HD 4778

HD 4778

A light curve for GO Andromedae, plotted from TESS data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 50m 18.26563s[2]
Declination +45° 00′ 08.1439″[2]
Apparent magnitude (V) 6.13[3]
Characteristics
Spectral type A3VpSiSrCrEuKsn[4]
B−V color index 0.043±0.004[3]
Variable type α2 CVn[5]
Astrometry
Radial velocity (Rv)1.60[6] km/s
Proper motion (μ) RA: 65.353[2] mas/yr
Dec.: 4.133[2] mas/yr
Parallax (π)9.3224 ± 0.0916 mas[2]
Distance350 ± 3 ly
(107 ± 1 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 9.32 mas.[2]

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.

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference abt1995 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Samus2017 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Kharchenko was invoked but never defined (see the help page).
  7. ^ a b c d e f g Cite error: The named reference aaa334_181 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference Perraut_et_al_2020 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference David2015 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Panek1980 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Bohlender1989 was invoked but never defined (see the help page).