天苑十一

**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
赤緯	−21° 45′ 28.3049″
視星等（V）	3.65
特性
光譜分類	M3/4 III
U−B 色指數	+1.79
B−V 色指數	+1.61
變星類型	Lb
天體測定
徑向速度 (Rv)	+41.7±0.7 km/s
自行 (μ)	赤經：+51.89 mas/yr ; 赤緯：+32.92 mas/yr
視差 (π)	10.71 ± 0.54 mas
距離	300 ± 20 ly ; (93 ± 5 pc)
絕對星等 (MV)	−0.79
詳細資料
質量	1.8±0.3 M☉
半徑	106 R☉
亮度	1,537 L☉
溫度	3,712 K
其他命名
	τ4 Eridani, τ4 Eri, 16 Eridani, BD-22° 584, HD 20720, HIP 15474, HR 1003, SAO 168460.
參考資料庫
SIMBAD	資料

天苑十一（波江座τ4）是位於波江座的雙星系統，其視星等為3.65。

參考文獻

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 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.
^ ^2.0 ^2.1 ^2.2 Mermilliod, J.-C., Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, 1986, Bibcode:1986EgUBV........0M.
^ Houk, N.; Smith-Moore, M., Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 4, 1988, Bibcode:1988MSS...C04....0H.
^ 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.
^ 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.
^ 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.
^ ^7.0 ^7.1 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.
^ Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3, Birkhäuser, 2006 [2018-02-23], ISBN 3-540-29692-1, （原始內容存檔於2019-05-20）. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(93\cdot 10.58\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 212\cdot R_{\bigodot }\end{aligned}}$
^ 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.
^ tau04 Eri. SIMBAD. 斯特拉斯堡天文資料中心. [2016-10-13].

[vanLeeuwen2007-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 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.

[Mermilliod1986-2] 2.0 ^2.1 ^2.2 Mermilliod, J.-C., Compilation of Eggen's UBV data, transformed to UBV (unpublished), SIMBAD, 1986, Bibcode:1986EgUBV........0M.

[houk1988-3] Houk, N.; Smith-Moore, M., Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 4, 1988, Bibcode:1988MSS...C04....0H.

[Ruban2006-4] 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.

[Gontcharov2006-5] 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.

[Cardini2005-6] 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.

[halabi2015-7] 7.0 ^7.1 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.

[lang2006-8] Lang, Kenneth R., Astrophysical formulae, Astronomy and astrophysics library 1 3, Birkhäuser, 2006 [2018-02-23], ISBN 3-540-29692-1, （原始內容存檔於2019-05-20）. The radius (R_*) is given by:
${\begin{aligned}2\cdot R_{*}&={\frac {(93\cdot 10.58\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 212\cdot R_{\bigodot }\end{aligned}}$

[Mcdonald2012-9] 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.

[SIMBAD-10] tau04 Eri. SIMBAD. 斯特拉斯堡天文資料中心. [2016-10-13].

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觀測資料曆元 J2000.0 (ICRS)
星座	波江座
星官
赤經	03^h 19^m 31.00224^s^[1]
赤緯	−21° 45′ 28.3049″^[1]
視星等（V）	3.65^[2]
特性
光譜分類	M3/4 III^[3]
U−B 色指數	+1.79^[2]
B−V 色指數	+1.61^[2]
變星類型	Lb^[4]
天體測定

徑向速度 (R_v)	7001417000000000000♠+41.7±0.7^[5] km/s
自行 (μ)	赤經：+51.89^[1] mas/yr 赤緯：+32.92^[1] mas/yr
視差 (π)	10.71 ± 0.54^[1] mas
距離	300 ± 20 ly (93 ± 5 pc)
絕對星等 (M_V)	−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	資料