Y Sagittarii

Y Sagittarii

A light curve for Y Sagittarii, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 18h 21m 22.98643s[2]
Declination −18° 51′ 36.0018″[2]
Apparent magnitude (V) 5.76[3]
Characteristics
Spectral type F8 II[4]
B−V color index 0.67±0.02[3]
Variable type Cepheid variable[4]
Astrometry
Radial velocity (Rv)−1.4±2.3[3] km/s
Proper motion (μ) RA: −3.12[2] mas/yr
Dec.: −7.12[2] mas/yr
Parallax (π)2.13 ± 0.29 mas[5]
Distanceapprox. 1,500 ly
(approx. 470 pc)
Absolute magnitude (MV)−2.06[3]
Details
Surface gravity (log g)1.80[4] cgs
Temperature5,967±26[4] K
Age330[6] Myr
Other designations
57 G. Sgr, Y Sgr, BD−18° 4926, HD 168608, HIP 89968, HR 6863[7]
Database references
SIMBADdata

Y Sagittarii is a variable star in the constellation of Sagittarius. It is a Cepheid variable with an apparent magnitude that ranges around +5.77. The measure of its parallax by Hubble Space Telescope puts Y Sagittarii to 1,293 light-years away from the Solar System.

The brightness ranges in Y Sagittarii's apparent magnitude varies from +5.25 and +6.24 in a period of 5.7736 days. The spectral type of this star is F8II, while the effective temperature is 5370 K. It has a radius 50 times larger than the Sun, while its projected rotational velocity of 16 km / s and it has an estimated mass six times that of the Sun. The star's metal content is similar to Sun, with an index of metallicity [Fe / H] = +0.05. For other metals tested, it shows some overabundance of copper, zinc, yttrium and sodium; the level of the elements is almost double that of the Sun ([Na / H] = +0.27).[8]

There is evidence that Y Sagittarii may be a spectroscopic binary. It has been suggested that the orbital period for the system is on the order of 10,000 to 12,000 days. However, subsequent studies assume eccentricity zero for orbit, and they have failed to find a convincing orbital solution. Instead, it appears to be a distant visual companion.[9]

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  2. ^ a b c d Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  4. ^ a b c d Cite error: The named reference Usenko_et_al_2013 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Benedict_et_al_2017 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference wolframalpha was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference simbad was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference harvard was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Evans_et_al_2020 was invoked but never defined (see the help page).