View source for HD 170384

{{Short description|A-type dwarf; Corona Australis}}
{{Starbox begin
| name = [[Henry Draper Catalogue|HD]] 170384
}}
{{Starbox image
| image = {{Location mark
| width = 280
| image = Corona Australis constellation map.svg
| float = center |position = right
| mark = Red circle.svg | mark_width = 8 | mark_link = HD 170384
| x = 547 | y = 432
}}
| caption = Location of HD 170384 (circled)
}}
{{Starbox observe
| epoch = [[J2000.0]] ([[International Celestial Reference System|ICRS]])
| constell = [[Corona Australis]]
| ra = {{RA|18|31|02.94877}}<ref name = GaiaDR3/>
| dec = {{DEC|−41|54|49.8025}}<ref name = GaiaDR3/>
| appmag_v = 6.02{{±|0.01}}<ref name = Tycho2000/>
}}
{{Starbox character
| type = [[main sequence star]]<ref name = Zorec2012/>
| class = A3 V<ref name = Houk1978/>
| b-v = +0.14<ref name = Corben1971/>
}}
{{Starbox astrometry
| radial_v = −11.4{{±|0.4}}<ref name = Gontcharov2006/>
| parallax = 14.2387
| p_error = 0.0341
| parallax_footnote = <ref name = GaiaDR3/>
| prop_mo_ra = −3.406
| prop_mo_dec = −31.578
| pm_footnote = <ref name = GaiaDR3/>
| absmag_v = +1.86<ref name = Anderson2012/>
}}
{{Starbox detail
| mass = 2.00<ref name = David2015/>
| radius = 1.91{{±|0.10}}<ref name = Kervella2004/>
| luminosity = 16.7{{±|1.1|1.0}}<ref name = Zorec2012/>
| gravity = 4.19{{±|0.08|0.07}}<ref name = Stassun2019/>
| temperature = 8,694<ref name = Balona2019/>
| metal_fe = −0.01<ref name = Gontcharov2012/>
| rotation = {{val|19.2|ul=hours}}<ref name = Reiners2004/>
| rotational_velocity = 127{{±|5}}<ref name = Reiners2004/>
| age_myr = 544<ref name = David2015/>
}}
{{Starbox catalog
| names = {{odlist|Gould = 11 G. Coronae Australis<ref name = Gould1879/>|HD = 170384|CD = −41°12871|CPD = −41°8697|GC = 25249|HIP = 90759|HR = 6931|SAO = 229080}}<ref name = SIMBAD/>
}}
{{Starbox reference
| Simbad = HR+6931
}}
{{Starbox end}}
'''HD 170384''', also known as '''HR 6931''' or rarely ''11 G. Coronae Australis'', is a solitary white-hued [[star]] located in the southern [[constellation]] [[Corona Australis]]. It has an [[apparent magnitude]] of 6.02,<ref name = Tycho2000/> making it barely visible to the [[naked eye]], even under ideal conditions. The object is located relatively close at a distance of  229.1 [[light-year]]s based on [[Gaia DR3]] [[parallax]] measurements<ref name = GaiaDR3/> and it is drifting closer with a heliocentric [[radial velocity]] of {{val|−11.4|ul=km/s}}.<ref name = Gontcharov2006/> At its current distance, HD 170384's brightness is diminished by [[interstellar extinction]] of 0.28 [[magnitude (astronomy)|magnitude]]s<ref name = Gontcharov2017/> and it has an [[absolute magnitude]] of +1.86.<ref name = Anderson2012/>
This object has a [[stellar classification]] of A3 V, indicating that it is an ordinary [[A-type main-sequence star]]. It has double the [[Sun's mass]]<ref name = David2015/> and 1.91 times the [[radius of the Sun]].<ref name = Kervella2004/> It radiates 16.7 times the [[luminosity of the Sun]]<ref name = Zorec2012/> from its [[photosphere]] at an [[effective temperature]] of {{val|8694|ul=K|fmt=commas}}.<ref name = Balona2019/> HD 170384 has a near solar [[metallicity]] at [Fe/H] = −0.01 (97% solar)<ref name = Gontcharov2012/> and it is estimated to be 544 [[million years]] old,<ref name = David2015/> having completed 45% of its [[main sequence]] lifetime.<ref name = Zorec2012/> Like many hot stars HD 170384 spins rapidly, having a [[projected rotational velocity]] of {{val|127|ul=km/s}} and an estimated [[rotation period]] of 19.2 [[hours]].<ref name = Reiners2004/>
==References==
{{reflist||refs=
<ref name = GaiaDR3>{{Cite DR3|6722943305221879296}}</ref>
