View source for Delta Pavonis

{{Short description|Star in the constellation Pavo}}
{{Starbox begin}}
{{Starbox image
 | image=
   {{Location mark
     | image=Pavo constellation map.svg
     | float=center | width=250 | position=right
     | mark=Red circle.svg | mark_width=8 | mark_link=δ Pavonis
     | x%=39.0 | y%=48.0
   }}
 | caption=Location of δ Pavonis (circled)
}}
{{Starbox observe
 | epoch       = J2000
 | constell    = [[Pavo (constellation)|Pavo]]
 | ra          = {{RA|20|08|43.60887}}<ref name=GaiaDR3/>
 | dec         = {{DEC|−66|10|55.4428}}<ref name=GaiaDR3/>
 | appmag_v    = 3.56<ref name=rob64/>
}}
{{Starbox character
 | class       = G8&nbsp;IV<ref name=aj132_1_161/>
 | b-v         = 0.76<ref name=rob64/>
 | u-b         = 0.45<ref name="rob64"/>
 | variable    = ''Suspected''<ref name="Ruban2006"/>
}}
{{Starbox astrometry
 | radial_v    = {{val|−23.52|0.81}}<ref name=Bailer2018/>
 | prop_mo_ra  = +1,211.761
 | prop_mo_dec = –1,130.237
 | pm_footnote = <ref name=GaiaDR3/>
 | parallax    = 163.9544
 | p_error     = 0.1222
 | parallax_footnote = <ref name=GaiaDR3/>
 | absmag_v    = 4.62<ref name=cgssn09/>
}}
{{Starbox detail
 | source      = <ref name=Rains2020/>
 | mass        = 1.051{{±|0.062}}<ref name=Pinheiro_et_al_2014/>
 | radius      = {{val|1.197|0.016}}
 | gravity     = {{val|4.26|0.06}}
 | luminosity  = {{val|1.24|0.03}}
 | temperature = {{val|5571|48|fmt=commas}}
 | metal_fe    = {{val|0.33|0.03}}
 | rotation    = {{val|21.4|9.3|ul=d}}<ref name="Laliotis2023"/>
 | rotational_velocity = 0.32
 | age_gyr     = 6.6–6.9<ref name=apj687_2/>&nbsp;Gyr<br>9.3<ref name=cgssn09/> 
}}
{{Starbox catalog
 | names = {{odlist | B=δ Pav | CD=-66&nbsp;2367 | GCTP=4754 | GJ=780 | HD=190248 | HIP=99240 | HR=7665 | LHS=485 | LTT=7946 | LFT=1520 | NSV=12790 | SAO=254733|2MASS=J20084376-6610563}}<ref name="SIMBAD"/>
}}
{{Starbox reference
 | Simbad=Del+Pav
}}
{{Starbox end}}

'''Delta Pavonis''', [[Romanization of Greek|Latinized]] from δ Pavonis, is a single<ref name=Fuhrmann2017/> [[star]] in the southern [[constellation]] of [[Pavo (constellation)|Pavo]]. It has an [[apparent visual magnitude]] of 3.56,<ref name=SIMBAD/> making it a fourth-magnitude star that is visible to the naked eye from the southern hemisphere. [[Stellar parallax|Parallax]] measurements yield an estimated distance of {{Convert|19.89|ly|pc|abbr=off|lk=on}} from [[Earth]].<ref name=GaiaDR3/> This makes it one of the [[List of nearest bright stars|nearest bright stars]] to the Solar System. It is approaching the Sun with a [[radial velocity]] of −23.5&nbsp;km/s, and is predicted to come as close as {{convert|5.4693|pc|ly|1|disp=out|abbr=off}} in around 49,200&nbsp;years.<ref name=Bailer2018/>

==Observations==
This object is a [[subgiant]] of [[spectral type]] G8&nbsp;IV; it will stop [[nuclear fusion|fusing]] [[hydrogen]] at its [[stellar core|core]] relatively soon, starting the process of becoming a [[red giant]]. Hence, Delta Pavonis is 24% brighter than the Sun, but the [[effective temperature]] of its [[stellar atmosphere|outer atmosphere]] is less: 5,571&nbsp;K.<ref name=Rains2020/> Its mass is 105% of [[solar mass|Sol's mass]], with a mean radius 120% of [[solar radius|Sol's radius]]. Delta Pavonis's surface [[convection zone]] extends downward to about 43.1% of the star's radius, but only contains 4.8% of the star's mass.<ref name=takeda08/>

