Delta Pavonis: Difference between revisions

Coordinates: Sky map 20h 08m 43.6084s, −66° 10′ 55.446″
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{{Short description|Star in the constellation Pavo}}
{{Starbox begin
{{Starbox begin}}
| name=Delta Pavonis
}}
{{Starbox image
{{Starbox image
| image ={{Location map|100x100
| image=
{{Location mark
|AlternativeMap=Pavo IAU.svg
| image=Pavo constellation map.svg
|caption=
| float=center | width=250 | position=right
|alt=Diagram showing star positions and boundaries of the Pavo constellation and its surroundings
| mark=Red circle.svg | mark_width=8 | mark_link=δ Pavonis
|width=250
|lat=50.9 |long=43.3
| x%=39.0 | y%=48.0
}}
|mark=Cercle rouge 100%.svg | marksize=12
| caption=Location of δ Pavonis (circled)
|float=center
}}| caption=Location of δ Pavonis (circled)
}}
}}
{{Starbox observe
{{Starbox observe
| epoch=J2000
| epoch = J2000
| constell=[[Pavo (constellation)|Pavo]]
| constell = [[Pavo (constellation)|Pavo]]
| ra={{RA|20|08|43.60953}}<ref name=aaa474_2_653/>
| ra = {{RA|20|08|43.60887}}<ref name=GaiaDR3/>
| dec={{DEC|−66|10|55.4436}}<ref name=aaa474_2_653/>
| dec = {{DEC|−66|10|55.4428}}<ref name=GaiaDR3/>
| appmag_v=3.56<ref name=rob64/>
| appmag_v = 3.56<ref name=rob64/>
}}
}}
{{Starbox character
{{Starbox character
| class=G8&nbsp;IV<ref name=aj132_1_161/>
| class = G8&nbsp;IV<ref name=aj132_1_161/>
| b-v=0.76<ref name=rob64/>
| b-v = 0.76<ref name=rob64/>
| u-b=0.45<ref name="rob64"/>
| u-b = 0.45<ref name="rob64"/>
| variable=''Suspected''<ref name="Ruban2006"/>
| variable = ''Suspected''<ref name="Ruban2006"/>
}}
}}
{{Starbox astrometry
{{Starbox astrometry
| radial_v={{val|−21.7|0.9}}<ref name=rgcrv/>
| radial_v = {{val|−23.52|0.81}}<ref name=Bailer2018/>
| prop_mo_ra=+1,211.03<ref name=aaa474_2_653/>
| prop_mo_ra = +1,211.761
| prop_mo_dec=–1,130.05<ref name=aaa474_2_653/>
| prop_mo_dec = –1,130.237
| pm_footnote = <ref name=GaiaDR3/>
| parallax=163.71
| parallax = 163.9544
| p_error=0.17
| p_error = 0.1222
| parallax_footnote=<ref name=aaa474_2_653/>
| absmag_v=4.62<ref name=cgssn09/>
| parallax_footnote = <ref name=GaiaDR3/>
| absmag_v = 4.62<ref name=cgssn09/>
}}
}}
{{Starbox detail
{{Starbox detail
| mass=0.991<ref name=takeda08/>
| source = <ref name=Rains2020/>
| radius=1.22<ref name=takeda08/>
| mass = 1.051{{±|0.062}}<ref name=Pinheiro_et_al_2014/>
| radius = {{val|1.197|0.016}}
| gravity=4.26<ref name=aaa487/>
| gravity = {{val|4.26|0.06}}
| luminosity={{nowrap|1.22 ± 0.04}}<ref name=mnras405_3_1907/>
| luminosity = {{val|1.24|0.03}}
| temperature=5,604<ref name=aaa487/>
| temperature = {{val|5571|48|fmt=commas}}
| metal_fe=+0.33<ref name=aaa487/>
| metal_fe = {{val|0.33|0.03}}
| rotational_velocity=1.0<ref name=mnras405_3_1907/>
| rotation = {{val|21.4|9.3|ul=d}}<ref name="Laliotis2023"/>
| age_gyr=6.6–6.9<ref name=apj687_2/>&nbsp;Gyr<br>9.3<ref name=cgssn09/>
| rotational_velocity = 0.32
| age_gyr = 6.6–6.9<ref name=apj687_2/>&nbsp;Gyr<br>9.3<ref name=cgssn09/>
}}
}}
{{Starbox catalog
{{Starbox catalog
| names = [[Cape Photographic Durchmusterung|CD]]-66&nbsp;2367, [[General Catalogue of Trigonometric Parallaxes|GCTP]]&nbsp;4754, [[Gliese-Jahreiss catalogue|GJ]]&nbsp;780, [[Henry Draper catalogue|HD]]&nbsp;190248, [[Hipparcos Catalogue|HIP]]&nbsp;99240, [[Harvard Revised catalogue|HR]]&nbsp;7665, [[Luyten Half-Second catalogue|LHS]]&nbsp;485, [[Luyten Two-Tenths catalogue|LTT]]&nbsp;7946, LFT&nbsp;1520, [[New Catalogue of Suspected Variable Stars|NSV]]&nbsp;12790, [[Smithsonian Astrophysical Observatory|SAO]]&nbsp;254733.<ref name="SIMBAD"/>
| 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
{{Starbox reference
|Simbad=Del+Pav
| Simbad=Del+Pav
}}
}}
{{Starbox end}}
{{Starbox end}}

