# Pi Boötis

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Star in the constellation Boötes

Pi Boötis Location of π Boötis (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Boötes[1] Right ascension 14h 40m 43.559s[2] Declination +16° 25′ 05.98″[2] Apparent magnitude (V) 4.49[1] (4.893 + 5.761)[3] Characteristics Spectral type B9 IIIp (MnHgSi) + A6 V[4] U−B color index −0.31[5] B−V color index −0.002±0.010[1] R−I color index −0.02[citation needed] Astrometry Radial velocity (Rv) −1.1±0.8[6] km/s Proper motion (μ) RA: +13.922 mas/yr[2] Dec.: +15.566 mas/yr[2] Parallax (π) 10.3357±0.1199 mas[2] Distance 316 ± 4 ly (97 ± 1 pc) Absolute magnitude (MV) –0.39[7] Details π1 Boo Mass 3.49±0.14[7] M☉ Radius 3.2±0.4[7] R☉ Luminosity 214[7] L☉ Surface gravity (log g) 3.99±0.18[8] cgs Temperature 12,052±456[8] K Metallicity [Fe/H] +0.18±0.17[8] dex Rotational velocity (v sin i) 14.0[9] km/s π2 Boo Surface gravity (log g) 3.60±0.01[10] cgs Temperature 7504+21 −17[10] K Metallicity [Fe/H] 0.580[10] dex Rotational velocity (v sin i) 144[11] km/s Other designations π Boo, 29 Boötis, BD+17°2768, HIP 71762, ADS 9338[12] π1 Boötis: HD 129174, HR 5475, SAO 101138 π2 Boötis: HD 129175, HR 5476, SAO 101139 Database references SIMBAD π1 Boo π2 Boo

**Pi Boötis** is a candidate [triple star](/source/Triple_star)[13] system in the northern [constellation](/source/Constellation) of [Boötes](/source/Bo%C3%B6tes). Its name is a [Bayer designation](/source/Bayer_designation) that is [Latinized](/source/Latinisation_of_names) from **π Boötis**, and abbreviated Pi Boo or π Boo. This system is visible to the [naked eye](/source/Naked_eye) as a point of light with a combined [apparent visual magnitude](/source/Apparent_visual_magnitude) of 4.50.[14] Based upon an annual [parallax shift](/source/Stellar_parallax) of 10.67 [mas](/source/Milliarcsecond)[2] as seen from Earth, it is located roughly 316 [light years](/source/Light_year) from the [Sun](/source/Sun).

The brighter primary, component π1 Boötis, has a visual magnitude of 4.89[3] and a [stellar classification](/source/Stellar_classification) of B9 IIIp (MnHgSi),[4] which suggests it is an [evolved](/source/Stellar_evolution) blue-white hued [B-type](/source/B-type_star) [giant star](/source/Giant_star). It is a [chemically peculiar star](/source/Chemically_peculiar_star) of the [HgMn type](/source/HgMn_star),[9] with a [spectrum](/source/Stellar_spectrum) that displays anomalous overabundances of mercury, manganese, and silicon.[4] This component is most likely a single-lined [spectroscopic binary](/source/Spectroscopic_binary) with an unknown companion.[13]

Its magnitude 5.76[3] visible companion, π2 Boötis, is a white-hued [A-type main-sequence star](/source/A-type_main-sequence_star) with a class of A6 V.[4] It is spinning rapidly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 144 km/s.[11] As of 2010, the pair were separated by 5.537±0.003 [arcseconds](/source/Arcsecond) on the sky along a [position angle](/source/Position_angle) of 110.5°±0.5°. This corresponds to a [projected separation](/source/Projected_separation) of 538.6±47.7 [AU](/source/Astronomical_Unit). The odds that is a mere chance alignment is 0.85%.[13]

Pi Boötis has the [Chinese traditional star name](/source/Traditional_Chinese_star_names) 左攝提二 (Zuǒ shè tí èr).