Spectroscopic examination of Delta Pavonis shows that it has a higher abundance of elements heavier than [[helium]] ([[metallicity]]) than does the Sun. This value is typically given in terms of the ratio of [[iron]] (chemical symbol Fe) to hydrogen (H) in a star's atmosphere, relative to that in Sol's atmosphere (iron being a good proxy for the presence of other heavy elements). The metallicity of Delta Pavonis is approximately

:<math>\begin{smallmatrix}\left [ \frac{Fe}{H} \right ]\ =\ 0.33\end{smallmatrix}</math>

This notation gives the [[logarithm]] of the iron-to-hydrogen ratio, relative to that of the Sun, meaning that Delta Pavonis's iron abundance is 214% of that of Sol. It is considered super metal-rich, and the high metallicity has slowed its [[stellar evolution|evolution]].<ref name=Mello/> Studies have shown a correlation between abundant heavy elements in stars, and the presence of a planetary system,<ref name=aaa458_3/> so Delta Pavonis has a greater than average probability of harboring planets.<ref name=Mello/>

The age of Delta Pavonis is approximately 6.6 to 6.9&nbsp;billion years,<ref name=apj687_2/> and is certainly in the {{val|5|to|7}}&nbsp;billion year range.<ref name=Mello/> It appears to be rotating slowly, with a [[projected rotational velocity]] of 0.32&nbsp;kilometers per second.<ref name=Rains2020/>

==Possible planetary system==
The existence of a Jupiter-mass gas giant on a long-period orbit around Delta Pavonis is suspected, as of 2021, based on [[astrometry|astrometric]] data.<ref name="MakarovZacharias2021"/> A study in 2023 detected a trend in the star's radial velocity, which may indicate the presence of a planetary companion, supporting the previous astrometric result. Such a planet would, at minimum, orbit with a period of 37 years at a distance of {{val|11.1|ul=AU}}, and have a mass at least {{val|69|ul=Earth mass}} ({{Jupiter mass|0.22|link=y}}).<ref name="Laliotis2023"/>

{{OrbitboxPlanet begin|name = Delta Pavonis|table_ref=<ref name="Laliotis2023"/>}}
{{Orbitbox planet hypothetical
| exoplanet = 
| mass_earth = ≥69
| semimajor = ≥11.1
| period = ≥13,500
| eccentricity = 
| inclination = 
}}
{{Orbitbox end}}

==SETI==
Delta Pavonis has been identified by Maggie Turnbull and [[Jill Tarter]] of the [[SETI Institute]] as the "Best [[SETI]] target" among the  100 closest [[G-type star]]s. Properties in its favor include a high metallicity, minimal level of [[stellar magnetic field|magnetic activity]], low rotation rate, and kinematic membership in the [[thin disk population]] of the [[Milky Way]]. [[Gas giant]]s orbiting in, near, or through a star's [[habitable zone]] may destabilize the orbits of terrestrial planets in that zone; the lack of detected [[radial velocity]] variation suggests that there are no such gas giants orbiting Delta Pavonis. However, observation has detected no artificial radio sources.<ref name=apj149_2/> Delta Pavonis, a close [[Photometry (astronomy)|photometric]] match to the Sun, is the nearest [[solar analog]] that is not a member of a binary or multiple [[star system]].<ref name=Mello/>

==References==
{{reflist|refs=

<ref name=GaiaDR3>{{Cite Gaia DR3|6427464123776727168}}</ref>

<ref name=Fuhrmann2017>{{cite journal
 | title=Multiplicity among Solar-type Stars
 | last1=Fuhrmann | first1=K. | last2=Chini | first2=R.
 | last3=Kaderhandt | first3=L. | last4=Chen | first4=Z.
 | display-authors=1 | journal=The Astrophysical Journal
 | volume=836 | issue=1 | id=139 | pages=23 | date=February 2017
 | bibcode=2017ApJ...836..139F | doi=10.3847/1538-4357/836/1/139 | doi-access=free }}</ref>

<ref name=Bailer2018>{{cite journal
 | title=New stellar encounters discovered in the second Gaia data release
 | last1=Bailer-Jones | first1=C.A.L. | last2=Rybizki | first2=J 
 | last3=Andrae | first3=R. | last4=Fouesnea | first4=M.
 | display-authors=1 | journal=Astronomy & Astrophysics
 | volume=616 | pages=A37 | date=2018
 | arxiv=1805.07581 | bibcode=2018A&A...616A..37B
 | doi=10.1051/0004-6361/201833456 | s2cid=56269929 }}</ref>

