Lambda Boötis

{{Starbox begin

| name = λ Boötis

}}

{{Starbox image

| image =

{{Location mark

|image=Boötes constellation map.svg|alt=|float=center|width=220

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=λ Boötis

|x=656|y=207

}}

| caption = Location of λ Boötis (circled)

}}

{{Starbox observe

| epoch = J2000.0

| constell = Boötes

| ra = {{RA|14|16|23.018}}

| dec = {{DEC|+46|05|17.90}}

| appmag_v = +4.18

}}

{{Starbox character

| class = A0p λB

| b-v = +0.08

| u-b = +0.05

| variable = δ Sct

}}

{{Starbox astrometry

| radial_v = {{Val|−7.9|1.6}}

| prop_mo_ra = −187.698

| prop_mo_dec = 159.309

| pm_footnote =

| parallax = 32.5885

| p_error = 0.1410

| parallax_footnote =

| absmag_v = {{Val|+1.71|0.23}}

}}

{{Starbox detail

| mass = {{val|1.66|0.19|0.16}}

| radius = {{val|1.70|0.10}}

| gravity = 4.188

| luminosity = {{val|16.3|0.6}}

| temperature = {{val|8887|242|fmt=commas}}

| metal_fe =

| rotational_velocity = 100

| age_gyr = {{val|2.8|1.1|0.8}}

}}

{{Starbox catalog

| names = {{odlist | name=Xuange | B=λ Boo | F=19 Boötis | BD=+46°1949 | FK5=527 | GJ=3837 | HD=125162 | HIP=69732 | HR=5351 | SAO=44965 | GC=19273 }}

}}

{{Starbox reference

| Simbad = lam+Boo

}}

Lambda Boötis is a star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from λ Boötis, and abbreviated Lam Boo or λ Boo. It has the official name Xuange, pronounced {{IPAc-en|ˈ|ʃ|w|ɛ|n|g|ə}}.{{cn|date=June 2019}}

With an apparent visual magnitude of +4.18, it is faintly visible to the naked eye. Based on parallax measurements, it is {{convert|100.1|ly|pc|abbr=out|lk=on}} distant from Earth. This star is drifting closer to the Sun with a radial velocity of −8 km/s.

File:LamBooLightCurve.png for Lambda Boötis, plotted from TESS data]]

This is a white hued A-type main-sequence star with a stellar classification of A0p λB. It is the prototype of a group of rare stars known as Lambda Boötis stars, all of which are dwarf stars with unusually low abundances of metals in their spectra. Its diameter has been directly measured to be 1.7 times that of the Sun. This is a Delta Scuti variable star with a period of {{convert|0.0230|days|minutes|disp=out|abbr=off}} and an amplitude of 0.0020 in visual magnitude.

This star displays an infrared excess that may be the result of a circumstellar disk of orbiting debris, or else a bow wave from its motion through the interstellar medium.

Nomenclature

λ Boötis (Latinised to Lambda Boötis) is the star's Bayer designation.

In Chinese astronomy, Lambda Boötis is called 玄戈, Pinyin: Xuángē, meaning 'sombre lance', because this star is marking itself and standing alone in the Sombre Lance asterism, Purple Forbidden enclosure (see : Chinese constellations). 玄戈 (Xuángē) westernized into Heuen Ko, but that name was assigned to Gamma Boötis by R. H. Allen, with the meaning of 'the heavenly spear'. In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name Xuange for Lambda Boötis on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.

This star, along with the Aselli (Theta Boötis, Iota Boötis and Kappa Boötis), were Al Aulād al Dhiʼbah (ألعولد ألذعب - al aulād al dhiʼb), "the Whelps of the Hyenas". Al Aulād al Dhiʼbah or Aulad al Thiba was the title of this star in a 1971 NASA memorandum.

References

{{reflist|refs=

{{cite simbad

| title=lam boo | access-date=2025-05-29 }}

{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=2 June 2025}}

{{Cite journal | display-authors=1 | last1=Montesinos | first1=B. | last2=Eiroa | first2=C. | last3=Mora | first3=A. | last4=Merín | first4=B. | title=Parameters of Herbig Ae/Be and Vega-type stars | journal=Astronomy and Astrophysics | volume=495 | issue=3 | pages=901–917 |date=March 2009 | doi=10.1051/0004-6361:200810623 | bibcode=2009A&A...495..901M |arxiv = 0811.3557 | s2cid=14972955 }}

