Iota1 Librae

{{Short description|Multiple star system in the constellation Libra}}

{{Starbox begin

| name=Iota¹ Librae

}}

{{Starbox image

| image =

250px

| caption = Map of the constellation of Libra.

}}

{{Starbox observe

| epoch=J2000.0 (ICRS)

| constell=Libra

| ra= {{RA|15|12|13.29025}}

| dec= {{DEC|−19|47|30.1592}}

| appmag_v=+4.54

}}

{{Starbox character

| class=B9IVpSi + B9

| type= Blue subgiant

| b-v=−0.08

| u-b=−0.38

| variable = Alpha2 Canum Venaticorum

}}

{{Starbox astrometry

| radial_v=−11.6

| prop_mo_ra=−35.40

| prop_mo_dec=−32.79

| parallax=8.59

| parallax_footnote=

| p_error=0.25

| absmag_v=−0.79

}}

{{Starbox orbit

| reference =

| period_unitless = 8163.16 d

| eccentricity = 0.35

| periastron = 2433155 JD

| periarg = 7.6

| k1 = 3.4

}}

{{Starbox detail

| mass =

| radius =

| luminosity = 277

| temperature =

| gravity =

| metal_fe =

| rotational_velocity =

| age_myr =

}}

{{Starbox catalog

| names = {{odlist | B=ι¹ Lib | F=24 Librae | BD=−19°4047 | HD=134759 | HIP=74392 | HR=5652 | SAO=159090 | WDS=J15122-1948A }}{{cite simbad |title=iot01 Lib |accessdate=2017-12-16}}

}}

{{Starbox reference

|Simbad=iot+Lib

}}

Iota¹ Librae, Latinized from ι¹ Librae, is a quadruple star system in the constellation Libra. Its apparent magnitude is 4.54. It is located 379 light years from earth.[http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ50573aac4cd&-out.add=.&-source=V/137C/XHIP&recno=74147 Extended Hipparcos Compilation (XHIP) (+ Anderson, 2012)]

Visibility

Due to its southern location, although the star can be seen from most regions of the earth, observers in the southern hemisphere are more advantaged. Near Antarctica, it appears circumpolar, while it always remains invisible only in the vicinity of the Arctic Circle. Its magnitude of 4.5 means that naked-eye visibility is dependent on a sky sufficiently free from the effects of light pollution.

The best time for observation in the evening sky falls in the months between May and September; from both hemispheres of the period of visibility remains approximately the same, thanks to the position of the star not far from the celestial equator.

Physical

File:Iota1LibLightCurve.png for Iota¹ Librae plotted from STEREO data, adpated from Wraight et al. (2012)]]

Iota¹ Librae is a four star system. The inner pair, designated components Aa and Ab, form a spectroscopic binary with an orbital period of 22.35 years and an eccentricity of 0.35. The brighter member has a stellar classification of {{nowrap|B9 IVp Si}}, indicating it is a B-type subgiant star with an overabundance of silicon in the photosphere. It is a variable star of the Alpha2 Canum Venaticorum type with a magnitude that varies from 4.53 to 4.56, while its spectrum likewise shows variability.[http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ50573aac4cd&-out.add=.&-source=B/gcvs/nsv_cat&recno=6981 General Catalogue of Variable Stars (Samus + 2007-2012)] The secondary component is of class B9. The two stars are very close together (0.2 arcsec away), respectively of magnitude 5.1 and 5.5.[http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ50573aac4cd&-out.add=.&-source=B/wds/wds&recno=6981 The Washington Visual Double Star Catalog (Mason + 2001-2012)].[http://www.alcyone.de/SIT/bsc/HR5652.html Alcyone]

A third component is located 57 arcsec distant; it is a star of the tenth magnitude, Iota¹ Librae B. The third component is also a double star, of equal magnitudes, 1.9 arcseconds apart.Burnam's Celestial Handbook, pp. 1107-1108.

Due to its position on the ecliptic, it is sometimes obscured by the Moon or planets. A lunar occultation took place April 4, 2012.{{Cite web | url = http://www.oato.inaf.it/index.php?option=com_events&task=view_detail&agid=2141&year=2012&month=04&day=09&Itemid=340&catids=87 | title = Moon occults ι Librae (2012-04-09 02:03 CEST) | publisher = Turin Astronomical Observatory | accessdate = March 23, 2012 | url-status = dead | archiveurl = https://archive.today/20130413060144/http://www.oato.inaf.it/index.php?option=com_events&task=view_detail&agid=2141&year=2012&month=04&day=09&Itemid=340&catids=87 | archivedate = April 13, 2013 }}

References

{{reflist|refs=

{{cite journal

| last1=Wraight |first1=K. T. |last2=Fossati |first2=L.

| last3=Netopil |first3=M. |last4=Paunzen |first4=E.

| last5=Rode-Paunzen |first5=M. |last6=Bewsher |first6=D.

| last7=Norton |first7=A. J. |last8=White |first8=Glenn J.

| title=A photometric study of chemically peculiar stars with the STEREO satellites – I. Magnetic chemically peculiar stars

| journal=Monthly Notices of the Royal Astronomical Society |date=February 2012

| volume=420 |issue=1 |pages=757–772 |doi=10.1111/j.1365-2966.2011.20090.x |bibcode=2012MNRAS.420..757W |doi-access=free |arxiv=1110.6283 }}

{{citation

| first=F. | last=van Leeuwen | date=November 2007

| title=Validation of the new Hipparcos reduction

| journal=Astronomy and Astrophysics

| volume=474 | issue=2 | pages=653–664

| bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357

| postscript=. | arxiv=0708.1752 | s2cid=18759600 }}

{{citation

| 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 | postscript=. }}

{{citation

| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.

| title=A catalogue of multiplicity among bright stellar systems

| journal=Monthly Notices of the Royal Astronomical Society

| volume=389 | issue=2 | pages=869–879 | date=September 2008

| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E

| postscript=. | arxiv=0806.2878 | s2cid=14878976 }}

{{citation

| display-authors=1 | last1=Pourbaix | first1=D.

| last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H.

| last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I.

| last6=Levato | first6=H. | last7=Morrell | first7=N. I.

| last8=Torres | first8=G. | last9=Udry | first9=S.

| year=2004 | pages=727–732 | volume=424

| title=SB9: The Ninth Catalogue of Spectroscopic Binary Orbits

| journal=Astronomy & Astrophysics | bibcode=2004A&A...424..727P

| doi=10.1051/0004-6361:20041213 | postscript=. | arxiv=astro-ph/0406573| s2cid=119387088 }}

}}

External links

[http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Iota+Librae&submit=display+all+measurements Simbad archive]

Category:Libra (constellation)

Category:B-type subgiants

Librae, Iota1

Category:Alpha2 Canum Venaticorum variables

Librae, 24

Category:Durchmusterung objects

074392

134759

5652