## References

1. ^ [***a***](#cite_ref-Anderson_Francis_2012_1-0) [***b***](#cite_ref-Anderson_Francis_2012_1-1) [***c***](#cite_ref-Anderson_Francis_2012_1-2) 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=71762&-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-GaiaDR3_2-0) [***b***](#cite_ref-GaiaDR3_2-1) [***c***](#cite_ref-GaiaDR3_2-2) [***d***](#cite_ref-GaiaDR3_2-3) [***e***](#cite_ref-GaiaDR3_2-4) 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%3D1234645287617291520%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Hog2000_3-0) [***b***](#cite_ref-Hog2000_3-1) [***c***](#cite_ref-Hog2000_3-2) Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", *Astronomy and Astrophysics*, **355**: L27, [Bibcode](/source/Bibcode_(identifier)):[2000A&A...355L..27H](https://ui.adsabs.harvard.edu/abs/2000A&A...355L..27H), [doi](/source/Doi_(identifier)):[10.1888/0333750888/2862](https://doi.org/10.1888%2F0333750888%2F2862).

1. ^ [***a***](#cite_ref-Abt1984_4-0) [***b***](#cite_ref-Abt1984_4-1) [***c***](#cite_ref-Abt1984_4-2) [***d***](#cite_ref-Abt1984_4-3) Abt, H. A.; Cardona, O. (January 1, 1984), "The nature of the visual companions of Ap and Am stars", *Astrophysical Journal, Part 1*, **276**: 266–269, [Bibcode](/source/Bibcode_(identifier)):[1984ApJ...276..266A](https://ui.adsabs.harvard.edu/abs/1984ApJ...276..266A), [doi](/source/Doi_(identifier)):[10.1086/161610](https://doi.org/10.1086%2F161610).

1. **[^](#cite_ref-Nicolet1978_5-0)** Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", *Astronomy and Astrophysics Supplement Series*, **34**: 1–49, [Bibcode](/source/Bibcode_(identifier)):[1978A&AS...34....1N](https://ui.adsabs.harvard.edu/abs/1978A&AS...34....1N).

1. **[^](#cite_ref-Gontcharov2006_6-0)** Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", *Astronomy Letters*, **32** (11): 759–771, [arXiv](/source/ArXiv_(identifier)):[1606.08053](https://arxiv.org/abs/1606.08053), [Bibcode](/source/Bibcode_(identifier)):[2006AstL...32..759G](https://ui.adsabs.harvard.edu/abs/2006AstL...32..759G), [doi](/source/Doi_(identifier)):[10.1134/S1063773706110065](https://doi.org/10.1134%2FS1063773706110065), [S2CID](/source/S2CID_(identifier)) [119231169](https://api.semanticscholar.org/CorpusID:119231169).

1. ^ [***a***](#cite_ref-North1998_7-0) [***b***](#cite_ref-North1998_7-1) [***c***](#cite_ref-North1998_7-2) [***d***](#cite_ref-North1998_7-3) North, P. (June 1998), "Do SI stars undergo any rotational braking?", *Astronomy and Astrophysics*, **334**: 181–187, [arXiv](/source/ArXiv_(identifier)):[astro-ph/9802286](https://arxiv.org/abs/astro-ph/9802286), [Bibcode](/source/Bibcode_(identifier)):[1998A&A...334..181N](https://ui.adsabs.harvard.edu/abs/1998A&A...334..181N).

1. ^ [***a***](#cite_ref-prugniel2011_8-0) [***b***](#cite_ref-prugniel2011_8-1) [***c***](#cite_ref-prugniel2011_8-2) Prugniel, P.; et al. (2011), "The atmospheric parameters and spectral interpolator for the MILES stars", *Astronomy & Astrophysics*, **531**: A165, [arXiv](/source/ArXiv_(identifier)):[1104.4952](https://arxiv.org/abs/1104.4952), [Bibcode](/source/Bibcode_(identifier)):[2011A&A...531A.165P](https://ui.adsabs.harvard.edu/abs/2011A&A...531A.165P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201116769](https://doi.org/10.1051%2F0004-6361%2F201116769), [S2CID](/source/S2CID_(identifier)) [54940439](https://api.semanticscholar.org/CorpusID:54940439).

