# B3 Hydrae

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For other stars with this Bayer designation, see [b Hydrae](/source/B_Hydrae).

Multiple star system in the constellation Hydra

b3 Hydrae Observation data Epoch J2000.0 Equinox J2000.0 Constellation Hydra[1] Right ascension 10h 53m 29.532s[2] Declination −20° 08′ 19.43″[2] Apparent magnitude (V) 5.24[3] Characteristics Evolutionary stage main sequence[2] Spectral type F5V[3] U−B color index +0.06[3] B−V color index +0.47[3] Astrometry Radial velocity (Rv) −4.08±0.12[2] km/s Proper motion (μ) RA: +80.915[2] mas/yr Dec.: −238.566[2] mas/yr Parallax (π) 33.2327±0.1234 mas[2] Distance 98.1 ± 0.4 ly (30.1 ± 0.1 pc) Absolute magnitude (MV) +2.79[1] Details Mass 1.48[4] M☉ Radius 1.93[5] R☉ Luminosity 6.02[5] L☉ Surface gravity (log g) 3.99[5] cgs Temperature 6,505[5] K Metallicity [Fe/H] +0.09[4] dex Rotation 27.1 days[6] Rotational velocity (v sin i) 6.0[7] km/s Age 2.27[4] Gyr Other designations b3 Hya, 6 Crt, HD 94388, HIP 53252, HR 4521, SAO 156301, PPM 258261, CCDM J10534-2009A, WDS J10535-2008A[8] Database references SIMBAD data

**b3 Hydrae** (**6 Crateris**) is a star in the constellation [Hydra](/source/Hydra_(constellation)) at a distance of approximately 98 [light-years](/source/Light-year) (about 30 [parsecs](/source/Parsecs)) from the [Sun](/source/Sun). It has three [optical companions](/source/Optical_double), which are background stars located much farther away.

## Description

b3 Hydrae (WDS J10535-2008A) is a yellow-white [main sequence](/source/Main_sequence) star with the [spectral type](/source/Spectral_class) of F5V. The [apparent magnitude](/source/Apparent_magnitude) of the star is +5.232. It has about 1.5 [M☉](/source/Solar_mass), its radius is about 1.9 [*R*☉](/source/Solar_radius) and the luminosity is about 6.0 [L☉](/source/Solar_luminosity). The age of the star is determined to be about 1.647 billion years.[4] The [effective temperature](/source/Effective_temperature) is about 6,505 [K](/source/Kelvin).

## Optical companions

### BD−19 3124

The secondary (BD−19 3124) is a yellow main sequence star of spectral type G5.[9] The apparent magnitude of the star is +9.6.[10] The mass is about 1.492 ± 0.001 [M☉](/source/Solar_mass)[11], the radius is about 2.071 ± 0.008 [*R*☉](/source/Solar_radius)[11], the luminosity is about 6.946 ± 0.001 [L☉](/source/Solar_luminosity)[11]. The effective temperature is about 6,566±1 K[11]. It is 119.6 [arcseconds](/source/Arcsecond) away from b3 Hydrae[12] and about 774 [light-years](/source/Light-year) (237 [parsecs](/source/Parsec)) away from the Solar System.[11]

### UCAC2 23866861

The third component (UCAC2 23866861) is a [yellow dwarf](/source/G-type_main-sequence_stars) of spectral type G.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] The apparent magnitude of the star is +11.6.[13] The mass is about 0.989 ± 0.001 [M☉](/source/Solar_mass)[14], the radius is about 1.315 ± 0.002 [*R*☉](/source/Solar_radius)[14], the luminosity is about 1.662 ± 0.001 [L☉](/source/Solar_luminosity)[14]. The effective temperature is about 5,761±4 K[14]. It is separated from BD−19 3124 by 13.7 arc seconds[12] and is about 850 [light-years](/source/Light-year) (260 [parsecs](/source/Parsec)) away from the Solar System.[14]

### UCAC2 23866855

The fourth component (UCAC2 23866855) is a yellow-white star of spectral type F.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] The apparent magnitude of the star is +13.5.[15] The mass is about 1.332 ± 0.001 [M☉](/source/Solar_mass)[16] the radius is about 1.829 ± 0.005 [*R*☉](/source/Solar_radius)[16] the luminosity is about 4.356 ± 0.001 [L☉](/source/Solar_luminosity)[16] the effective temperature is about 6,236±1 K[16]. It is located 40.5 arc seconds away from BD−19 3124[12] and is about 3,820 [light-years](/source/Light-year) (1,170 [parsecs](/source/Parsec)) away from the Solar System.[16]

## References

1. ^ [***a***](#cite_ref-xhipa_1-0) [***b***](#cite_ref-xhipa_1-1) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *[Astronomy Letters](/source/Astronomy_Letters)*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=53252&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-dr3a_2-0) [***b***](#cite_ref-dr3a_2-1) [***c***](#cite_ref-dr3a_2-2) [***d***](#cite_ref-dr3a_2-3) [***e***](#cite_ref-dr3a_2-4) [***f***](#cite_ref-dr3a_2-5) [***g***](#cite_ref-dr3a_2-6) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D3551002857809958400%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-DATA_3-0) [***b***](#cite_ref-DATA_3-1) [***c***](#cite_ref-DATA_3-2) [***d***](#cite_ref-DATA_3-3) ["VizieR Detailed Page"](https://web.archive.org/web/20160304210307/http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=5050&-corr=PK=HR&-out.max=9999&HR=4251). Archived from [the original](http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=5050&-corr=PK=HR&-out.max=9999&HR=4251) on 2016-03-04. Retrieved 2012-07-13.

