iota Carinae

{{Starbox begin

| name = ι Carinae

}}

{{Starbox image

| image=

{{Location mark

|image=Carina constellation map.svg|alt=|float=center|width=280

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=ι Car

|x=366|y=298

}}

|caption=Location of ι Carinae (circled in red)

}}

{{Starbox observe

| epoch = J2000

| ra = {{RA|09|17|05.40686}}

| dec = {{DEC|-59|16|30.8353}}

| appmag_v = 2.21

| constell = Carina

}}

{{Starbox character

| class = A7 Ib

| b-v = +0.18

| u-b = +0.16

| variable = Suspected

}}

{{Starbox astrometry

| radial_v = 13.3

| prop_mo_ra = −19.03

| prop_mo_dec = +13.11

| parallax = 4.26

| p_error = 0.1

| parallax_footnote =

| absmag_v = −5.1

}}

{{Starbox detail

| mass = 6.9

| radius = 46.4–50.1

| luminosity = 4,900

| temperature = 7,500–7,700

| metal_fe = −0.14

| rotation =

| rotational_velocity = 10.0

| gravity = {{val|1.85|0.1}}

| age_myr = 56

}}

{{Starbox catalog

| names = iota Car, HR 3699, HD 80404, SAO 236808, FK5 351, CD−58°2529, CPD−58°1465, NSV 04444, HIP 45556.

}}

{{Starbox reference

|Simbad=iota+Car

}}

Iota Carinae (ι Carinae, abbreviated Iota Car, ι Car), officially named Aspidiske {{IPAc-en|,|æ|s|p|ɪ|'|d|I|s|k|iː}},{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |access-date=28 July 2016}} is a star in the southern constellation of Carina. With an apparent visual magnitude of 2.2, it is one of the brighter stars in the night sky.

Appearance and location

The star and rest of southern Carina never sets on places from about 34° S southwards including Cape Town; its northernmost viewpoints are unobstructed southern horizons near to the 30th parallel north, once a day.

The False Cross is an asterism formed from Iota Carinae, Delta Velorum, Kappa Velorum and Epsilon Carinae. It is so called because it is sometimes mistaken for the Southern Cross, causing errors in astronavigation.{{cite book|last=Moore|first=Patrick|title=Patrick Moore's Astronomy: Teach Yourself|publisher=Hachette |year=2010|isbn=978-1444129779|url=https://books.google.com/books?id=D7M0Rgc1ONAC&pg=PT127}}

The star appears 46.0' (0.7668°) WSW of V357 Carinae, a mid-third-magnitude star, also forming part of the asterism and leading to its long, narrow projection which culminates in Canopus.[http://in-the-sky.org/skymap2.php?year=2019&month=1&day=1&town=3369157 In the Sky Map], Dominic Ford, 2011–2019.

Nomenclature

ι Carinae (Latinised to Iota Carinae) is the star's Bayer designation.

It has the traditional cognate names Aspidiske (not be confused with Asmidiske, the proper name of Xi Puppis), Scutulum and Turais (or Tureis, a name shared with Rho Puppis). Turais is the Arabic تُرَيْس turais "small shield" (diminutive), while Aspidiske and Scutulum are Greek and Latin translations from ασπίδα and scūtum. In 2016, the International Astronomical Union formed its Working Group on Star Names (WGSN){{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|access-date=22 May 2016}} to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}} included a table of the first two batches of names it approved which included Aspidiske for this star.

In Chinese, {{lang|zh|海石}} ({{lang|zh-Latn|Hǎi Shí}}), meaning Sea Rock, refers to an asterism consisting of Iota Carinae, Epsilon Carinae, HD 83183, HD 84810 and Upsilon Carinae.{{in lang|zh}} 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}. Consequently, Iota Carinae itself is known as {{lang|zh|海石二}} ({{lang|zh-Latn|Hǎi Shí èr}}, {{langx|en|the Second Star of Sea Rock}}).{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm 香港太空館 – 研究資源 – 亮星中英對照表] {{webarchive|url=https://web.archive.org/web/20100811014924/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_ama_b.htm |date=2010-08-11 }}, Hong Kong Space Museum. Accessed on line November 23, 2010.

Properties

Based on parallax measurements this star is about {{Convert|770|ly|pc|abbr=off|lk=on}} from the Earth. It has a stellar classification of A7 Ib, with the luminosity class of 'Ib' indicating it has reached the stage of its evolution where it has expanded to become a lower-luminosity supergiant. It is just entering the Hertzsprung gap of the Hertzsprung–Russell diagram, and is evolving towards a red supergiant phase.{{Cite journal |last1=Neuhäuser |first1=R |last2=Torres |first2=G |last3=Mugrauer |first3=M |last4=Neuhäuser |first4=D L |last5=Chapman |first5=J |last6=Luge |first6=D |last7=Cosci |first7=M |date=2022-07-29 |title=Colour evolution of Betelgeuse and Antares over two millennia, derived from historical records, as a new constraint on mass and age |journal=Monthly Notices of the Royal Astronomical Society |volume=516 |issue=1 |pages=693–719 |doi=10.1093/mnras/stac1969 |doi-access=free |issn=0035-8711|arxiv=2207.04702 |bibcode=2022MNRAS.516..693N }}

