HD 74389

HD 74389
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
HD 74389 A
Right ascension 08h 45m 46.92304s[1]
Declination +48° 52′ 43.5507″[1]
Apparent magnitude (V) 7.48[2]
HD 74389 B
Right ascension 08h 45m 46.92304s[3]
Declination +48° 52′ 43.5507″[3]
Apparent magnitude (V) 14.62[2]
Characteristics
Spectral type A2V + DA1.3 + M?[2]
U−B color index +0.05[4]
B−V color index +0.07[4]
Astrometry
HD 74389 A
Radial velocity (Rv)−15.4[5] km/s
Proper motion (μ) RA: −2.097±0.096[1] mas/yr
Dec.: 8.067±0.076[1] mas/yr
Parallax (π)7.6401 ± 0.0633 mas[1]
Distance427 ± 4 ly
(131 ± 1 pc)
Absolute magnitude (MV)1.2[2]
HD 74389 B
Proper motion (μ) RA: −1.437±0.089[3] mas/yr
Dec.: 7.605±0.075[3] mas/yr
Parallax (π)7.6689 ± 0.0729 mas[3]
Distance425 ± 4 ly
(130 ± 1 pc)
Absolute magnitude (MV)9.4[2]
Orbit[6]
Period (P)80,000 yr
Semi-major axis (a)2488.5 AU
Details
A
Mass1.71[6] M☉
Luminosity9.71[7] L☉
Temperature8.200[7] K
B
Mass0.69[6] M☉
Radius0.015[2] R☉
Luminosity0.4[2] L☉
Surface gravity (log g)7.85[2] cgs
Temperature39,500[6] K
Other designations
BD+49°1766, HIP 42994, TYC 3420-1971-1, GSC 03420-01971, 2MASS J08454693+4852435[8]
Database references
SIMBADdata

HD 74389 is a double star system approximately 425 light years from Earth. The primary, HD 74389 A, was initially listed in the Hipparcos catalog as an A0V spectral type star, but this was subsequently updated in 1990 as A2V when Sanduleak and Pesch imaged it with the Burrell Schmidt telescope at Kitt Peak.[9]

The primary component is a white A-type main sequence star with an apparent magnitude of +7.48. Its furthest companion, HD 74389 B, is a DA-type white dwarf located 20.11 arcseconds west of—at least 190 AU from—HD 74389 A, and has a V magnitude of 14.62.

On August 4, 2016, NASA's Goddard Space Flight Center announced that its citizen science program, Disk Detective, discovered a debris disk orbiting the primary, making this the first disk ever discovered around a star with a companion white dwarf.[10] Cataloged as DDOI AWI00000wz, the disk temperature was observed to be at most 136 K. Although stars with white dwarf companions are common, and there are three known planetary systems with white dwarfs as distant companions (Gl 86, HD 27442, and HD 147513), no debris disks had previously been discovered with a closely associated white dwarf.[11]

  1. ^ a b c d e Cite error: The named reference Gaia DR2 for A was invoked but never defined (see the help page).
  2. ^ a b c d e f g h Cite error: The named reference bergeron was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Gaia DR2 for B was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference ubv was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference rv was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference holberg was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference mcdonald 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. ^ Sanduleak, N.; Pesch, Peter (1990). "On a possible white-dwarf companion to HD 74389". Publications of the Astronomical Society of the Pacific. 102: 440. Bibcode:1990PASP..102..440S. doi:10.1086/132651.
  10. ^ Kuchner, Marc. "Our First Paper and the First Debris Disk with a White Dwarf Companion!" Web blog post. Disk Detective: A Zooniverse project blog. 4 August 2016.
  11. ^ Kuchner, Marc J.; Silverberg, Steven M.; Bans, Alissa S.; Bhattacharjee, Shambo; Kenyon, Scott J.; Debes, John H.; Currie, Thayne; Garcia, Luciano; Jung, Dawoon; Lintott, Chris; McElwain, Michael; Padgett, Deborah L.; Rebull, Luisa M.; Wisniewski, John P.; Nesvold, Erika; Schawinski, Kevin; Thaller, Michelle L.; Grady, Carol A.; Biggs, Joseph; Bosch, Milton; Cernohous, Tadeás; Luca, Hugo A. Durantini; Hyogo, Michiharu; Wah, Lily Lau Wan; Piipuu, Art; Piñeiro, Fernanda (19 July 2016). "Disk Detective: Discovery of New Circumstellar Disk Candidates through Citizen Science". The Astrophysical Journal. 830 (2): 84. arXiv:1607.05713. Bibcode:2016ApJ...830...84K. doi:10.3847/0004-637X/830/2/84. S2CID 28650844.