<ref name=Rains2020>{{cite journal
 | title=Precision angular diameters for 16 southern stars with VLTI/PIONIER
 | display-authors=1 | last1=Rains | first1=Adam D.
 | last2=Ireland | first2=Michael J. | last3=White | first3=Timothy R.
 | last4=Casagrande | first4=Luca | last5=Karovicova | first5=I.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=493 | issue=2 | pages=2377–2394 | date=April 2020
 | arxiv=2004.02343 | bibcode=2020MNRAS.493.2377R 
 | doi=10.1093/mnras/staa282 | doi-access=free }}</ref>

<ref name=SIMBAD>{{cite web | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+190248 | title=NSV 12790 -- Variable Star | work=SIMBAD | publisher=[[Centre de Données astronomiques de Strasbourg]] | access-date=2009-08-21 }}</ref>

<ref name=rob64>{{cite journal | first=A. W. J. | last=Cousins |author2=Stoy, R. H. | title=Photoelectric magnitudes and colours of Southern stars | journal=Royal Observatory Bulletin | year=1962 | volume=64 | pages=103–248 |bibcode = 1962RGOB...64..103C }}</ref>

<ref name=takeda08>{{cite journal |author1=Takeda, G. |author2=Ford, E. B. |author3=Sills, A. |author4=Rasio, F. A. |author5=Fischer, D. A. |author6=Valenti, J. A.  | title=Stellar parameters of nearby cool stars (Takeda+, 2007) |date=November 2008 | bibcode=2008yCat..21680297T | volume=216 | pages=80297 | journal=VizieR On-line Data Catalog |doi=10.26093/cds/vizier.21680297 |id= J/ApJS/168/297. Originally Published in: 2007ApJS..168..297T }}</ref>

<ref name=apj687_2>{{cite journal | last1=Mamajek | first1=Eric E. | last2=Hillenbrand | first2=Lynne A. | title=Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics | journal=The Astrophysical Journal | volume=687 | issue=2 | pages=1264–1293 |date=November 2008 | doi=10.1086/591785 | bibcode=2008ApJ...687.1264M |arxiv = 0807.1686 | s2cid=27151456 }}</ref>

<ref name=aaa458_3>{{cite journal | author=Sousa, S.G. | title=Spectroscopic parameters for a sample of metal-rich solar-type stars | journal=Astronomy and Astrophysics | year=2006 | volume=458 | issue=3 | pages=873–880 | bibcode=2006A&A...458..873S | doi=10.1051/0004-6361:20065658 | display-authors=1 | last2=Santos | first2=N. C. | last3=Israelian | first3=G. | last4=Mayor | first4=M. | last5=Monteiro | first5=M. J. P. F. G. | doi-access=free }}</ref>

<ref name=apj149_2>{{cite journal |author1=M.C. Turnbull |author2=J.C. Tarter | title=Target Selection for SETI. II. Tycho-2 Dwarfs, Old Open Clusters, and the Nearest 100 Stars | journal=The Astrophysical Journal Supplement Series | year=2003 | volume=149 | issue=2 | pages=423–436 | bibcode=2003ApJS..149..423T | doi=10.1086/379320 | doi-access=free }}</ref>

<ref name=Mello>{{cite journal |author=G. F. Porto de Mello |author2=E. F. del Peloso |author3=L. Ghezzi | title=Astrobiologically interesting stars within 10 parsecs of the Sun | journal=Astrobiology | year=2006 | volume=6 | issue=2 | pages=308–331 | doi= 10.1089/ast.2006.6.308 | pmid=16689649 | arxiv=astro-ph/0511180 | bibcode=2006AsBio...6..308P|s2cid=119459291 }}</ref>

<ref name=aj132_1_161>{{citation
 | display-authors=1
 | last1=Gray | first1=R. O.
 | last2=Corbally | first2=C. J.
 | last3=Garrison | first3=R. F.
 | last4=McFadden | first4=M. T.
 | last5=Bubar | first5=E. J.
 | last6=McGahee | first6=C. E.
 | last7=O'Donoghue | first7=A. A.
 | last8=Knox | first8=E. R.
 | title=Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample
 | journal=[[The Astronomical Journal]]
 | volume=132 | issue=1 | pages=161–170 | date=July 2006
 | doi=10.1086/504637
 | bibcode=2006AJ....132..161G
 | arxiv=astro-ph/0603770
 | s2cid=119476992 | postscript=.
}}</ref>

