This web page is a collection of spectra for stars in eclipsing binary systems for which the effective temperature has been measured directly from the its angular diameter and bolometric flux, i.e.
\[T_{\rm eff} = (4F_{\rm bol} \theta/\sigma_{\rm SB})^{1/4},\]
where \(\sigma_{\rm SB}\) is the Stefan-Boltzmann constant and \(\theta = 2\,R_{\star}/d\) is the angular diameter of a star of radius \(R_{\star}\) at distance \(d\). The full method is described in Miller, Maxted and Smalley, 2020.
N.B. these are spectra of one star in the binary system with zero or negligible contribution from the companion star.
In the table below, the 2MASS identifier gives the RA and Dec of the stars and is a link to the SIMBAD page.
| Name | 2MASS | Teff [K] | log g | [Fe/H] | Source | Spectra | |
|---|---|---|---|---|---|---|---|
| AI Phe | A | J01093419-4615560 | 6199 ± 46 | 4.002 ± 0.001 | -0.16 | Maxted et al., 2026 | AI_Phe.zip |
| B | 5094 ± 36 | 3.598 ± 0.001 | -0.08 | ||||
| CPD-54 810 | A | J05175294-5406053 | 6462 ± 43 | 3.984 ± 0.001 | 0.0 | Miller et al., 2022 | CPD-54_810.zip |
| B | 6331 ± 43 | 4.330 ± 0.003 | |||||
| EBLM_J0113+31 | A | J01135129+3149097 | 6124 ± 50 | 4.148 ± 0.006 | -0.3 | Maxted et al., 2022 | EBLM_J0113+31_A.zip |
| HD_22064 | A | J03332757+0007107 | 6763 ± 39 | 4.184 ± 0.006 | -0.05 | Maxted et al., 2023 | HD_22064_A.zip |
| BEBOP-3 | A | J07233671+7907569 | 6065 ± 44 | 4.190 ± 0.004 | -0.02 | Maxted et al., 2025 | BEBOP_3_A.zip |
| EBLM J0608-59 | A | J06083197-5932280 | 6031 ± 46 | 4.24 ± 0.01 | 0.01 | Maxted et al., 2024 | EBLM_J0608-59_A.zip |
| CD-27_2812 | A | J06125965-2752493 | 6197 ± 55 | 4.1 ± 0.002 | 0.15 | Adshead et al., 2026 | CD-27_2812.zip |
| CD-31_3271 | A | J06244892-3151522 | 6064 ± 62 | 4.431 ± 0.001 | 0.12 | Hahlin et al. | CD-31_3271.zip |
| HD_4875 | A | J00503998-1830213 | 6013 ± 25 | 4.260 ± 0.004 | 0.12 | Hahlin et al. | HD_4875.zip |
| HD_287990 | A | J05310419+0111156 | 6486 ± 55 | 4.127 ± 0.008 | 0.1 | Hahlin et al. | HD_287990.zip |
| TYC_8547-22-1 | A | J06365893-5827366 | 5995 ± 30 | 4.119 ± 0.001 | 0.22 | Hahlin et al. | TYC_8547-22-1.zip |
| BD-08_1175 | A | J05365582-0847576 | 6038 ± 34 | 4.259 ± 0.001 | -0.32 | Hahlin et al. | BD-08_1175.zip |
Individual spectra for a star in an eclipsing binary have be obtained by one of the following methods …
Spectrum of the larger star in a binary obtained during a total eclipse when the smaller companion is completely hidden.
EBLM systems are eclipsing binaries where the F-/G-type primary star has a very low-mass M-dwarf companions. The flux from the companion in the optical spectrum is negligible (\(\approx 0.2\)% or less).
Spectra where the flux contribution from the fainter star has been removed using synthetic spectra. This works well for systems where the flux ratio is \(\approx 1\)% or less, e.g. near-infrared spectra of EBLM systems.
Extraction of the individual spectra from a set of combined spectra using the spectral disentangling method by Simon & Sturm (1994) (or some other method).
The disentagled spectra are computed so that their sum after the appropriate radial velocity shifts have been applied gives the best least-squares fit to the observed spectra, and so that the flux ratio matches the value expected based on the light curve analysis. Errors in normalisation for the input spectra result in some parts of the disentangled spectrum not having the correct flux ratio. This can be seen as one spectrum being too high in some wavelength regions and the other spectrum being too low in the same wavelength regions. This problem is worse for noisy echelle spectra near the ends of the echelle orders.
If you have a better estimate of what the flux ratio, \(R\), should be in the some part of the spectrum then you should proceed as follows
Calculate the constant \(C\) such that \(R = (f_2 + C)/(f_1 - C)\), so \(C = (R\times f_1 - f_2) /(1+R)\)