Delta Pyxidis

Delta Pyxidis
Location of δ Pyxidis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pyxis
Right ascension 08h 55m 31.56948s[1]
Declination −27° 40′ 54.7315″[1]
Apparent magnitude (V) +4.877[2]
Characteristics
Spectral type A3 IV[3]
U−B color index +0.224[2]
B−V color index +0.130[2]
Astrometry
Radial velocity (Rv)5.4±0.8[4] km/s
Proper motion (μ) RA: +81.90[1] mas/yr
Dec.: −100.43[1] mas/yr
Parallax (π)13.19 ± 0.77 mas[1]
Distance250 ± 10 ly
(76 ± 4 pc)
Absolute magnitude (MV)+0.67[5]
Details
Mass1.84[6] M☉
Radius1.6[7] R☉
Luminosity59[3] L☉
Surface gravity (log g)3.77±0.14[6] cgs
Temperature8,609±293[6] K
Rotational velocity (v sin i)68[6] km/s
Age296[6] Myr
Other designations
δ Pyx, CPD−27° 3497, HD 76483, HIP 43825, HR 3556, SAO 176697, WDS J08555-2741A[8]
Database references
SIMBADdata

Delta Pyxidis (δ Pyxidis) is binary star[9] system in southern constellation of Pyxis. Having an apparent visual magnitude of +4.877,[2] it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 13.19 mas as seen from Earth,[1] it is located around 250 light years from the Sun.

In Chinese, 天狗 (Tiān Gǒu), meaning Celestial Dog, refers to an asterism consisting of δ Pyxidis, e Velorum, f Velorum, β Pyxidis, α Pyxidis and γ Pyxidis. Consequently, δ Pyxidis itself is known as 天狗七 (Tiān Gǒu qī, English: the Seventh Star of Celestial Dog.)[10]

This is an astrometric binary system, as determined by changes in the proper motion of the primary.[11] The visible component has a stellar classification of A3 IV,[3] indicating it has the spectrum of an A-type subgiant star that is consuming the last of the hydrogen at its core. At the age of around 296 million years,[6] it is 92.5%[3] of the way through its main sequence lifetime and is spinning with a projected rotational velocity of 68 km/s.[6] The star has an estimated 1.8[6] times the mass of the Sun and about 1.6[7] times the Sun's radius. It is radiating 59[3] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,609 K.[6]

  1. ^ a b c d e f 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 sps1966 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ a b c d e f g h i Cite error: The named reference David2015 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference PasinettiFracassini2001 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日
  11. ^ Cite error: The named reference Frankowski2007 was invoked but never defined (see the help page).