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// Workers AI · dad joke modeWhat did HD 4778 say to its star friend? You're a big disk-covery.

From Wikipedia, the free encyclopedia
(Redirected from GO Andromedae)
HD 4778

A light curve for GO Andromedae, plotted from TESS data[1]
Observation data
Epoch J2000      Equinox ICRS
Constellation Andromeda[2]
Right ascension 00h 50m 18.26532s[3]
Declination +45° 00′ 08.1355″[3]
Apparent magnitude (V) 6.13[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A3VpSiSrCrEuKsn[4]
B−V color index 0.043±0.004[2]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)1.60[6] km/s
Proper motion (μ) RA: +65.570[3] mas/yr
Dec.: +4.662[3] mas/yr
Parallax (π)9.6184±0.0488 mas[3]
Distance339 ± 2 ly
(104.0 ± 0.5 pc)
Absolute magnitude (MV)1.18[7]
Details
Mass2.24±0.09[7] M☉
Radius2.36±0.12[8] R☉
Luminosity34.9±4.3[8] L☉
Surface gravity (log g)4.12±0.09[7] cgs
Temperature9,135±400[8] K
Rotation2.5616[7] days
Rotational velocity (v sin i)33[4] km/s
Age77[9] Myr
Other designations
GO Andromedae, BD+44° 176, FK5 2055, HD 4778, HIP 3919, HR 234, SAO 36702, PPM 43369[10]
Database references
SIMBADdata

HD 4778, also known as HR 234 and GO Andromedae, is a variable star in the constellation Andromeda. Its magnitude varies by 0.04 magnitudes from the median of 6.12 with a period of approximately 2.55 days.[11] The star is located 350 light years away, as determined from its annual parallax shift of 9.62 mas.[3]

This is an Ap star with a stellar classification of A3VpSiSrCrEuKsn,[4] showing chemical peculiarities in its spectrum from strontium, chromium, and europium.[12] It is an Alpha2 Canum Venaticorum variable[5] with a magnetic field that varies across the range +1,400 to −1,100 G.[13] This rotation-modulated variability allows direct determination of the rotation rate of 2.5616 days.[7]

HD 4778 has 2.24[7] times the mass of the Sun and 2.36[8] times the Sun's radius. The star is radiating 35[8] times the Sun's luminosity from its photosphere at an effective temperature of 9,375 K.[7] It is about 77[9] million years old.

References

[edit]
  1. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. 1 2 3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
  3. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  5. 1 2 Samus, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General Catalogue of Variable Stars". Astronomy Reports. GCVS 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  6. ↑ Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID 119323941.
  7. 1 2 3 4 5 6 7 North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286, Bibcode:1998A&A...334..181N
  8. 1 2 3 4 5 Perraut, K.; et al. (October 2020), "Benchmarking the fundamental parameters of Ap stars with optical long-baseline interferometric measurements", Astronomy & Astrophysics, 642: 13, Bibcode:2020A&A...642A.101P, doi:10.1051/0004-6361/202038753, A101.
  9. 1 2 David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
  10. ↑ "HD 3167". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 6, 2018.
  11. ↑ VSX (4 January 2010). "GO Andromedae". AAVSO Website. American Association of Variable Star Observers. Retrieved 25 May 2014.
  12. ↑ Panek, R. J. (October 1980). "Periodic spectral variability of the AP star HR 234". Astronomy and Astrophysics. 90 (3): 341–343. Bibcode:1980A&A....90..341P.
  13. ↑ Bohlender, D. A. (August 1989). "The magnetic field and rotation period of the AP star HD 4778". Astronomy and Astrophysics. 220: 215–217. Bibcode:1989A&A...220..215B.
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