<ref name=cgssn09>{{citation
 | last1=Holmberg | first1=J.
 | last2=Nordström | first2=B.
 | last3=Andersen | first3=J.
 | title=The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics
 | journal=Astronomy and Astrophysics
 | volume=501 | issue=3 |date=July 2009 | pages=941–947
 | doi=10.1051/0004-6361/200811191
 | bibcode=2009A&A...501..941H
 | arxiv=0811.3982
 | s2cid=118577511
 | postscript=.
}}</ref>

<ref name="Ruban2006">{{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 }}</ref>

<ref name="MakarovZacharias2021">{{cite journal
 | title=Looking for Astrometric Signals below 20 m/s: A Candidate Exo-Jupiter in δ Pav
 | last1=Makarov | first1=Valeri V. | last2=Zacharias | first2=Norbert
 | last3=Finch | first3=Charles T. | display-authors=1
 | journal=Research Notes of the AAS
 | volume=5|issue=5|year=2021|pages=108
 | issn=2515-5172 | doi=10.3847/2515-5172/abfec9 | doi-access=free
 | arxiv=2105.03244 | bibcode=2021RNAAS...5..108M}}</ref>

<ref name=Pinheiro_et_al_2014>{{citation
 | title=On the mass estimation for FGK stars: comparison of several methods
 | last1=Pinheiro | first1=F. J. G. | last2=Fernandes | first2=J. M.
 | last3=Cunha | first3=M. S. | last4=Monteiro | first4=M. J. P. F. G.
 | last5=Santos | first5=N. C. | last6=Sousa | first6=S. G.
 | last7=Marques | first7=J. P. | last8=Fang | first8=J. -J.
 | last9=Mortier | first9=A. | last10=Sousa | first10=J.
 | display-authors=1 | postscript=.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=445 | issue=3 | pages=2223–2231 | date=December 2014
 | doi=10.1093/mnras/stu1812 | bibcode=2014MNRAS.445.2223P | doi-access=free | hdl=10316/80294 | hdl-access=free }}</ref>

<ref name="Laliotis2023">{{cite journal |last1=Laliotis |first1=Katherine |last2=Burt |first2=Jennifer A. |display-authors=etal |date=February 2023 |title=Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions |journal=[[The Astronomical Journal]] |volume= 165|issue= 4|page=176 |doi= 10.3847/1538-3881/acc067|arxiv=2302.10310|bibcode=2023AJ....165..176L |s2cid=257050346 |doi-access=free }}</ref>

}} <!-- END: refs= -->

==Further reading==
{{Div col|small=yes}}
*{{citation | postscript=.
 | title=The carbon abundance and colours of Delta Pavonis
 | last=Bell | first=R. A.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=162 | page=37 | year=1973
 | doi=10.1093/mnras/162.1.37 | bibcode=1973MNRAS.162...37B | doi-access=free}}
*{{citation | postscript=.
 | title=The composition of delta Pavonis
 | display-authors=1 | last1=Harmer | first1=D. L.
 | last2=Pagel | first2=B. E. J. | last3=Powell | first3=A. L. T.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=150 | page=409 | year=1970
 | doi=10.1093/mnras/150.4.409 | bibcode=1970MNRAS.150..409H | doi-access=free }}
*{{citation | postscript=.
 | title=The composition and age of δ Pavonis
 | last=Rodgers | first=A. W.
 | journal=Monthly Notices of the Royal Astronomical Society
 | volume=145 | page=151 | year=1969
 | issue=2
 | doi=10.1093/mnras/145.2.151 | bibcode=1969MNRAS.145..151R | doi-access=free}}
{{Div col end}}

==External links==
* {{cite web
 | title=Delta Pavonis
 | work=SolStation
 | url=http://www.solstation.com/stars/dpavonis.htm
 | access-date=November 3, 2005
}}

{{Sky|20|08|43.6084|-|66|10|55.446|19.89}}
{{Nearest systems|4}}
{{Stars of Pavo}}

{{DEFAULTSORT:Delta Pavonis}}
<!-- Properties -->
[[Category:G-type subgiants]]
[[Category:Solar-type stars|Pavonis, Delta]]
[[Category:Suspected variables]]
[[Category:Hypothetical planetary systems]]
<!-- Location/catalogues -->
[[Category:Pavo (constellation)]]
[[Category:2MASS objects|J20084376-6610563]]
[[Category:Bayer objects|Pavonis, Delta]]
[[Category:Bright Star Catalogue objects|7665]]
[[Category:Durchmusterung objects|CD-66 2367]]
[[Category:Gliese and GJ objects|0780]]
[[Category:Henry Draper Catalogue objects|190248]]
[[Category:Hipparcos objects|099240]]