Delta Microscopii

Delta Microscopii
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Microscopium
Right ascension 20h 06m 01.14597s[1]
Declination −30° 07′ 30.4290″[1]
Apparent magnitude (V) 5.68[2]
Characteristics
Spectral type K0/1 III[3]
B−V color index +1.03[2]
Astrometry
Proper motion (μ) RA: +33.46[1] mas/yr
Dec.: −67.91[1] mas/yr
Parallax (π)10.82 ± 0.64 mas[1]
Distance300 ± 20 ly
(92 ± 5 pc)
Absolute magnitude (MV)+0.87[4]
Orbit[5]
Period (P)1,599.3±8.15 d
Eccentricity (e)0.2
Periastron epoch (T)2453878.5 ± 3.59 JD
Argument of periastron (ω)
(secondary)		194.4±2.40°
Semi-amplitude (K1)
(primary)		5,581.3±5.42 km/s
Details[6]
δ Mic A
Mass1.96 M☉
Radius10.87 R☉
Luminosity57 L☉
Surface gravity (log g)2.45 cgs
Temperature4,805 K
Metallicity [Fe/H]0.03±0.11 dex
Rotational velocity (v sin i)2.12 km/s
Other designations
δ Mic, CD−39° 14089, FK5 3683, HD 200718, HIP 104148, HR 8070, SAO 212709[7]
Database references
SIMBADdata

δ Microscopii, Latinised as Delta Microscopii, is a faint, orange hued binary star system in the constellation Microscopium, marking the eyepiece end of the "microscope".[8] It is just visible to the naked eye with an apparent visual magnitude of +5.68.[2] Based upon an annual parallax shift of 10.82 mas as seen from the Earth,[1] it is roughly 300 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.142 due to interstellar dust.[6]

This is a single-lined spectroscopic binary with an orbital period of 4.4 years and an eccentricity of 0.2.[5] The visible component is an evolved K-type giant star with a stellar classification of K0/1 III.[3] It is currently on the horizontal branch and thus is generating energy through helium fusion at its core.[6] Delta Microscopii has nearly twice the mass of the Sun and has expanded to 11 times the Sun's radius. The star is radiating 57 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,805 K.[6]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Lake1965 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference houk1979 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference bluhm2016 was invoked but never defined (see the help page).
  6. ^ a b c d Cite error: The named reference Jones2011 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 Ridpath was invoked but never defined (see the help page).