Iota Carinae has around seven times the Sun's mass and has expanded to roughly 50 times the Sun's radius. It is radiating about 4,900 times the luminosity of the Sun. However, this luminosity appears to vary, causing the star's apparent magnitude to range between 2.23–2.28. This energy is being radiated into space from the star's outer envelope at an effective temperature of 7,500 K, giving Iota Carinae the white hue typical of an A-type star. Being short of the rough initial mass limit above which stars collapse and explode as supernovae, Iota Carinae will likely end its life as a white dwarf with roughly the current mass of the Sun, similar to Sirius B today (which was also estimated to have an initial mass of up to 7 solar masses).{{Cite journal |last=Whittet |first=D. C. B. |date=1999-12-01 |title=A physical interpretation of the 'red Sirius' anomaly |journal=Monthly Notices of the Royal Astronomical Society |volume=310 |issue=2 |pages=355–359 |doi=10.1046/j.1365-8711.1999.02975.x |doi-access=free |bibcode=1999MNRAS.310..355W |issn=0035-8711}}

Due to precession of the Earth's axis of rotation, in the next 7,500 years the south celestial pole will pass close to this star and Upsilon Carinae and it will become the South Star around 8100 CE.{{Cite web|url=http://moonkmft.co.uk/Precession.html|title = Precession}}

References

{{Reflist|refs=

{{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 |arxiv = 0708.1752 | s2cid=18759600 }}

{{Cite journal |last1=Gray |first1=R. O. |last2=Garrison |first2=R. F. |date=1989-07-01 |title=The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation |bibcode=1989ApJS...70..623G |journal=The Astrophysical Journal Supplement Series |volume=70 |pages=623 |doi=10.1086/191349 |issn=0067-0049}}

{{citation | display-authors=1 | title=Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions | journal=Veröff. Astron. Rechen-Inst. Heidelb | volume=35 | last1=Wielen | first1=R. | last2=Schwan | first2=H. | last3=Dettbarn | first3=C. | last4=Lenhardt | first4=H. | last5=Jahreiß | first5=H. | last6=Jährling | first6=R. | publisher=Astronomisches Rechen-Institut Heidelberg | issue=35 | date=1999 | page=1 | bibcode=1999VeARI..35....1W }}

{{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 | date=1966 | bibcode=1966CoLPL...4...99J }}

{{citation | display-authors=1 | last1=Ruban | first1=E. V. | last2=Alekseeva | first2=G. A. | last3=Arkharov | first3=A. A. | last4=Hagen-Thorn | first4=E. I. | last5=Galkin | first5=V. D. | last6=Nikanorova | first6=I. N. | last7=Novikov | first7=V. V. | last8=Pakhomov | first8=V. P. | last9=Puzakova | first9=T. Yu. | title=Spectrophotometric observations of variable stars | journal=Astronomy Letters | volume=32 | issue=9 | pages=604–607 |date=September 2006 | doi=10.1134/S1063773706090052 | bibcode=2006AstL...32..604R | s2cid=121747360 }}

{{citation | display-authors=1 | last1=Smiljanic | first1=R. | last2=Barbuy | first2=B. | last3=de Medeiros | first3=J. R. | last4=Maeder | first4=A. | title=CNO in evolved intermediate mass stars | journal=Astronomy and Astrophysics | volume=449 | issue=2 | pages=655–671 |date=April 2006 | doi=10.1051/0004-6361:20054377 | bibcode=2006A&A...449..655S |arxiv = astro-ph/0511329 | s2cid=3711409 }}

{{citation | title=iot Car -- Variable Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Iota+Carinae | access-date=2012-01-14 }}

{{citation | first1=James B. | last1=Kaler | title=ASPIDISKE (Iota Carinae) | work=Stars | publisher=University of Illinois | url=http://stars.astro.illinois.edu/sow/aspidiske.html | access-date=2012-01-14 }}

{{citation | first1=Richard Hinckley | last1=Allen | title=Star-names and their meanings | journal=New York | publisher=G. E. Stechert | date=1899 | page=74 | url=https://books.google.com/books?id=5xQuAAAAIAAJ&pg=PA74 | bibcode=1899sntm.book.....A }}

{{Cite journal |last=Ayres |first=Thomas R. |date=2018-02-20 |title=Cracking the Conundrum of F-Supergiant Coronae |journal=The Astrophysical Journal |volume=854 |issue=2 |pages=95 |arxiv=1802.02552 |bibcode=2018ApJ...854...95A |doi=10.3847/1538-4357/aaa6d7 |issn=0004-637X |doi-access=free}}

{{Cite journal |last1=Neiner |first1=Coralie |last2=Oksala |first2=Mary E. |last3=Georgy |first3=Cyril |last4=Przybilla |first4=Norbert |last5=Mathis |first5=Stéphane |last6=Wade |first6=Gregg |last7=Kondrak |first7=Matthias |last8=Fossati |first8=Luca |last9=Blazère |first9=Aurore |last10=Buysschaert |first10=Bram |last11=Grunhut |first11=Jason |date=2017-10-01 |title=Discovery of magnetic A supergiants: the descendants of magnetic main-sequence B stars |bibcode=2017MNRAS.471.1926N |arxiv=1707.00560|journal=Monthly Notices of the Royal Astronomical Society |volume=471 |issue=2 |pages=1926–1935 |doi=10.1093/mnras/stx1549 |doi-access=free |issn=0035-8711}}

{{citation |title=The Colour of Stars |date=December 21, 2004 |work=Australia Telescope, Outreach and Education |publisher=Commonwealth Scientific and Industrial Research Organisation |url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |access-date=2012-01-16 |url-status=dead |archive-url=https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archive-date=March 18, 2012 }}

{{cite journal|bibcode=2016NewA...47...46T|arxiv=1512.03762|title=Abundance analysis of the supergiant stars HD 80057 and HD 80404 based on their UVES Spectra|journal=New Astronomy|volume=47|pages=46–56|last1=Tanrıverdi|first1=T.|last2=Baştürk|first2=Ö.|year=2016|doi=10.1016/j.newast.2016.02.006|s2cid=119220398}}

}}

Category:A-type supergiants

Category:Carina (constellation)

Carinae, Iota

Category:Durchmusterung objects

Category:Suspected variables