Delta Scuti,Latinizedfrom δ Scuti, is avariable starin the southernconstellationScutum.With anapparent visual magnitudethat fluctuates around 4.72,[4]it is thefifth-brightest starin this small and otherwise undistinguished constellation. Analysis of theparallaxmeasurements place this star at a distance of about 199light-years(61parsecs) from Earth.[1]It is drifting closer with aradial velocityof −45 km/s.[5]
  | |
| Observation data EpochJ2000EquinoxJ2000 | |
|---|---|
| Constellation | Scutum |
| Right ascension | 18h42m16.42705s[1] |
| Declination | −09° 03′ 09.2004″[1] |
| Apparent magnitude(V) | 4.60 - 4.79[2] |
| Characteristics | |
| Spectral type | F2 IIIp[3] |
| U−Bcolor index | +0.16[4][2] |
| B−Vcolor index | +0.35[4] |
| Variable type | δ Sct[2] |
| Astrometry | |
| Radial velocity(Rv) | −45.1±0.6[5]km/s |
| Proper motion(μ) | RA:7.175[1]mas/yr Dec.:1.996[1]mas/yr |
| Parallax(π) | 16.3644 ± 0.2022mas[1] |
| Distance | 199 ± 2ly (61.1 ± 0.8pc) |
| Absolute magnitude(MV) | 0.72±0.04[6] |
| Details | |
| Mass | 2.23+0.06 −0.05[7]M☉ |
| Radius | 4.78±0.38[1]R☉ |
| Luminosity | 40.0±0.6[1]L☉ |
| Surface gravity(logg) | 3.5[8]cgs |
| Temperature | 6,638+277 −247[1]K |
| Metallicity[Fe/H] | 0.41[6]dex |
| Rotational velocity(vsini) | 25.5[8]km/s |
| Age | 0.7±0.1[6]Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Variability
edit
In 1900,William W. CampbellandWilliam H. Wrightused the Mills spectrograph at theLick Observatoryto determine that this star has a variable radial velocity.[11]The 0.19377 days (4.650 h) period of this variability as well as 0.2 magnitude changes in luminosity demonstrated in 1935 that the variability was intrinsic, rather than being the result of aspectroscopic binary.[12]In 1938, a secondary period was discovered and a pulsation theory was proposed to model the variation.[13]Since then, observation of Delta Scuti has shown that it pulsates in multiple discrete radial and non-radial modes. The strongest mode has a frequency of 59.731 μHz, the next strongest has a frequency of 61.936 μHz, and so forth, with a total of eight different frequency modes now modeled.[14]
Delta Scuti is the prototype of theDelta Scuti typevariable stars.It is a high-amplitude δ Scuti type pulsator with light variations of about 0.19 magnitudes (V).[15]The peculiar chemical abundances of this star are similar to those ofAm stars.[8]It has astellar classificationof F2 IIIp,[3]matching anF-typegiant star.Delta Scuti has 2.2[7]times the mass and 4.8[1]times the radius of the Sun. It is approximately 700 million years old and is spinning with aprojected rotational velocityof 25.5 km/s.[8]On average, the star is radiating 40 times the luminosity of the Sun from itsphotosphereat aneffective temperatureof 6,638 K.[1]
Space velocity
editThespace velocitycomponents of this star in thegalactic coordinate systemare[U, V, W]=[−42, −17, −1] km·s−1.It is following an orbit through theMilky Waygalaxy that has aneccentricityof 0.11, carrying it as close as 22.31kly(6.84kpc) to, and as far as 27.59 kly (8.46 kpc) from theGalactic Center.[6]If Delta Scuti maintains its current movement and brightness, it will pass within 10 light-years of the Solar System,[16]becoming the brightest star in the sky between1150000and1330000CE.It will reach an apparent magnitude of −1.84, brighter than the current −1.46 ofSirius.[17][18]
Optical companions
editThis star has two optical companions. The first is a +12.2 magnitude star that is 15.2arcsecondsfrom Delta Scuti. The second is a +9.2 magnitude star that is 53 arcseconds away.[19]Both are distant background stars unrelated to Delta Scuti.[20]
Nomenclature
editFlamsteed did not recognise the constellation Scutum and included several of its stars inAquila.δ Scuti was catalogued as2 Aquilae.TheBayer designationδ was assigned by Gould rather than Bayer.[21]
References
edit- ^abcdefghijkBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData Release 2: Summary of the contents and survey properties ".Astronomy & Astrophysics.616.A1.arXiv:1804.09365.Bibcode:2018A&A...616A...1G.doi:10.1051/0004-6361/201833051.Gaia DR2 record for this sourceatVizieR.