{{Cite journal | last1=Song | first1=Inseok | last2=Caillault | first2=J.-P. | last3=Barrado y Navascués | first3=David | last4=Stauffer | first4=John R. | title=Ages of A-Type Vega-like Stars from uvbyβ Photometry | journal=The Astrophysical Journal | volume=546 | issue=1 | pages=352–357 |date=February 2001 | doi=10.1086/318269 | bibcode=2001ApJ...546..352S |arxiv = astro-ph/0010102 | s2cid=18154947 }}

{{cite journal | bibcode=1995ApJS...99..135A | title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars | journal=Astrophysical Journal Supplement | volume=99 | pages=135 | last1=Abt | first1=Helmut A. | last2=Morrell | first2=Nidia I. | year=1995 | doi=10.1086/192182 | doi-access=free }}

{{Cite journal | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J }}

{{Cite journal | last=Gontcharov | first=G. A. | title=Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system | journal=Astronomy Letters | volume=32| issue=11| pages=759–771| date=November 2006 | doi=10.1134/S1063773706110065 | bibcode=2006AstL...32..759G | arxiv=1606.08053 | s2cid=119231169 }}

{{Cite journal | display-authors=1 | title=The status of Galactic field λ Bootis stars in the post-Hipparcos era | last1=Paunzen | first1=E. | last2=Iliev | first2=I. Kh. | last3=Kamp | first3=I. | last4=Barzova | first4=I. S. | journal=Monthly Notices of the Royal Astronomical Society | volume=336 | issue=3 | pages=1030–1042 | date=November 2002 | doi=10.1046/j.1365-8711.2002.05865.x | doi-access=free | bibcode=2002MNRAS.336.1030P | arxiv=astro-ph/0207488 | s2cid=2389489 }}

{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |access-date=16 December 2017}}

{{cite book

| title=Star Names: Their Lore and Meaning

| last=Allen | first=R. H. | author-link=Richard Hinckley Allen

| page=105 | year=1963 | isbn=((978-0-486-21079-7))

| edition=Reprint | publisher=Dover Publications Inc

| location=New York, NY

| url=https://archive.org/details/starnamestheirlo00alle/page/105

| access-date=2010-12-12 | url-access=registration }}

{{cite web

| title=Star Names — Their Lore and Meaning: Boötes

| first=Richard Hinckley | last=Allen

| url=http://www.constellationsofwords.com/stars/Seginus.html

| access-date=2025-05-29 }}

{{cite book

| title=Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars

| first=Jack W. | last=Rhoads | date=November 15, 1971

| publisher=Jet Propulsion Laboratory, California Institute of Technology

| url=https://ntrs.nasa.gov/citations/19720005197

| access-date=2025-05-29 }}

{{cite journal

| title=The Angular Diameter of λ Boötis

| author=Ciardi | last2=Van Belle | first2=Gerard T.

| last3=Boden | first3=Andrew F. | last4=Ten Brummelaar | first4=T.

| last5=McAlister | first5=H. A. | last6=Bagnuolo, Jr. | first6=W. G.

| last7=Goldfinger | first7=P. J. | last8=Sturmann | first8=J.

| last9=Sturmann | first9=L. | last10=Turner | first10=N.

| last11=Berger | first11=D. H. | last12=Thompson | first12=R. R.

| last13=Ridgway | first13=S. T.

| bibcode=2007ApJ...659.1623C|arxiv = astro-ph/0612723

| display-authors=1 | journal=The Astrophysical Journal

| volume=659 | issue=2 | pages=1623–1628 | year=2007

| doi=10.1086/512077 | s2cid=17861605 }}

{{cite web

| title=IAU Working Group on Star Names (WGSN)

| publisher=International Astronomical Union

| url=https://www.iau.org/science/scientific_bodies/working_groups/280/

| access-date=2016-05-22 }}

{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060614.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 14 日] {{Webarchive|url=https://web.archive.org/web/20110716122337/http://aeea.nmns.edu.tw/2006/0606/ap060614.html |date=2011-07-16 }}

{{cite journal

| title=IR excesses around nearby Lambda Boo stars are caused by debris discs rather than ISM bow waves

| last1=Draper | first1=Z. H. | last2=Matthews | first2=B. C.

| last3=Kennedy | first3=G. M. | last4=Wyatt | first4=M. C.

| last5=Venn | first5=K. A. | last6=Sibthorpe | first6=B.

| journal=Monthly Notices of the Royal Astronomical Society

| volume=456 | issue=1 | pages=459 | year=2016

| display-authors=1 | bibcode=2016MNRAS.456..459D

| doi=10.1093/mnras/stv2696 | doi-access=free

| arxiv=1511.05919 | s2cid=118343020 }}

{{cite journal | display-authors=1

| title=Statistical Properties of Galactic δ Scuti Stars: Revisited