'''Delta Pavonis''' (δ Pav, δ Pavonis) is a [[star]] in the southern [[circumpolar 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. [[Parallax]] measurements from the [[Hipparcos]] satellite yield an estimated distance of {{Convert|19.92|ly|pc|abbr=off|lk=on}} from [[Earth]].<ref name=aaa474_2_653/> This makes it one of the [[List of nearest bright stars|nearest bright stars]] to the Solar System.
'''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==
==Observations==
It is a [[subgiant]] of [[spectral type]] G8&nbsp;IV, meaning it is about to stop [[nuclear fusion|fusing]] [[hydrogen]] in its core and is starting the process of becoming a [[red giant]]. Because of that, Delta Pavonis is 22%<ref name=mnras405_3_1907/> brighter than the Sun even though the [[effective temperature]] of its [[stellar atmosphere|outer atmosphere]] is lower, at 5,604&nbsp;K.<ref name=aaa487/> It has 99.1% of the [[solar mass|Sun's mass]] and 122% of the [[solar radius|Sun's radius]]. The 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/>
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 this star shows that it has a higher abundance of elements heavier than [[helium]] (or [[metallicity]], as astronomers call it) than does the Sun. This value is typically given in terms of the relative ratio of [[iron]] (chemical symbol Fe) to hydrogen (H) as compared to the Sun's atmosphere (iron being a relatively easy element to detect in a stellar atmosphere). For Delta Pavonis,
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
the metallicity is about:


:<math>\begin{smallmatrix}\left [ \frac{Fe}{H} \right ]\ =\ 0.33\end{smallmatrix}</math>
:<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 the Sun.) This corresponds to a 214% abundance of iron in this star's atmosphere compared to the solar abundance. Past studies have shown a correlation between the heavy element abundance in stars and the presence of a planetary system,<ref name=aaa458_3/> suggesting Delta Pavonis has a greater than average probability of harboring planets. However, no planetary companions have yet been discovered in orbit around this star.<ref name=Mello/>
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 this star is in the range of 6.6–6.9 billion years old,<ref name=apj687_2/> and the star's luminosity has increased 60% since it was a zero-age main-sequence star.{{citation needed|date=March 2012}} It appears to be rotating slowly with a [[projected rotational velocity]] of 1.0&nbsp;km s<sup>−1</sup>.<ref name=mnras405_3_1907/>
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/>


==Search for planets==
==SETI==
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"/>
It has been identified by Maggie Turnbull and [[Jill Tarter]] of the [[SETI Institute]] as the "Best [[SETI]] target" among the list of the 100 nearest [[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]]. The lack of detected [[radial velocity]] variation suggests that there are no [[gas giant]]s orbiting near the star's [[habitable zone]], which may otherwise destabilize a hypothetical Earth-like planet in that orbital zone. As of 1999, no radio source of technological origin has been detected coming from this star.<ref name=apj149_2/> Delta Pavonis is the nearest [[solar analog]] that is not a member of a binary or multiple [[star system]]. This is a type of star that is a close [[Photometry (astronomy)|photometric]] match to the Sun.<ref name=Mello/>


==In fiction==
==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/>
* [[Delta Pavonis in fiction]]


