ADS 7251

ADS 7251
ADS 7251 is located in the constellation Ursa Major
ADS 7251 is located in the constellation Ursa Major
ADS 7251
Location of ADS 7251 in the constellation Ursa Major

Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
ADS 7251 A
Right ascension 09h 14m 22.7749s[1]
Declination +52° 41′ 11.792″[1]
Apparent magnitude (V) 7.64[2]
ADS 7251 B
Right ascension 09h 14m 24.6828s[3]
Declination +52h 41m 10.902s[3]
Apparent magnitude (V) 7.70[2]
Characteristics
ADS 7251 A (HD 79210)
Spectral type M0V[4]
Apparent magnitude (B) 9.05[2]
Apparent magnitude (G) 6.976[1]
Apparent magnitude (J) 4.89[a][5]
Apparent magnitude (H) 3.987[a][5]
Apparent magnitude (K) 3.99[a][5]
B−V color index +1.41[6]
J−H color index +0.90[b]
J−K color index +0.90[b]
ADS 7251 B (HD 79211)
Spectral type K7V[4]
Apparent magnitude (B) 9.04[2]
Apparent magnitude (G) 7.054[3]
Apparent magnitude (J) 4.779[a][5]
Apparent magnitude (H) 4.043[a][5]
Apparent magnitude (K) 4.14[a][5]
B−V color index +1.42[6]
J−H color index +0.74[b]
J−K color index +0.64[b]
Astrometry
ADS 7251 A (HD 79210)
Radial velocity (Rv)11.245±0.0007[1] km/s
Proper motion (μ) RA: −1,545.787(18)[1] mas/yr
Dec.: −569.053(18)[1] mas/yr
Parallax (π)157.8879 ± 0.0197 mas[1]
Distance20.657 ± 0.003 ly
(6.3336 ± 0.0008 pc)
Absolute magnitude (MV)8.637[7]
ADS 7251 B
Radial velocity (Rv)12.104±0.0008[3] km/s
Proper motion (μ) RA: −1,573.040(18)[3] mas/yr
Dec.: −659.906(19)[3] mas/yr
Parallax (π)157.8825 ± 0.0211 mas[3]
Distance20.658 ± 0.003 ly
(6.3338 ± 0.0008 pc)
Absolute magnitude (MV)8.712[7]
Orbit[8]
Period (P)975 yr
Semi-major axis (a)16.725″
Eccentricity (e)0.28
Details[9]
A
Mass0.69±0.07 M☉
Radius0.58±0.02 R☉
Luminosity0.0789±0.0038 L☉
Surface gravity (log g)4.68±0.07 cgs
Temperature4,024±51 K
Metallicity [Fe/H]−0.05±0.16 dex
Rotation16.3+3.5
−1.3 d
Rotational velocity (v sin i)2.9±1.2 km/s
Age1–7 Gyr
B
Mass0.64±0.07 M☉
Radius0.58±0.03 R☉
Luminosity0.0792±0.0031 L☉
Surface gravity (log g)4.68±0.07 cgs
Temperature4,005±51 K
Metallicity [Fe/H]−0.03±0.16 dex
Rotation16.61±0.04 d
Rotational velocity (v sin i)2.3±1.5 km/s
Age1–7 Gyr
Other designations
GJ 338, ADS 7251, WDS J09144+5241
A: BD+53°1320, HD 79210, HIP 45343
B: BD+53°1321, HD 79211, HIP 120005
Database references
SIMBADThe system
A
B

ADS 7251 is a binary star system 6.33 parsecs (20.66 light years) from the Sun. The components are near-identical red dwarfs separated by 17″ in 2019.

The two stars share a mildly eccentric orbit with a semimajor axis of 16.725″ and a period of 975 years. Their separation has closed from 21.1″ when they were discovered by F. G. W. Struve in 1821 to 16.9″ in 2019. Struve also documented two much fainter stars about 3′ from the two red dwarfs.[10]

ADS 7251 A is 0.06 magnitudes (six percent) brighter than ADS 7251 B. A catalogue of MK spectral classes lists both stars as secondary standards, with ADS 7251 A being class M0V and ADS 7251 B being class K7V, noted as being unusual in the brighter star having a later spectral type.[4] Other publications have described the stars as being both K7V, both M0V, or the primary being K7V and the secondary M0V.[11][9]

  1. ^ a b c d e f g Cite error: The named reference dr3a was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference huang2015 was invoked but never defined (see the help page).
  3. ^ a b c d e f g Cite error: The named reference dr3b was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Kirkpatrick1991 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference 2mass was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference bobylev2006 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference houdebine2019 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference malkov2012 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference ga2020 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference wds was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference skiff was invoked but never defined (see the help page).


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