- ^abcSamus, 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.
- ^abCowley, Anne; Fraquelli, Dorothy (February 1974)."MK Spectral Types for Some Bright F Stars".Publications of the Astronomical Society of the Pacific.86(509): 7.Bibcode:1974PASP...86...70C.doi:10.1086/129562.
- ^abcJohnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars".Communications of the Lunar and Planetary Laboratory.4(99): 99.Bibcode:1966CoLPL...4...99J.
- ^abGontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system".Astronomy Letters.32(11): 759–771.arXiv:1606.08053.Bibcode:2006AstL...32..759G.doi:10.1134/S1063773706110065.S2CID119231169.
- ^abcdHolmberg, 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.S2CID118577511.
- ^abNordström, B.; et al. (May 2004). "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs".Astronomy and Astrophysics.418:989–1019.arXiv:astro-ph/0405198.Bibcode:2004A&A...418..989N.doi:10.1051/0004-6361:20035959.S2CID11027621.
- ^abcdYushchenko, A.; et al. (May 2005)."The chemical composition of δ Scuti".Monthly Notices of the Royal Astronomical Society.359(55): 865–873.Bibcode:2005MNRAS.359..865Y.doi:10.1111/j.1365-2966.2005.08921.x.
- ^"del Sct – Variable star of delta Sct type".SIMBAD Astronomical Object Database.Centre de Données astronomiques de Strasbourg.Retrieved2009-10-23.
- ^"Light Curve".Hipparcos ESA.ESA.Retrieved31 August2022.
- ^Campbell, W. W.; Wright, W. H. (1900)."A list of nine stars whose velocities in the line of sight are variable".Astrophysical Journal.12:254–257.Bibcode:1900ApJ....12..254C.doi:10.1086/140765.Listed as 2 Scuti on p. 256.
- ^Colacevich, A. (August 1935)."On the variable radial velocity of δ Scuti".Publications of the Astronomical Society of the Pacific.47(278): 231–232.Bibcode:1935PASP...47..231C.doi:10.1086/124599.
- ^Sterne, T. E. (March 1938). "The Secondary Variation of δ Scuti".Astrophysical Journal.87:133–150.Bibcode:1938ApJ....87..133S.doi:10.1086/143913.
- ^Templeton, Matthew R.; et al. (October 1997). "A New Pulsation Spectrum and Asteroseismology of delta Scuti".The Astronomical Journal.114:1592–1601.Bibcode:1997AJ....114.1592T.doi:10.1086/118590.
- ^"del Sct".International Variable Star Index.AAVSO.Retrieved29 August2022.
- ^García-Sánchez, J.; et al. (2001)."Stellar encounters with the solar system".Astronomy and Astrophysics.379(2): 634–659.Bibcode:2001A&A...379..634G.doi:10.1051/0004-6361:20011330.
- ^Sky and Telescope,April 1998 (p60), based on computations fromHipparcosmission data.
- ^Tomkin, Jocelyn (April 1998). "Once and Future Celestial Kings".Sky and Telescope.95(4): 59–63.Bibcode:1998S&T....95d..59T.– based on computations fromHIPPARCOSdata. (The calculations exclude stars whose distance orproper motionis uncertain.)PDF[permanent dead link]
- ^Burnham, Robert (1978).Burnham's celestial handbook: an observer's guide to the universe beyond the solar system.Vol. 3.Courier Dover Publications.p.1746.ISBN0-486-23673-0.
- ^Vallenari, A.; et al. (Gaia collaboration) (2023)."GaiaData 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.S2CID244398875.
- ^Wagman, M. (August 1987). "Flamsteed's Missing Stars".Journal for the History of Astronomy.18(3): 212.Bibcode:1987JHA....18..209W.doi:10.1177/002182868701800305.S2CID118445625.