1. ^ [***a***](#cite_ref-Ghazaryan2016_9-0) [***b***](#cite_ref-Ghazaryan2016_9-1) Ghazaryan, S.; Alecian, G. (August 2016), "Statistical analysis from recent abundance determinations in HgMn stars", *Monthly Notices of the Royal Astronomical Society*, **460** (2): 1912–1922, [Bibcode](/source/Bibcode_(identifier)):[2016MNRAS.460.1912G](https://ui.adsabs.harvard.edu/abs/2016MNRAS.460.1912G), [doi](/source/Doi_(identifier)):[10.1093/mnras/stw911](https://doi.org/10.1093%2Fmnras%2Fstw911)

1. ^ [***a***](#cite_ref-Royer_et_al_2024_10-0) [***b***](#cite_ref-Royer_et_al_2024_10-1) [***c***](#cite_ref-Royer_et_al_2024_10-2) Royer, P.; et al. (January 2024), "MELCHIORS. The Mercator Library of High Resolution Stellar Spectroscopy", *Astronomy & Astrophysics*, **681**, id. A107, [arXiv](/source/ArXiv_(identifier)):[2311.02705](https://arxiv.org/abs/2311.02705), [Bibcode](/source/Bibcode_(identifier)):[2024A&A...681A.107R](https://ui.adsabs.harvard.edu/abs/2024A&A...681A.107R), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202346847](https://doi.org/10.1051%2F0004-6361%2F202346847).

1. ^ [***a***](#cite_ref-Royer_et_al_2002_11-0) [***b***](#cite_ref-Royer_et_al_2002_11-1) Royer, F.; et al. (May 2002), "Rotational velocities of A-type stars II. Measurement of vsini in the northern hemisphere", *Astronomy & Astrophysics*, **393**: 897–912, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0205255](https://arxiv.org/abs/astro-ph/0205255), [Bibcode](/source/Bibcode_(identifier)):[2002A&A...393..897R](https://ui.adsabs.harvard.edu/abs/2002A&A...393..897R), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20020943](https://doi.org/10.1051%2F0004-6361%3A20020943), [S2CID](/source/S2CID_(identifier)) [14070763](https://api.semanticscholar.org/CorpusID:14070763).

1. **[^](#cite_ref-SIMBAD_12-0)** ["pi Boo"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi+Boo), *[SIMBAD](/source/SIMBAD)*, [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg), retrieved 2017-10-18.

1. ^ [***a***](#cite_ref-Shoeller2010_13-0) [***b***](#cite_ref-Shoeller2010_13-1) [***c***](#cite_ref-Shoeller2010_13-2) Schöller, M.; et al. (November 2010), "Multiplicity of late-type B stars with HgMn peculiarity", *Astronomy and Astrophysics*, **522**: 12, [arXiv](/source/ArXiv_(identifier)):[1010.3643](https://arxiv.org/abs/1010.3643), [Bibcode](/source/Bibcode_(identifier)):[2010A&A...522A..85S](https://ui.adsabs.harvard.edu/abs/2010A&A...522A..85S), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201014246](https://doi.org/10.1051%2F0004-6361%2F201014246), [S2CID](/source/S2CID_(identifier)) [119273467](https://api.semanticscholar.org/CorpusID:119273467), A85

1. **[^](#cite_ref-vanLeeuwen2007_14-0)** van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600).

## External links

- Kaler, James B. (April 22, 2011), ["Pi Bootis"](http://stars.astro.illinois.edu/sow/piboo.html), *Stars*, University of Illinois, retrieved 2017-10-13.