1. ^ [***a***](#cite_ref-ag2018_4-0) [***b***](#cite_ref-ag2018_4-1) [***c***](#cite_ref-ag2018_4-2) [***d***](#cite_ref-ag2018_4-3) Aguilera-Gómez, Claudia; Ramírez, Iván; Chanamé, Julio (2018). "Lithium abundance patterns of late-F stars: An in-depth analysis of the lithium desert". *Astronomy and Astrophysics*. **614**: A55. [arXiv](/source/ArXiv_(identifier)):[1803.05922](https://arxiv.org/abs/1803.05922). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...614A..55A](https://ui.adsabs.harvard.edu/abs/2018A&A...614A..55A). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201732209](https://doi.org/10.1051%2F0004-6361%2F201732209).

1. ^ [***a***](#cite_ref-tic_5-0) [***b***](#cite_ref-tic_5-1) [***c***](#cite_ref-tic_5-2) [***d***](#cite_ref-tic_5-3) Stassun, Keivan G.; et al. (2019). ["The Revised TESS Input Catalog and Candidate Target List"](https://doi.org/10.3847%2F1538-3881%2Fab3467). *The Astronomical Journal*. **158** (4): 138. [arXiv](/source/ArXiv_(identifier)):[1905.10694](https://arxiv.org/abs/1905.10694). [Bibcode](/source/Bibcode_(identifier)):[2019AJ....158..138S](https://ui.adsabs.harvard.edu/abs/2019AJ....158..138S). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/ab3467](https://doi.org/10.3847%2F1538-3881%2Fab3467).

1. **[^](#cite_ref-oelkers2025_6-0)** Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). ["Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey"](https://doi.org/10.3847%2F1538-3881%2Faa9bf4). *The Astronomical Journal*. **155** (1): 39. [arXiv](/source/ArXiv_(identifier)):[1711.03608](https://arxiv.org/abs/1711.03608). [Bibcode](/source/Bibcode_(identifier)):[2018AJ....155...39O](https://ui.adsabs.harvard.edu/abs/2018AJ....155...39O). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/aa9bf4](https://doi.org/10.3847%2F1538-3881%2Faa9bf4).

1. **[^](#cite_ref-reiners2003_7-0)** Reiners, A.; Schmitt, J. H. M. M. (2003). "Rotation and differential rotation in field F- and G-type stars". *Astronomy and Astrophysics*. **398** (2): 647. [Bibcode](/source/Bibcode_(identifier)):[2003A&A...398..647R](https://ui.adsabs.harvard.edu/abs/2003A&A...398..647R). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20021642](https://doi.org/10.1051%2F0004-6361%3A20021642).

1. **[^](#cite_ref-SIMBAD_8-0)** ["6 Crateris"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=6+Crateris). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2025-09-14.

1. **[^](#cite_ref-ma2023_9-0)** Maíz Apellániz, J.; Holgado, G.; Pantaleoni González, M.; Caballero, J. A. (2023). "Stellar variability in Gaia DR3. I. Three-band photometric dispersions for 145 million sources". *Astronomy and Astrophysics*. **677**: A137. [arXiv](/source/ArXiv_(identifier)):[2304.14249](https://arxiv.org/abs/2304.14249). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...677A.137M](https://ui.adsabs.harvard.edu/abs/2023A&A...677A.137M). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202346759](https://doi.org/10.1051%2F0004-6361%2F202346759).

1. **[^](#cite_ref-tycho2_10-0)** Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". *Astronomy and Astrophysics*. **355**. [Bibcode](/source/Bibcode_(identifier)):[2000A&A...355L..27H](https://ui.adsabs.harvard.edu/abs/2000A&A...355L..27H).

1. ^ [***a***](#cite_ref-dr3b_11-0) [***b***](#cite_ref-dr3b_11-1) [***c***](#cite_ref-dr3b_11-2) [***d***](#cite_ref-dr3b_11-3) [***e***](#cite_ref-dr3b_11-4) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D3551001345981136384%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-wds_12-0) [***b***](#cite_ref-wds_12-1) [***c***](#cite_ref-wds_12-2) Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". *The Astronomical Journal*. **122** (6): 3466. [Bibcode](/source/Bibcode_(identifier)):[2001AJ....122.3466M](https://ui.adsabs.harvard.edu/abs/2001AJ....122.3466M). [doi](/source/Doi_(identifier)):[10.1086/323920](https://doi.org/10.1086%2F323920).

