9 Andromedae

This article is about the star. For the galaxy, see Andromeda IX.
9 Andromedae

A light curve for AN Andromedae, plotted from TESS data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 23h 18m 23.32202s[2]
Declination +41° 46′ 25.2031″[2]
Apparent magnitude (V) 5.98[3]
Characteristics
Spectral type A7 V[4] or A7m[3]
B−V color index 0.215±0.002[3]
Variable type β Lyr[5]
Astrometry
Radial velocity (Rv)−3.8±2.9[3] km/s
Proper motion (μ) RA: −10.266[2] mas/yr
Dec.: −9.791[2] mas/yr
Parallax (π)7.0976 ± 0.0544 mas[2]
Distance460 ± 4 ly
(141 ± 1 pc)
Absolute magnitude (MV)0.43[3]
Orbit[6]
Period (P)3.2196 d
Eccentricity (e)0.03
Inclination (i)60.2[7]°
Periastron epoch (T)2,436,094.876 JD
Semi-amplitude (K1)
(primary)		71.6 km/s
Details[7]
9 And A
Mass2.48 M☉
Radius3.51 R☉
Luminosity49.2 L☉
Temperature8,200 K
Rotational velocity (v sin i)81[8] km/s
9 And B
Mass1.32 M☉
Luminosity17.5 L☉
Temperature6,330 K
Other designations
9 And, AN And, BD+40° 5043, HD 219815, HIP 115065, HR 8864, SAO 52881, PPM 64041[9]
Database references
SIMBADdata

9 Andromedae, abbreviated 9 And by convention, is a variable binary star system in the northern constellation Andromeda. 9 Andromedae is the Flamsteed designation, while it bears the variable star designation AN Andromedae, or AN And. The maximum apparent visual magnitude of the system is 5.98,[3] which places it near the lower limit of visibility to the human eye. Based upon an annual parallax shift of 7.1 mas,[2] it is located 460 light years from the Earth.

This system was determined to be a single-lined spectroscopic binary in 1916 by American astronomer W. S. Adams, and the initial orbital elements were computed by Canadian astronomer R. K. Young in 1920.[7] The pair orbit each other with a period of 3.2196 days and an eccentricity of 0.03.[6] It is an eclipsing binary, which means the orbital plane is inclined close to the line of sight and, from the perspective of the Earth, the stars pass in front of each other, causing two partial eclipses every orbit. During the transit of the secondary in front of the primary, the visual magnitude drops to 6.16, while the eclipse of the secondary by the primary lowers the net magnitude to 6.09.[10]

  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 c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Hill1975 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference gcvs was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Pourbaix2004 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Tremko1978 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Royer2002 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Avvakumova2013 was invoked but never defined (see the help page).