<ref name = Tycho2000>{{cite journal | last1 = Høg | first1 = E. | last2 = Fabricius | first2 = C. | last3 = Makarov | first3 = V. V. | last4 = Urban | first4 = S. | last5 = Corbin | first5 = T. | last6 = Wycoff | first6 = G. | last7 = Bastian | first7 = U. | last8 = Schwekendiek | first8 = P. | last9 = Wicenec | first9 = A. | title = The Tycho-2 catalogue of the 2.5 million brightest stars | journal = Astronomy and Astrophysics | date = March 2000 | volume = 355 | pages = L27–L30 | s2cid = 17128864 | bibcode = 2000A&A...355L..27H | issn = 0004-6361}}</ref>
<ref name = Houk1978>{{cite book | last1 = Houk | first1 = Nancy | volume = 2 | title = Michigan catalogue of two-dimensional spectral types for the HD stars: Declinations −53° to −40° | year = 1978 | bibcode = 1978mcts.book.....H }}</ref>
<ref name = Gontcharov2006>{{cite journal | last1 = Gontcharov | first1 = G. A. | title = Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system | journal = Astronomy Letters | date = November 2006 | volume = 32 | issue = 11 | pages = 759–771 | issn = 1063-7737 | eissn = 1562-6873 | doi = 10.1134/S1063773706110065 | pmid = | bibcode = 2006AstL...32..759G | arxiv = 1606.08053 | s2cid = 119231169 }}</ref>
<ref name = Anderson2012>{{cite journal | last1 = Anderson | first1 = E. | last2 = Francis | first2 = Ch. | title = XHIP: An extended hipparcos compilation | journal = Astronomy Letters | date = May 2012 | volume = 38 | issue = 5 | pages = 331–346 | issn = 1063-7737 | eissn = 1562-6873 | doi = 10.1134/S1063773712050015 | bibcode = 2012AstL...38..331A | arxiv = 1108.4971| s2cid = 119257644}}</ref>
<ref name = Corben1971>{{cite journal |last1=Corben |first1=P. M. |title=Photoelectric Magnitudes and Colours for Bright Southern Stars |journal=Monthly Notes of the Astronomical Society of South Africa |date=April 1971 |volume=30 |issue=4 |pages=37 |issn=0024-8266 |bibcode=1971MNSSA..30...37C}}</ref>
<ref name = David2015>{{cite journal | last1 = David | first1 = Trevor J. | last2 = Hillenbrand | first2 = Lynne A. | title = The Ages of Early-type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal = The Astrophysical Journal | date = 12 May 2015 | volume = 804 | issue = 2 | page = 146 | eissn = 1538-4357 | doi = 10.1088/0004-637X/804/2/146 | bibcode = 2015ApJ...804..146D  | s2cid = 33401607 | arxiv = 1501.03154 | doi-access = free}}</ref>
<ref name = Reiners2004>{{cite journal | last1 = Reiners | first1 = A. | last2 = Royer | first2 = F. | title = First signatures of strong differential rotation in A-type stars | journal = Astronomy & Astrophysics | date = February 2004 | volume = 415 | issue = 1 | pages = 325–329 | issn = 0004-6361 | eissn = 1432-0746 | doi = 10.1051/0004-6361:20034175 | bibcode = 2004A&A...415..325R | s2cid = 15726297 | arxiv = astro-ph/0311341 | doi-access = free}}</ref>
<ref name = Kervella2004>{{cite journal | last1 = Kervella | first1 = P. | last2 = Thévenin | first2 = F. | last3 = Di Folco | first3 = E. | last4 = Ségransan | first4 = D. | title = The angular sizes of dwarf stars and subgiants | journal = Astronomy & Astrophysics | date = October 2004 | volume = 426 | issue = 1 | pages = 297–307 | issn = 0004-6361 | eissn = 1432-0746 | doi = 10.1051/0004-6361:20035930 | bibcode = 2004A&A...426..297K | arxiv = astro-ph/0404180 | doi-access = free}}</ref>
