天苑十一

天苑十一（波江座τ4）是位于波江座的双星系统，其视星等为3.65。

天苑十一

觀測資料 曆元 J2000.0 (ICRS)
星座	波江座
星官
赤經	03h 19m 31.00224s[1]
赤緯	−21° 45′ 28.3049″[1]
視星等（V）	3.65[2]
特性
光谱分类	M3/4 III[3]
U−B 色指数	+1.79[2]
B−V 色指数	+1.61[2]
变星类型	Lb[4]
天体测定
徑向速度 (Rv)	7001417000000000000♠+41.7±0.7[5] km/s
自行 (μ)	赤经：+51.89[1] mas/yr 赤纬：+32.92[1] mas/yr
视差 (π)	10.71 ± 0.54[1] mas
距离	300 ± 20 ly (93 ± 5 pc)
绝对星等 (MV)	−0.79[6]
詳細資料
質量	7000180000000000000♠1.8±0.3[7] M☉
半徑	106[8] R☉
亮度	1,537[9] L☉
溫度	3,712[7] K
其他命名
τ4 Eridani, τ4 Eri, 16 Eridani, BD-22° 584, HD 20720, HIP 15474, HR 1003, SAO 168460.[10]
參考資料庫
SIMBAD	资料

参考文献

1. van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.
2. Mermilliod, J.-C., Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, 1986, Bibcode:1986EgUBV........0M.
3. Houk, N.; Smith-Moore, M., Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 4, 1988, Bibcode:1988MSS...C04....0H.
4. Ruban, E. V.; et al, Spectrophotometric observations of variable stars, Astronomy Letters, September 2006, 32 (9): 604–607, Bibcode:2006AstL...32..604R, doi:10.1134/S1063773706090052.
5. Gontcharov, G. A., Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system, Astronomy Letters, November 2006, 32 (11): 759–771, Bibcode:2006AstL...32..759G, arXiv:1606.08053 , doi:10.1134/S1063773706110065.
6. Cardini, D., Mg II chromospheric radiative loss rates in cool active and quiet stars, Astronomy and Astrophysics, January 2005, 430: 303−311, Bibcode:2005A&A...430..303C, arXiv:astro-ph/0409683 , doi:10.1051/0004-6361:20041440.
7. Halabi, Ghina M.; Eid, Mounib El. Exploring masses and CNO surface abundances of red giant stars. Monthly Notices of the Royal Astronomical Society. 2015, 451 (3): 2957. Bibcode:2015MNRAS.451.2957H. arXiv:1507.01517 . doi:10.1093/mnras/stv1141.
8. Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3, Birkhäuser, 2006 [2018-02-23], ISBN 3-540-29692-1, （原始内容存档于2019-05-20）. The radius (R_*) is given by:

   ${\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(93\cdot 10.58\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 212\cdot R_{\bigodot }\end{aligned}}}$

9. McDonald, I.; et al, Fundamental Parameters and Infrared Excesses of Hipparcos Stars, Monthly Notices of the Royal Astronomical Society, 2012, 427 (1): 343–57, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037 , doi:10.1111/j.1365-2966.2012.21873.x.
10. tau04 Eri. SIMBAD. 斯特拉斯堡天文資料中心. [2016-10-13].