- [HR 5475](http://webviz.u-strasbg.fr/viz-bin/VizieR-S?HR%205475)

- [CCDM J14407+1625](http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J14407%2b1625A)

- [Image Pi Boötis](http://aladin.u-strasbg.fr/AladinPreview?-c=14+40+43.5668%2B16+25+05.967&ident=HD+129174&submit=Aladin+previewer)

v t e Constellation of Boötes Boötes in Chinese astronomy Boötes Void List of stars in Boötes Stars Bayer α (Arcturus) β (Nekkar) γ (Seginus) δ (Qigong) ε (Izar, Pulcherrima) ζ η (Muphrid) θ ι κ λ (Xuange) μ1 (Alkalurops) μ2 ν1 ν2 ξ ο π ρ (Kalasungsang) σ (Genghe) τ (Tepiamenit) υ φ χ ψ ω Flamsteed 1 2 3 6 (e) 7 9 10 11 12 (d) 13 14 15 18 20 22 (f) 24 (g) 26 31 32 33 34 (Alrumh) 38 (Merga) 39 40 44 (Quadrans) 45 (c) 46 (b) 47 (k) 50 Variable R S T RX ZZ AB BL BP BX BY CE CH CI CN CP CR CX CY (101 Vir) DE EK HN HP HD 118508 118889 122563 125040 125351 (A) 125658 126128 126129 126141 126200 126271 127304 127334 127726 128093 128198 129132 129357 130084 130603 130917 131040 131473 131496 (Arcalís) 132029 132406 132563 134064 134335 135438 135530 135944 141399 Other 2MASS J15031961+2525196 CFBDSIR 1458+10 Gliese 526 HAT-P-4 LHS 2924 PSR J1544+4937 SDSS J1416+1348 SDSS J1433+1011 TVLM 513-46546 WASP-14 WD 1425+540 ZTF J153932.16+502738.8 Exoplanets HAT-P-4b HD 128311 b c HD 132406 b HD 136418 b (Awasis) τ Boötis b TOI-1853 b WASP-14b Star clusters NGC 5466 Galaxies NGC 5008 5248 5251 5416 5490 5500 5504 5508 5514 5523 5529 5532 5533 5535 5539 5541 5544 5545 5548 5557 5559 5562 5579 5582 5591 5601 5603 5609 5613 5614 5615 5624 5629 5630 5641 5642 5653 5665 5676 5681 5682 5683 5698 5714 5722 5752 5753 5754 5755 5772 5778 5784 5790 5820 5821 5829 5837 5857 5875 5876 5886 5888 5896 5929 5930 5966 Numbered I II III Other 3C 295 3C 299 3C 300 3C 303 3C 315 4C 19.44 4C +26.42 7C 1354+2552 Abell 2009 BCG Arp 302 B2 1420+32 B2 1441+26 CEERS-2112 CEERS-93316 CEERS2-588 CLASS B1359+154 Cloverleaf quasar DDO 190 EGS-zs8-1 EGS-z11-R0 EGSY8p7 H1426+428 IC 4397 IC 4461 IC 4462 IC 4481 IC 4516 IRAS 13349+2438 IRAS 14394+5332 IRAS 15206+3342 LEDA 2108986 MACS 1423-z7p64 MACS J1447.4+0827 BCG Maisie's Galaxy Markarian 463 Markarian 471 Markarian 478 MS 1455.0+2232 BCG MS 1512-cB58 NVSS J141343+433945 OQ 172 OQ 530 PG 1411+442 PG 1543+489 PGC 93125 PGC 1470080 PKS 1345+125 PKS 1413+135 QSO B1422+202 RBS 1467 RGZ J145001.5+144747 RGZ J145039.8+441829 SBS 1415+437 SDSS J135646.10+102609.0 SDSS J1430+2303 Teacup galaxy UGC 8669 UGC 9128 UGC 9425 UGC 9684 UGC 9796 ULAS J1342+0928 VV 191 Galaxy clusters Abell 1795 Abell 1991 BoRG-58 IDCS J1426.5+3508 Astronomical events GRB 990123 GRB 080319B SCP 06F6 SN 2003fg SN 2005bc SN 2020tlf Category

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Adapted from the Wikipedia article [Pi Boötis](https://en.wikipedia.org/wiki/Pi_Bo%C3%B6tis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Pi_Bo%C3%B6tis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.