Epsilon Delphini

ε Delphini
Location of ε Delphini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Delphinus
Right ascension 20h 33m 12.77192s[1]
Declination +11° 18′ 11.7412″[1]
Apparent magnitude (V) 4.03[2] (3.95−4.05)[3]
Characteristics
Spectral type B6 III[4]
U−B color index −0.46[2]
B−V color index −0.13[2]
Variable type suspected[3]
Astrometry
Radial velocity (Rv)−19.4±0.7[5] km/s
Proper motion (μ) RA: +11.96[1] mas/yr
Dec.: −28.97[1] mas/yr
Parallax (π)9.87 ± 0.21 mas[1]
Distance330 ± 7 ly
(101 ± 2 pc)
Absolute magnitude (MV)−0.06[6]
Details
Radius4.6[7] R☉
Luminosity676[8] L☉
Surface gravity (log g)3.71±0.09[9] cgs
Temperature13,614±15[7] K
Metallicity [Fe/H]+0.08±0.10[9] dex
Rotational velocity (v sin i)52±4[10] km/s
Age220[6] Myr
Other designations
Aldulfin, ε Del, 2 Del, BD+10° 4321, FK5 768, HD 195810, HIP 101421, HR 7852, SAO 106230[11]
Database references
SIMBADdata

Epsilon Delphini (ε Delphini, abbreviated Eps Del, ε Del), officially named Aldulfin /ælˈdʌlfən/,[12] is a solitary,[13] blue-white hued star in the northern constellation of Delphinus. It is visible to the naked eye with an apparent visual magnitude of 4.03.[2] Based upon an annual parallax shift of 9.87 mas as seen from the Earth,[1] the system is located about 330 light-years from the Sun. At Epsilon Delphini's distance, the visual magnitude is diminished by an extinction factor of 0.11 due to interstellar dust.[6] The star is moving closer to the Sun with a radial velocity of −19 km/s.[5]

This is a B-type giant star with a stellar classification of B6 III.[4] It has 4.6[7] times the Sun's radius and is radiating 676[8] times the solar luminosity from its photosphere at an effective temperature of 13,614 K.[7] The star may be slightly variable, occasionally brightening to magnitude 3.95.[3] It is spinning with a projected rotational velocity of 52 km/s.[10]

  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 Crawford1971 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Lesh1968 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Gontcharov2012 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference mnras189_601 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Wu2011 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Bailey2013 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ "Naming Stars". IAU.org. Retrieved 16 December 2017.
  13. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).