<ref name = Stassun2019>{{cite journal | display-authors = 1 | last1 = Stassun | first1 = Keivan G. | last2 = Oelkers | first2 = Ryan J. | last3 = Paegert | first3 = Martin | last4 = Torres | first4 = Guillermo | last5 = Pepper | first5 = Joshua | last6 = Lee | first6 = Nathan De | last7 = Collins | first7 = Kevin | last8 = Latham | first8 = David W. | last9 = Muirhead | first9 = Philip S. | last10 = Chittidi | first10 = Jay | last11 = Rojas-Ayala | first11 = Bárbara | last12 = Fleming | first12 = Scott W. | last13 = Rose | first13 = Mark E. | last14 = Tenenbaum | first14 = Peter | last15 = Ting | first15 = Eric B. | last16 = Kane | first16 = Stephen R. | last17 = Barclay | first17 = Thomas | last18 = Bean | first18 = Jacob L. | last19 = Brassuer | first19 = C. E. | last20 = Charbonneau | first20 = David | last21 = Ge | first21 = Jian | last22 = Lissauer | first22 = Jack J. | last23 = Mann | first23 = Andrew W. | last24 = McLean | first24 = Brian | last25 = Mullally | first25 = Susan | last26 = Narita | first26 = Norio | last27 = Plavchan | first27 = Peter | last28 = Ricker | first28 = George R. | last29 = Sasselov | first29 = Dimitar | last30 = Seager | first30 = S. | last31 = Sharma | first31 = Sanjib | last32 = Shiao | first32 = Bernie | last33 = Sozzetti | first33 = Alessandro | last34 = Stello | first34 = Dennis | last35 = Vanderspek | first35 = Roland | last36 = Wallace | first36 = Geoff | last37 = Winn | first37 = Joshua N. | title = The Revised ''TESS'' Input Catalog and Candidate Target List | journal = The Astronomical Journal | date = 9 September 2019 | volume = 158 | issue = 4 | page = 138 | eissn = 1538-3881 | doi = 10.3847/1538-3881/ab3467 | bibcode = 2019AJ....158..138S | arxiv = 1905.10694 | s2cid = 166227927 | hdl = 1721.1/124721 | hdl-access = free | doi-access = free}}</ref>
<ref name = Zorec2012>{{cite journal | last1 = Zorec | first1 = J. | last2 = Royer | first2 = F. | title = Rotational velocities of A-type stars IV: Evolution of rotational velocities | journal = Astronomy & Astrophysics | date = January 2012 | volume = 537 | page = A120 | issn = 0004-6361 | eissn = 1432-0746 | doi = 10.1051/0004-6361/201117691 | bibcode = 2012A&A...537A.120Z | arxiv = 1201.2052 | doi-access = free | s2cid = 55586789}}</ref>
<ref name = Balona2019>{{cite journal | last = Balona | first = L. A. | title = Evidence for spots on hot stars suggests major revision of stellar physics | journal = Monthly Notices of the Royal Astronomical Society | publisher = Oxford University Press (OUP) | volume = 490 | issue=2 | date=October 7, 2019 | issn = 0035-8711 | doi = 10.1093/mnras/stz2808 | s2cid = 203642124 | doi-access = free | pages = 2112–2116| arxiv = 1910.01584 }}</ref>
<ref name = Gontcharov2012>{{cite journal | last1 = Gontcharov | first1 = G. A. | title = Dependence of kinematics on the age of stars in the solar neighborhood | journal = Astronomy Letters | date = December 2012 | volume = 38 | issue = 12 | pages = 771–782 | issn = 1063-7737 | eissn = 1562-6873 | doi = 10.1134/S1063773712120031 | bibcode = 2012AstL...38..771G | arxiv = 1606.08814 | s2cid = 118345778}}</ref>
<ref name = SIMBAD>{{Cite simbad|title = HD 170384|access-date = June 5, 2023}}</ref>
<ref name = Gould1879>{{cite journal | last=Gould | first=Benjamin Apthorp | title=Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas | journal=Resultados del Observatorio Nacional Argentino | volume=1 | bibcode=1879RNAO....1.....G | year=1878 | page=}}</ref>
<ref name = Gontcharov2017>{{cite journal | last1 = Gontcharov | first1 = George A. | last2 = Mosenkov | first2 = Aleksandr V. | title = Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars | journal = Monthly Notices of the Royal Astronomical Society | date = 28 September 2017 | volume = 472 | issue = 4 | pages = 3805–3820 | issn = 0035-8711 | eissn = 1365-2966 | doi = 10.1093/mnras/stx2219 | bibcode = 2017MNRAS.472.3805G | arxiv = 1709.01160 | s2cid = 118879856 | doi-access = free}}</ref>
}}
{{Stars of Corona Australis}}
[[Category:A-type main-sequence stars]]
[[Category:Corona Australis]]
[[Category:Gould objects|Coronae Australis, 11]]
[[Category:Durchmusterung objects|CD-41 12871]]
[[Category:Henry Draper Catalogue objects|170384]]
[[Category:Hipparcos objects|090759]]
[[Category:Bright Star Catalogue objects|6931]]