R Muscae

A light curve for R Muscae, plotted from TESS data [1]
Observation data Epoch J2000       Equinox J2000
Constellation	Musca
Right ascension	12h 42m 05.02561s [2]
Declination	−69° 24′ 27.1966″ [2]
Apparent magnitude (V)	5.93 - 6.73 [3]
Characteristics
Spectral type	F7 Ib [4] - G2 [3]
B−V color index	0.750±0.020 [5]
Variable type	δ Cep [3]
Astrometry
Radial velocity (Rv)	+3.8±2.9 [6] km/s
Proper motion (μ)	RA: −4.180 [2]  mas/ yr Dec.: −2.127 [2]  mas/ yr
Parallax (π)	1.0002 ± 0.0291  mas [2]
Distance	3,260 ± 90  ly (1,000 ± 30  pc)
Absolute magnitude (MV)	-3.62 [7]
Details
Radius	65 [2]  R☉
Luminosity	2,541 [2]  L☉
Surface gravity (log g)	2.0±0.1 [8]  cgs
Temperature	5,985±54 [7]  K
Metallicity [Fe/H]	+0.10±0.05 [8]  dex
Other designations
R Mus, CD−68°1119, HD 110311, HIP 61981, HR 4820, SAO 251996 [9]
Database references
SIMBAD	data

R Muscae is a yellow-white hued variable star in the southern constellation of Musca. It has a nominal apparent visual magnitude of 6.31, ^[5] which is near the lower limit of visibility to the naked eye. The distance to this star, as determined from its annual parallax shift of 1.00  mas, ^[2] is around 3,260  light years.

This is an F-type supergiant star with a baseline stellar classification of F7 Ib. ^[4] It is a Classical Cepheid variable ranging from apparent magnitude 5.93 to 6.73 ^[10] over 7.51 days, ^[7] while varying between spectral types F7 Ib and G2. ^[10] The star was suspected of having a detectable companion, ^[11] but this finding was later disputed. ^[12] Gaia and HST observations have shown that there is a companion, a 15th-magnitude star 7 ″ away. ^{[13] [14]} There is an X-ray source with a luminosity of 6.3×10²⁹ erg s⁻¹ located at an angular separation of 1.9 ″ from R Muscae. ^[15]

References