1. **[^](#cite_ref-UCAC4-RPM_13-0)** Nascimbeni, V.; Piotto, G.; Ortolani, S.; Giuffrida, G.; Marrese, P. M.; Magrin, D.; Ragazzoni, R.; Pagano, I.; Rauer, H.; Cabrera, J.; Pollacco, D.; Heras, A. M.; Deleuil, M.; Gizon, L.; Granata, V. (2016). ["An all-sky catalogue of solar-type dwarfs for exoplanetary transit surveys"](https://doi.org/10.1093%2Fmnras%2Fstw2313). *Monthly Notices of the Royal Astronomical Society*. **463** (4): 4210. [arXiv](/source/ArXiv_(identifier)):[1609.03037](https://arxiv.org/abs/1609.03037). [Bibcode](/source/Bibcode_(identifier)):[2016MNRAS.463.4210N](https://ui.adsabs.harvard.edu/abs/2016MNRAS.463.4210N). [doi](/source/Doi_(identifier)):[10.1093/mnras/stw2313](https://doi.org/10.1093%2Fmnras%2Fstw2313).

1. ^ [***a***](#cite_ref-dr3c_14-0) [***b***](#cite_ref-dr3c_14-1) [***c***](#cite_ref-dr3c_14-2) [***d***](#cite_ref-dr3c_14-3) [***e***](#cite_ref-dr3c_14-4) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D3551001345981136256%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. **[^](#cite_ref-ucac4_15-0)** Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". *Vizier Online Data Catalog*. [Bibcode](/source/Bibcode_(identifier)):[2012yCat.1322....0Z](https://ui.adsabs.harvard.edu/abs/2012yCat.1322....0Z).

1. ^ [***a***](#cite_ref-dr3d_16-0) [***b***](#cite_ref-dr3d_16-1) [***c***](#cite_ref-dr3d_16-2) [***d***](#cite_ref-dr3d_16-3) [***e***](#cite_ref-dr3d_16-4) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D3551001414700613248%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

v t e Constellation of Hydra List of stars in Hydra Hydra in Chinese astronomy Stars Bayer α (Alphard) β γ (Naga) δ ε (Ashlesha) ζ η θ ι (Ukdah) κ λ μ ν ξ ο π ρ σ (Minchir) τ1 τ2 υ1 (Zhang) υ2 φ1 φ2 φ3 χ1 χ2 ψ ω b1 b3 C F Flamsteed 1 2 3 6 (a) 9 10 12 (D) 14 15 17 19 20 21 23 24 25 26 27 (P) 28 29 33 (A) 34 37 44 47 48 50 51 (k) 52 (l) 54 (m) 55 56 57 58 (Solitaire) 59 60 10 Crt 17 Crt 20 Crt 2 Sex Variable R U V W TW EX HS KU LQ V361 V419 V421 V478 V484 HR 3378 3538 3749 (G) 3750 3858 (I) 3862 3919 3923 (Felis) 4162 4328 4339 (β Ant) 4445 5265 HD 72659 74156 82943 86226 86264 90156 (γ Ant) Other 2MASS 1114−2618 ESO 439-26 Gliese 328 Gliese 357 Gliese 433 Gliese 453 GJ 3634 HAT-P-30 HE 1256−2738 HE 1327−2326 LHS 2065 LHS 3003 LTT 3780 SDSS J090745.0+024507 WASP-25 WASP-36 WASP-84 WASP-166 (Filetdor) WISE 0855−0714 WISEA J1141−3326 Exoplanets Gliese 357 d HD 72659 b HD 74156 b c HD 82943 b c HD 86226 b HD 86264 b TW Hydrae b (unconfirmed) WASP-193b Star clusters Messier 48 Messier 68 NGC 5694 Price-Whelan 1 Nebulae Abell 33 Abell 35 NGC 3242 Southern Owl Nebula Galaxies Messier 83 NGC 2617 2642 2697 2708 2758 2835 2848 2865 2890 2935 2936 2937 2960 2962 2986 2992 3030 3052 3054 3081 3109 3124 3200 3285 3285B 3290 3305 3307 3308 3309 3311 3312 3313 3314 3315 3316 3336 3369 3383 3393 3402 3463 3464 3585 3621 3673 3717 3904 3923 3936 4980 4993 5042 5061 5078 5085 5101 5135 5260 5264 5495 5626 Other 3C 196.1 AM 1316−241 Arp 7 CTQ 327 ESO 510-G13 GAMA202627 GLEAM J0917−0012 Hydra A IC 535 MRC 1138−262 Peekaboo Galaxy PKS 1151−348 RX J0911.4+0551 SDSS J0841+0101 TN J0924−2201 Tololo 1247−232 ZwCl 1693 BCG Galaxy clusters Abell 754 Abell 3411 Abell 3412 Bullet Group Hickson 40 Astronomical events GW170817 Category

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Adapted from the Wikipedia article [B3 Hydrae](https://en.wikipedia.org/wiki/B3_Hydrae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/B3_Hydrae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.