==References==
==References==
{{reflist|2|refs=
{{reflist|refs=


<ref name=GaiaDR3>{{Cite Gaia DR3|6427464123776727168}}</ref>
<ref name=aaa474_2_653>{{citation | last1=van Leeuwen | first1=F. | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 |date=November 2007 | pages=653–664 | doi=10.1051/0004-6361:20078357 | bibcode=2007A&A...474..653V | arxiv=0708.1752 }}</ref>


<ref name=Fuhrmann2017>{{cite journal
<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 | accessdate=2009-08-21 }}</ref>
| 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
<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>
| 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
<ref name=takeda08>{{cite journal | author=Takeda, G.; Ford, E. B.; Sills, A.; Rasio, F. A.; Fischer, D. A.; Valenti, J. A. | title=Stellar parameters of nearby cool stars (Takeda+, 2007) |date=November 2008 | bibcode=2008yCat..21680297T | last2=Ford | last3=Sills | last4=Rasio | last5=Fischer | last6=Valenti | volume=216 | pages=80297 | journal=VizieR On-line Data Catalog |id= J/ApJS/168/297. Originally published in: 2007ApJS..168..297T }}</ref>
| 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 }}</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=aaa487>{{cite journal | author=Sousa, S. G. | title=Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes | journal=Astronomy and Astrophysics | volume=487 | issue=1 |date=August 2008 | pages=373–381 | doi=10.1051/0004-6361:200809698 | bibcode=2008A&A...487..373S | display-authors=1 | last2=Santos | first2=N. C. | last3=Mayor | first3=M. | last4=Udry | first4=S. | last5=Casagrande | first5=L. | last6=Israelian | first6=G. | last7=Pepe | first7=F. | last8=Queloz | first8=D. | last9=Monteiro | first9=M. J. P. F. G. |arxiv = 0805.4826 }} See [[VizieR]] catalogue [http://vizier.cfa.harvard.edu/viz-bin/VizieR?-source=J/A+A/487/373 J/A+A/487/373].</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=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 }}</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=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. }}</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=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 }}</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=Mello>{{cite journal | author=G. F. Porto de Mello, E. F. del Peloso, 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}}</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=mnras405_3_1907>{{citation | display-authors=1 | last1=Bruntt | first1=H. | last2=Bedding | first2=T. R. | last3=Quirion | first3=P.-O. | last4=Lo Curto | first4=G. | last5=Carrier | first5=F. | last6=Smalley | first6=B. | last7=Dall | first7=T. H. | last8=Arentoft | first8=T. | last9=Bazot | first9=M. | title=Accurate fundamental parameters for 23 bright solar-type stars | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=405 | issue=3 | pages=1907–1923 |date=July 2010 | doi=10.1111/j.1365-2966.2010.16575.x | bibcode=2010MNRAS.405.1907B |arxiv = 1002.4268 }}</ref>


<ref name=aj132_1_161>{{citation
<ref name=aj132_1_161>{{citation
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| bibcode=2006AJ....132..161G
| bibcode=2006AJ....132..161G
| arxiv=astro-ph/0603770
| arxiv=astro-ph/0603770
| postscript=.
| s2cid=119476992 | postscript=.
}}</ref>

<ref name=rgcrv>{{citation
| last=Evans | first=D. S.
| date=June 20–24, 1966
| editor1-last=Batten | editor1-first=Alan Henry
| editor2-last=Heard | editor2-first=John Frederick
| title=The Revision of the General Catalogue of Radial Velocities
| work=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30
| location=University of Toronto
| publisher=International Astronomical Union
| bibcode=1967IAUS...30...57E
| postscript=.
}}</ref>
}}</ref>


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| bibcode=2009A&A...501..941H
| bibcode=2009A&A...501..941H
| arxiv=0811.3982
| arxiv=0811.3982
| s2cid=118577511
| postscript=.
| postscript=.
}}</ref>
}}</ref>
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| doi=10.1134/S1063773706090052
| doi=10.1134/S1063773706090052
| bibcode=2006AstL...32..604R
| bibcode=2006AstL...32..604R
}}</ref>
| 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= -->
}} <!-- 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==
==External links==
Line 165: Line 224:
| work=SolStation
| work=SolStation
| url=http://www.solstation.com/stars/dpavonis.htm
| url=http://www.solstation.com/stars/dpavonis.htm
| accessdate=November 3, 2005
| access-date=November 3, 2005
}}
}}


