Delta Pictoris

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]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Eaton_Wu_1983 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Houk1979 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Balona_et_al_2019 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference MermiliodUBV was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Samus_et_al_2017 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Pedersen_et_al_2019 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Evans1967 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Thackeray1966 was invoked but never defined (see the help page).
  11. ^ a b c d e f g h i Cite error: The named reference Malkov2020 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Noriega-Crespo_et_al_1997 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Cousins1951 was invoked but never defined (see the help page).