humphreys, R. M.; McElroy, D. B. The initial mass function for massive stars in the Galaxy and the Magellanic Clouds. The Astrophysical Journal. 1984, 284: 565–577. Bibcode:1984ApJ...284..565H. ISSN 0004-637X. doi:10.1086/162439 （英语）.

[3] B., Kaler, James. Stars and their spectra : an introduction to the spectral sequence. Cambridge [Cambridgeshire]: Cambridge University Press. 1989. ISBN 978-0521304948. OCLC 17731797.

[4] Bessell, M. S.; et al. Model atmospheres broad-band colors, bolometric corrections and temperature calibrations for O - M stars. Astronomy and Astrophysics. May 1998, 333: 231–250. Bibcode:1998A&A...333..231B.

[nonredclumpSalaris2002-5] Salaris, Maurizio; et al. Population effects on the red giant clump absolute magnitude: the K band. Monthly Notices of the Royal Astronomical Society. November 2002, 337 (1): 332–340. Bibcode:2002MNRAS.337..332S. arXiv:astro-ph/0208057 . doi:10.1046/j.1365-8711.2002.05917.x. Lower eﬀective temperatures correspond to higher values of $\scriptstyle BC_{K}$ ; since $\scriptstyle M_{K}=M_{bol}-BC_{K}\!\,$ , cooler RC stars tend to be brighter.

[nonstandardphotography2010-6] Buzzoni, A.; et al. Bolometric correction and spectral energy distribution of cool stars in Galactic clusters. Monthly Notices of the Royal Astronomical Society. April 2010, 403 (3): 1592–1610 [23 August 2015]. Bibcode:2010MNRAS.403.1592B. arXiv:1002.1972 . doi:10.1111/j.1365-2966.2009.16223.x.

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