HD 74389

HD 74389 is a hierarchical triple 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]

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[1] mas
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[3] mas
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[8]
Database references
SIMBADdata

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]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Liebert, James; Bergeron, P.; Saffer, Rex A. (October 1990). "Atmospheric parameters of the white-dwarf companion to HD 74389". Publications of the Astronomical Society of the Pacific. 102: 1126. Bibcode:1990PASP..102.1126L. doi:10.1086/132741.
  3. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  4. Oja, T. (1986). "UBV photometry of stars whose positions are accurately known. III". Astronomy and Astrophysics Supplement Series. 65: 405. Bibcode:1986A&AS...65..405O.
  5. Grenier, S.; Baylac, M.-O.; Rolland, L.; Burnage, R.; Arenou, F.; Briot, D.; Delmas, F.; Duflot, M.; Genty, V.; Gómez, A. E.; Halbwachs, J.-L.; Marouard, M.; Oblak, E.; Sellier, A. (1999). "Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS" (PDF). Astronomy and Astrophysics Supplement. 137 (3): 451. Bibcode:1999A&AS..137..451G. doi:10.1051/aas:1999489.
  6. Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; Barstow, M. A.; Burleigh, M. R. (2013). "Where are all the Sirius-like binary systems?". Monthly Notices of the Royal Astronomical Society. 435 (3): 2077. arXiv:1307.8047. Bibcode:2013MNRAS.435.2077H. doi:10.1093/mnras/stt1433.
  7. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
  8. "HD 74389". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-13.
  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.
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