lambda Ursae Minoris

{{Starbox begin

| name=λ Ursae Minoris

}}

{{Starbox image

| image = 250px

| caption = A light curve for Lambda Ursae Minoris, plotted from Hipparcos data

}}

{{Starbox observe

| epoch=J2000.0

| constell=Ursa Minor

| ra={{RA|17|16|56.4107}}

| dec={{DEC|+89|02|15.734}}

| appmag_v=+6.38

}}

{{Starbox character

| class=M3+ IIIa

| b-v = +1.57

| u-b = +1.79

| variable = SRb

}}

{{Starbox astrometry

| radial_v = +0.19

| prop_mo_ra = {{val|-23.989}}

| prop_mo_dec = {{val|3.463}}

| parallax = 3.7084

| p_error = 0.1329

| parallax_footnote =

| dist_ly=

| dist_pc=

| absmag_v=−0.85

}}

{{Starbox detail

| mass =

| temperature = 3,772

| radius = 64

| luminosity = 741

}}

{{Starbox catalog

| names=HR 7394, HD 183030, BD+88°112, FK5 914, HIP 84535, SAO 3020

}}

{{Starbox reference

| Simbad = lambda+UMi

}}

Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38, making it very faintly visible to the naked eye under the best observing conditions. It is approximately 880 light years from Earth.

Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core. AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes. Its variability was discovered by the Hipparcos satellite and it was entered into the General Catalogue of Variable Stars in 1999.

This star was used from 1882 as a reference to measure the magnitudes of stars in the northern hemisphere for the 1908 Revised Harvard Photometry catalogue. Sigma Octantis was used for the southern hemisphere. It was then noted that "Neither of these stars appears to vary perceptibly" but that, due to the procedures used "if they did, the variation would have no effect on the final measures."

References

{{reflist | refs =

{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=VizieR On-line Data Catalog|last1=Ducati|first1=J. R.|year=2002|volume=2237 }}

{{cite web

| url=https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats

| website=Centre de Données astronomiques de Strasbourg | title=/ftp/cats/more/HIP/cdroms/cats

| publisher=Strasbourg astronomical Data Center |access-date=15 October 2022}}

{{cite journal

| title=XHIP: An extended hipparcos compilation

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015

| arxiv=1108.4971 | s2cid=119257644 }}

{{cite journal|bibcode=1992AJ....104..275E |title=Asymptotic Giant Branch Stars Near the Sun |journal=The Astronomical Journal |volume=104 |pages=275 |last1=Eggen |first1=Olin J. |year=1992 |doi=10.1086/116239 }}

{{cite journal|bibcode=1967PDAO...13...47Y|title=MK Spectral Types of Bright M-Type Stars|journal=Publications of the Dominion Astrophysical Observatory Victoria|volume=13|pages=47|last1=Yamashita|first1=Y.|year=1967}}

{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|pages=B/GCVS|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode=1999IBVS.4659....1K|title=The 74th Special Name-list of Variable Stars|journal=Information Bulletin on Variable Stars|volume=4659|pages=1|last1=Kazarovets|first1=E. V.|last2=Samus|first2=N. N.|last3=Durlevich|first3=O. V.|last4=Frolov|first4=M. S.|last5=Antipin|first5=S. V.|last6=Kireeva|first6=N. N.|last7=Pastukhova|first7=E. N.|year=1999}}

{{cite book|bibcode=1991bsc..book.....H|year=1991|title=The Bright star catalogue|last1=Hoffleit|first1=Dorrit|last2=Jaschek|first2=Carlos}}

{{cite journal

| title=Revised Harvard Photometry

| last1=Pickering | first1=Edward Charles

| journal=Annals of the Astronomical Observatory of Harvard College

| volume=50 | pages=2 | year=1908

| bibcode=1908AnHar..50....1P }}

}}

External links

{{WikiSky}}
[http://stars.astro.illinois.edu/sow/lambdaumi.html LAMBDA UMI (Lambda Ursae Minoris)] – Jim Kaler

Ursae Minoris, Lambda

Category:Ursa Minor

Category:M-type giants

Category:Semiregular variable stars