{{Sky|20|08|43.6084|-|66|10|55.446|19.91}}
{{Sky|20|08|43.6084|-|66|10|55.446|19.89}}
{{Nearest systems|4}}
{{Nearest systems|4}}
{{Stars of Pavo}}
{{Stars of Pavo}}


[[Category:Bayer objects|Pavonis, Delta]]
{{DEFAULTSORT:Delta Pavonis}}
<!-- Properties -->
[[Category:Henry Draper Catalogue objects|190248]]
[[Category:Hipparcos objects|099240]]
[[Category:HR objects|7665]]
[[Category:Pavo (constellation)]]
[[Category:Suspected variables]]
[[Category:G-type subgiants]]
[[Category:G-type subgiants]]
[[Category:Solar-type stars|Pavonis, Delta]]
[[Category:Solar-type stars|Pavonis, Delta]]
[[Category:Durchmusterung objects]]
[[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:Gliese and GJ objects|0780]]
[[Category:Henry Draper Catalogue objects|190248]]
[[Category:Hipparcos objects|099240]]

Latest revision as of 10:51, 4 January 2024

Delta Pavonis
Location of δ Pavonis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pavo
Right ascension 20h 08m 43.60887s[1]
Declination −66° 10′ 55.4428″[1]
Apparent magnitude (V) 3.56[2]
Characteristics
Spectral type G8 IV[3]
U−B color index 0.45[2]
B−V color index 0.76[2]
Variable type Suspected[4]
Astrometry
Radial velocity (Rv)−23.52±0.81[5] km/s
Proper motion (μ) RA: +1,211.761 mas/yr[1]
Dec.: –1,130.237 mas/yr[1]
Parallax (π)163.9544 ± 0.1222 mas[1]
Distance19.89 ± 0.01 ly
(6.099 ± 0.005 pc)
Absolute magnitude (MV)4.62[6]
Details[7]
Mass1.051±0.062[8] M☉
Radius1.197±0.016 R☉
Luminosity1.24±0.03 L☉
Surface gravity (log g)4.26±0.06 cgs
Temperature5,571±48 K
Metallicity [Fe/H]0.33±0.03 dex
Rotation21.4±9.3 d[9]
Rotational velocity (v sin i)0.32 km/s
Age6.6–6.9[10] Gyr
9.3[6] Gyr
Other designations
δ Pav, NSV 12790, CD−66 2367, GJ 780, HD 190248, HIP 99240, HR 7665, SAO 254733, LFT 1520, LHS 485, LTT 7946, 2MASS J20084376-6610563[11]
Database references
SIMBADdata

Delta Pavonis, Latinized from δ Pavonis, is a single[12] star in the southern constellation of Pavo. It has an apparent visual magnitude of 3.56,[11] making it a fourth-magnitude star that is visible to the naked eye from the southern hemisphere. Parallax measurements yield an estimated distance of 19.89 light-years (6.10 parsecs) from Earth.[1] This makes it one of the nearest bright stars to the Solar System. It is approaching the Sun with a radial velocity of −23.5 km/s, and is predicted to come as close as 17.8 light-years in around 49,200 years.[5]

Observations[edit]

This object is a subgiant of spectral type G8 IV; it will stop fusing hydrogen at its 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 outer atmosphere is less: 5,571 K.[7] Its mass is 105% of Sol's mass, with a mean radius 120% of 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.[13]

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

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 evolution.[14] Studies have shown a correlation between abundant heavy elements in stars, and the presence of a planetary system,[15] so Delta Pavonis has a greater than average probability of harboring planets.[14]

The age of Delta Pavonis is approximately 6.6 to 6.9 billion years,[10] and is certainly in the 5 to 7 billion year range.[14] It appears to be rotating slowly, with a projected rotational velocity of 0.32 kilometers per second.[7]

Search for planets[edit]

The existence of a Jupiter-mass gas giant on a long-period orbit around Delta Pavonis is suspected, as of 2021, based on astrometric data.[16] 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 11.1 AU, and have a mass at least 69 M🜨 (0.22 MJ).[9]

SETI[edit]

