HD 4778

HD 4778

A light curve for GO Andromedae, plotted from TESS data
Observation data
Epoch J2000      Equinox ICRS
Constellation Andromeda
Right ascension 00h 50m 18.26532s
Declination +45° 00′ 08.1355″
Apparent magnitude (V) 6.13
Characteristics
Evolutionary stage main sequence
Spectral type A3VpSiSrCrEuKsn
B−V color index 0.043±0.004
Variable type α2 CVn
Astrometry
Radial velocity (Rv)1.60 km/s
Proper motion (μ) RA: +65.570 mas/yr
Dec.: +4.662 mas/yr
Parallax (π)9.6184±0.0488 mas
Distance339 ± 2 ly
(104.0 ± 0.5 pc)
Absolute magnitude (MV)1.18
Details
Mass2.24±0.09 M☉
Radius2.36±0.12 R☉
Luminosity34.9±4.3 L☉
Surface gravity (log g)4.12±0.09 cgs
Temperature9,135±400 K
Rotation2.5616 days
Rotational velocity (v sin i)33 km/s
Age77 Myr
Other designations
GO Andromedae, BD+44° 176, FK5 2055, HD 4778, HIP 3919, HR 234, SAO 36702, PPM 43369
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. The star is located 350 light years away, as determined from its annual parallax shift of 9.62 mas.

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

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

References

  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.