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This is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of B2&nbsp;IIIne.<ref name=apj157_313/> The 'e' notation indicates the [[stellar spectrum|spectrum]] displays [[emission line]]s, which means this is a [[Be star]] that is surrounded by hot, circumstellar gas. It is spinning rapidly with a [[projected rotational velocity]] of 375&nbsp;km/s.<ref name=coapa239_1/> The [[Doppler effect]] from this rotation is causing the [[absorption line]]s to widen and become nebulous, as indicated by the 'n' notation in the stellar class.
This is an [[stellar evolution|evolved]] [[giant star]] with a [[stellar classification]] of B2&nbsp;IIIne.<ref name=apj157_313/> The 'e' notation indicates the [[stellar spectrum|spectrum]] displays [[emission line]]s, which means this is a [[Be star]] that is surrounded by hot, circumstellar gas. It is spinning rapidly with a [[projected rotational velocity]] of 375&nbsp;km/s.<ref name=coapa239_1/> The [[Doppler effect]] from this rotation is causing the [[absorption line]]s to widen and become nebulous, as indicated by the 'n' notation in the stellar class.


[[File:IotaAraLightCurve.png|thumb|left|A [[light curve]] for Iota Arae, plotted from ''[[Transiting Exoplanet Survey Satellite|TESS]]'' data<ref name=MAST/>]]
Iota Arae has around 8.3<ref name=mnras410_1_190/> times the mass of the Sun and is shining brightly with 5,740<ref name=an331_4_349/> times the Sun's luminosity. This energy is being radiated into space from the [[stellar atmosphere|outer atmosphere]] at an [[effective temperature]] of 21,380&nbsp;K,<ref name=aaa515_A11/> giving it the characteristic blue-white hue of a [[B-type star]].<ref name=csiro/>
Iota Arae has around 8.3<ref name=mnras410_1_190/> times the mass of the Sun and is shining brightly with 5,740<ref name=an331_4_349/> times the Sun's luminosity. This energy is being radiated into space from the [[stellar atmosphere|outer atmosphere]] at an [[effective temperature]] of 21,380&nbsp;K,<ref name=aaa515_A11/> giving it the characteristic blue-white hue of a [[B-type star]].<ref name=csiro/>
The [[General Catalog of Variable Stars]] classifies it as a BE variable star, ranging from [[Photometric_system#Photometric_letters|visual]] magnitude 5.18 to 5.26 with a period of 13.36 hours.<ref name=gcvs/> In a study of the ''[[Hipparcos]]'' data, it was found to vary in brightness by 0.054 in magnitude with no clear period.<ref name=aaa507_2_11411201/>
The [[General Catalog of Variable Stars]] classifies it as a BE variable star, ranging from [[Photometric_system#Photometric_letters|visual]] magnitude 5.18 to 5.26 with a period of 13.36 hours.<ref name=gcvs/> In a study of the ''[[Hipparcos]]'' data, it was found to vary in brightness by 0.054 in magnitude with no clear period.<ref name=aaa507_2_11411201/>
{{clear left}}


==References==
==References==
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<ref name=gcvs>{{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|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}</ref>
<ref name=gcvs>{{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|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}</ref>

<ref name=MAST>{{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}}</ref>


<ref name=Anderson2012>{{citation
<ref name=Anderson2012>{{citation

Revision as of 03:00, 4 January 2023

Iota Arae
Diagram showing star positions and boundaries of the Ara constellation and its surroundings
The location of ι Arae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ara
Right ascension 17h 23m 16.07715s[1]
Declination –47° 28′ 05.5073″[1]
Apparent magnitude (V) 5.245[2]
Characteristics
Spectral type B2 IIIne[3]
U−B color index –0.82[4]
B−V color index –0.11[4]
R−I color index –0.08
Variable type BE[5]
Astrometry
Radial velocity (Rv)–19[6] km/s
Proper motion (μ) RA: –4.35[1] mas/yr
Dec.: –17.59[1] mas/yr
Parallax (π)3.49 ± 0.26 mas[1]
Distance930 ± 70 ly
(290 ± 20 pc)
Absolute magnitude (MV)−2.06[7]
Details
Mass8.3 ± 0.4[8] M☉
Luminosity (bolometric)5,740[9] L☉
Surface gravity (log g)4.10[2] cgs
Temperature21,380[2] K
Rotational velocity (v sin i)375[10] km/s
Age30.0 ± 7.4[8] Myr
Other designations
ι Ara, CD –47° 11484, FK5 3379, HD 157042, HIP 85079, HR 6451, NSV 8566, SAO 227886.[11]
Database references
SIMBADdata

Iota Arae, Latinized from ι Arae, is the Bayer designation for a star in the southern constellation of Ara. It is approximately 930 light-years (290 parsecs)[1] from Earth, give or take a 70 light-year margin of error, and has an apparent visual magnitude of 5.25.[4] Based upon the Bortle Dark-Sky Scale, this means the star is visible to the naked eye from suburban skies.

This is an evolved giant star with a stellar classification of B2 IIIne.[3] The 'e' notation indicates the spectrum displays emission lines, which means this is a Be star that is surrounded by hot, circumstellar gas. It is spinning rapidly with a projected rotational velocity of 375 km/s.[10] The Doppler effect from this rotation is causing the absorption lines to widen and become nebulous, as indicated by the 'n' notation in the stellar class.

A light curve for Iota Arae, plotted from TESS data[12]

Iota Arae has around 8.3[8] times the mass of the Sun and is shining brightly with 5,740[9] times the Sun's luminosity. This energy is being radiated into space from the outer atmosphere at an effective temperature of 21,380 K,[2] giving it the characteristic blue-white hue of a B-type star.[13] The General Catalog of Variable Stars classifies it as a BE variable star, ranging from visual magnitude 5.18 to 5.26 with a period of 13.36 hours.[5] In a study of the Hipparcos data, it was found to vary in brightness by 0.054 in magnitude with no clear period.[14]

References

  1. ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. ^ a b c d Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID 118362423.
  3. ^ a b Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313, Bibcode:1969ApJ...157..313H, doi:10.1086/150069.
  4. ^ a b c Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series, 61: 387–405, Bibcode:1985A&AS...61..387K.
  5. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Alan Henry, Batten; John Frederick, Heard (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  7. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  8. ^ a b c Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.{{citation}}: CS1 maint: unflagged free DOI (link)
  9. ^ a b Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
  10. ^ a b Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1): 1, Bibcode:1970CoAsi.239....1B.
  11. ^ "iot Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-07-30.{{cite web}}: CS1 maint: postscript (link)
  12. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  13. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on February 22, 2012, retrieved 2012-01-16
  14. ^ Lefèvre, L.; et al. (November 2009), "A systematic study of variability among OB-stars based on HIPPARCOS photometry", Astronomy and Astrophysics, 507 (2): 11411201, Bibcode:2009A&A...507.1141L, doi:10.1051/0004-6361/200912304
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