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 stars. Properties in its favor include a high metallicity, minimal level of magnetic activity, low rotation rate, and kinematic membership in the thin disk population of the Milky Way. Gas giants 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.[17] Delta Pavonis, a close photometric match to the Sun, is the nearest solar analog that is not a member of a binary or multiple star system.[14]

References[edit]

  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c Cousins, A. W. J.; Stoy, R. H. (1962). "Photoelectric magnitudes and colours of Southern stars". Royal Observatory Bulletin. 64: 103–248. Bibcode:1962RGOB...64..103C.
  3. ^ Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
  4. ^ Ruban, E. V.; et al. (September 2006), "Spectrophotometric observations of variable stars", Astronomy Letters, 32 (9): 604–607, Bibcode:2006AstL...32..604R, doi:10.1134/S1063773706090052, S2CID 121747360
  5. ^ a b Bailer-Jones, C.A.L.; et al. (2018). "New stellar encounters discovered in the second Gaia data release". Astronomy & Astrophysics. 616: A37. arXiv:1805.07581. Bibcode:2018A&A...616A..37B. doi:10.1051/0004-6361/201833456. S2CID 56269929.
  6. ^ a b Holmberg, J.; Nordström, B.; Andersen, J. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
  7. ^ a b c Rains, Adam D.; et al. (April 2020). "Precision angular diameters for 16 southern stars with VLTI/PIONIER". Monthly Notices of the Royal Astronomical Society. 493 (2): 2377–2394. arXiv:2004.02343. Bibcode:2020MNRAS.493.2377R. doi:10.1093/mnras/staa282.
  8. ^ Pinheiro, F. J. G.; et al. (December 2014), "On the mass estimation for FGK stars: comparison of several methods", Monthly Notices of the Royal Astronomical Society, 445 (3): 2223–2231, Bibcode:2014MNRAS.445.2223P, doi:10.1093/mnras/stu1812, hdl:10316/80294.
  9. ^ a b Laliotis, Katherine; Burt, Jennifer A.; et al. (February 2023). "Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions". The Astronomical Journal. 165 (4): 176. arXiv:2302.10310. Bibcode:2023AJ....165..176L. doi:10.3847/1538-3881/acc067. S2CID 257050346.
  10. ^ a b Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785. S2CID 27151456.
  11. ^ a b "NSV 12790 -- Variable Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2009-08-21.
  12. ^ Fuhrmann, K.; et al. (February 2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal. 836 (1): 23. Bibcode:2017ApJ...836..139F. doi:10.3847/1538-4357/836/1/139. 139.
  13. ^ Takeda, G.; Ford, E. B.; Sills, A.; Rasio, F. A.; Fischer, D. A.; Valenti, J. A. (November 2008). "Stellar parameters of nearby cool stars (Takeda+, 2007)". VizieR On-line Data Catalog. 216: 80297. Bibcode:2008yCat..21680297T. doi:10.26093/cds/vizier.21680297. J/ApJS/168/297. Originally Published in: 2007ApJS..168..297T.
  14. ^ a b c d G. F. Porto de Mello; E. F. del Peloso; L. Ghezzi (2006). "Astrobiologically interesting stars within 10 parsecs of the Sun". Astrobiology. 6 (2): 308–331. arXiv:astro-ph/0511180. Bibcode:2006AsBio...6..308P. doi:10.1089/ast.2006.6.308. PMID 16689649. S2CID 119459291.
  15. ^ Sousa, S.G.; et al. (2006). "Spectroscopic parameters for a sample of metal-rich solar-type stars". Astronomy and Astrophysics. 458 (3): 873–880. Bibcode:2006A&A...458..873S. doi:10.1051/0004-6361:20065658.
  16. ^ Makarov, Valeri V.; et al. (2021). "Looking for Astrometric Signals below 20 m/s: A Candidate Exo-Jupiter in δ Pav". Research Notes of the AAS. 5 (5): 108. arXiv:2105.03244. Bibcode:2021RNAAS...5..108M. doi:10.3847/2515-5172/abfec9. ISSN 2515-5172.
  17. ^ M.C. Turnbull; J.C. Tarter (2003). "Target Selection for SETI. II. Tycho-2 Dwarfs, Old Open Clusters, and the Nearest 100 Stars". The Astrophysical Journal Supplement Series. 149 (2): 423–436. Bibcode:2003ApJS..149..423T. doi:10.1086/379320.

Further reading[edit]

External links[edit]


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