Delta Pictoris
Location of δ Pictoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pictor
Right ascension 06h 10m 17.908s[1]
Declination −54° 58′ 07.11″[1]
Apparent magnitude (V) 4.72[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type B1/2(III)n[4] (B0.5:III?np + B0.5/3:)[5]
U−B color index −1.00[6]
B−V color index −0.229±0.008[2]
Variable type β Lyr[7] + β Cep[8]
Astrometry
Radial velocity (Rv)+30.6±2.8[9] km/s
Proper motion (μ) RA: −4.90 mas/yr[1]
Dec.: +7.41 mas/yr[1]
Parallax (π)2.51 ± 0.15 mas[1]
Distance1,300 ± 80 ly
(400 ± 20 pc)
Absolute magnitude (MV)−3.27[2]
Orbit[10]
Period (P)1.67254 d
Semi-major axis (a)≥ 3.83 Gm (0.0256 AU)
Eccentricity (e)0.050±0.17
Periastron epoch (T)2,438,500.79±0.09 JD
Argument of periastron (ω)
(secondary)		90±18°
Semi-amplitude (K1)
(primary)		167.0±2.8 km/s
Details
Primary
Mass16.3[11] M☉
Radius7.62[11] R☉
Luminosity20,900[11] L☉
Temperature25,200[11] K
Rotational velocity (v sin i)170[8] km/s
Secondary
Mass8.6[11] M☉
Radius5.05[11] R☉
Luminosity4,790[11] L☉
Temperature21,400[11] K
Other designations
δ Pic, del Pic, FK5 235, GC 7898, HD 42933, HIP 29276, HR 2212, SAO 234359[12]
Database references
SIMBADdata

Delta Pictoris, Latinized from δ Pictoris, is a binary star system in the southern constellation Pictor. It is visible to the naked with a combined apparent visual magnitude of 4.72.[2] The system is located at a distance of approximately 1,300 light years from the Sun based on parallax measurements,[1] and is drifting further away with a radial velocity of ~31 km/s.[9] It is a runaway star system that is generating a bow shock as it moves through the interstellar medium.[13]

A light curve for Delta Pictoris, plotted from TESS data[14]

The binary nature of this system was discovered by R. E. Wilson in 1914,[10] then it was found to be variable by A. W. J. Cousins in 1951.[15] A. D. A. Thackeray published orbital elements for the pair in 1966, showing they form an eclipsing double-lined spectroscopic binary with an orbital period of 1.67 days in essentially a circular orbit.[10] The low inclination of the orbital plane results in shallow eclipses.[3] The system is classified as a likely Beta Lyrae-type eclipsing binary with a peak magnitude of 4.65, which drops to 4.90 during the primary eclipse and 4.83 in the secondary eclipse.[7] It is probably a detached binary system with no circumstellar material being found.[3]

Both components of this system are massive main sequence stars[3] with a combined stellar classification of B1/2(III)n.[4] One member of the pair displays β Cep type pulsational behavior.[8] Mass estimates give a primary with 16.3 times the mass of the Sun and a secondary with about half that.[11]

References

  1. 1 2 3 4 5 6 Van Leeuwen, F. (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. Vizier catalog en try
  2. 1 2 3 4 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. Vizier catalog entry
  3. 1 2 3 4 Eaton, J. A.; Wu, C. -C. (May 1983). "ANS spectrophotometry : delta Pictoris as an upper-main-sequence Algol system". Publications of the Astronomical Society of the Pacific. 95: 319–324. Bibcode:1983PASP...95..319E. doi:10.1086/131165. S2CID 122266645.
  4. 1 2 Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
  5. ↑ Balona, L. A.; et al. (May 2019). "Rotational modulation in TESS B stars". Monthly Notices of the Royal Astronomical Society. 485 (3): 3457–3469. arXiv:1902.09470. Bibcode:2019MNRAS.485.3457B. doi:10.1093/mnras/stz586.
  6. ↑ Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
  7. 1 2 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 255195566.
  8. 1 2 3 Pedersen, May G.; et al. (February 2019). "Diverse Variability of O and B Stars Revealed from 2-minute Cadence Light Curves in Sectors 1 and 2 of the TESS Mission: Selection of an Asteroseismic Sample". The Astrophysical Journal Letters. 872 (1): 11. arXiv:1901.07576. Bibcode:2019ApJ...872L...9P. doi:10.3847/2041-8213/ab01e1. S2CID 118963697. L9.
  9. 1 2 Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications. 30: 57. Bibcode:1967IAUS...30...57E.
  10. 1 2 3 Thackeray, A. D. (1966). "The spectroscopic binary δ Pictoris". Monthly Notices of the Royal Astronomical Society. 131 (3): 435. Bibcode:1966MNRAS.131..435T. doi:10.1093/mnras/131.3.435.
  11. 1 2 3 4 5 6 7 8 9 Malkov, Oleg Yu (February 2020). "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes". Monthly Notices of the Royal Astronomical Society. 491 (4): 5489–5497. Bibcode:2020MNRAS.491.5489M. doi:10.1093/mnras/stz3363.
  12. ↑ "del Pic". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-01-26.{{cite web}}: CS1 maint: postscript (link)
  13. ↑ Noriega-Crespo, Alberto; et al. (February 1997). "Bow Shocks Around Runaway Stars. III. The High Resolution Maps". Astronomical Journal. 113: 780–786. Bibcode:1997AJ....113..780N. doi:10.1086/118298.
  14. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  15. ↑ Cousins, A. W. J. (October 1951). "Bright variable stars in southern hemisphere (first list)". The Observatory. 71: 199–201. Bibcode:1951Obs....71..199C.
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