BP Boötis

{{Starbox image

| image=

{{Location mark

|image=Boötes constellation map.svg|alt=|float=center|width=240

|label=|position=right

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

|x=174|y=32

}}

|caption=Location of BP Boötis (circled)

}}

{{Starbox observe

| epoch = J2000

| constell = Boötes

| ra = {{RA|15|42|50.760818}}

| dec = {{DEC|+52|21|39.24441}}

| appmag_v = 5.48

}}

{{Starbox character

| type =

| class = {{nowrap|A0 Vp Si Cr}}

| b-v = {{Val|−0.042|0.004}}

| u-b =

| variable = α² CVn

}}

{{Starbox astrometry

| radial_v = {{Val|−16.1|2.8}}

| prop_mo_ra = −66.214

| prop_mo_dec = +29.308

| parallax = 10.92

| p_error = 0.18

| parallax_footnote =

| absmag_v = +0.48

}}

{{Starbox detail

| source =

| mass = {{Val|2.58|0.07}}

| radius = {{Val|2.7|0.2}}

| luminosity = 65

| temperature = 9,954

| metal_fe =

| gravity = {{Val|3.99|0.07}}

| rotation = 1.29557 days

| rotational_velocity = 69

| age_myr = 170

}}

{{Starbox catalog

| names={{odlist | V=BP Boo | BD=+52°1898 | FK5=3247 | HD=140728 | HIP=76957 | HR=5857 | SAO=29628 | GC=21154 }}

}}

{{Starbox reference

| Simbad=BP+Boo

}}

Image:BPBooLightCurve.png for BP Boötis, plotted from TESSdata]]

BP Boötis is a solitary variable star in the northern constellation of Boötes, near the northern constellation border with Draco. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude that fluctuates around 5.48. The star is located 299 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −16 km/s.

The star, often called HD 140728 before it was known to be variable, was transferred from Boötes to Quadrans Muralis. Later, when the International Astronomical Union officially recognised constellations, Quadrans Muralis became obsolete, so this star was moved back to Boötes.{{Cite book |last=Barentine |first=John C. |url=https://books.google.com/books?id=u_7NCgAAQBAJ&dq=BP+Bo%C3%B6tis&pg=PA487 |title=The Lost Constellations: A History of Obsolete, Extinct, or Forgotten Star Lore |publisher=Springer |year=2016 |isbn=978-3-319-22794-8 |pages=304}} In 1962, William Wehlau announced that the star's brightness varied, based on observations made from 1958 through 1960.

This is an Ap star with a stellar classification of {{nowrap|A0 Vp Si Cr}}, showing abundance anomalies of silicon and chromium. It is an Alpha² Canum Venaticorum variable that varies in brightness by 0.02 magnitude over a period of 1.3 days. The distribution of silicon across the surface appears to be associated with the magnetic field of the star, with depleted regions appearing around the magnetic poles.

BP Boötis is 170 million years old with a projected rotational velocity of 69 km/s, having a rotation period of 1.29557 days. It has 2.6 times the mass of the Sun and 2.7 times the Sun's radius. The star is radiating 65 times the luminosity of the Sun from its photosphere at an effective temperature of 9,954 K.

References

{{reflist|refs=

{{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=8 December 2021}}

{{citation

| title=The distribution of silicon on BP Boo

| last=Hatzes | first=Artie P. | postscript=.

| journal=Monthly Notices of the Royal Astronomical Society

| volume=245 | page=56 | date=July 1990

| doi=10.1093/mnras/245.1.56 | bibcode=1990MNRAS.245...56H | doi-access=free }}

{{cite journal

| last1=Wehlau | first1=William | title=Photometry of γ Equulei and HD 140728

| journal=Publications of the Astronomical Society of the Pacific | date=August 1962 | volume=74 | issue=439

| pages=286–290 | doi=10.1086/127810 | bibcode=1962PASP...74..286W

| url=https://articles.adsabs.harvard.edu/pdf/1962PASP...74..286W | access-date=2 December 2024}}

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| bibcode=2008MNRAS.389..869E | arxiv=0806.2878

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| arxiv=1501.03154 | s2cid=33401607 | postscript=. }}

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{{citation

| last1=North | first1=P. | postscript=.