U Microscopii

Last updated
U Microscopii
Observation data
Epoch J2000       Equinox J2000
Constellation Microscopium
Right ascension 20h 29m 15.77460s [1]
Declination 40° 25 01.3084 [1]
Apparent magnitude  (V)7.0 - 14.4 [2]
Spectral type M5e-M7e [3]
Variable type Mira [2]
Radial velocity (Rv)54.00 [4]  km/s
Proper motion (μ)RA: 13.68 [1]   mas/yr
Dec.: 24.38 [1]   mas/yr
Parallax (π)1.5546 ± 0.1456 [5]   mas
Distance 2,100 ± 200  ly
(640 ± 60  pc)
Luminosity 7,900 [6]   L
Temperature 2,995 [7]   K
Other designations
U  Microscopii, HIP  101063, HD  194814, CD 40°13888
Database references

U Microscopii is a Mira variable star in the constellation Microscopium. It ranges from magnitude 7 to 14.4 over a period of 334 days. [3] The Astronomical Society of Southern Africa in 2003 reported that observations of U Microscopii were very urgently needed as data on its light curve was incomplete. [8]

Related Research Articles

28 Andromedae is a Delta Scuti variable star in the constellation Andromeda. 28 Andromedae is the Flamsteed designation. It also bears the variable star name GN Andromedae. Its apparent magnitude is 5.214, varying by less than 0.1 magnitudes.

21 Cancri is a double star in the northern zodiac constellation of Cancer. It is just visible to the naked eye as a dim, red-hued star with an apparent visual magnitude of 6.08. The star is located around 820 light years away from the Sun, based on parallax. It is moving further from the Earth with a heliocentric radial velocity of 35 km/s.

Y Carinae is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.

V385 Andromedae Star in the constellation Andromeda

V385 Andromedae is a variable star in the constellation Andromeda, about 360 parsecs (1,200 ly) away. It is a red giant over a hundred times larger than the sun. It has an apparent magnitude around 6.4, just about visible to the naked eye in ideal conditions.

R Arae is an Algol-type eclipsing binary in the constellation Ara. Located approximately 298 parsecs (970 ly) distant, it normally shines at magnitude 6.17, but during eclipses can fall as low as magnitude 7.32. It has been suggested by multiple studies that mass transfer is occurring between the two stars of this system, and the period of eclipses seems to be increasing over time. The primary is a blue-white main sequence star of spectral type B5V that is 5 times as massive as the Sun, while the secondary is a yellow-white star of spectral type F1IV that is 1.5 times as massive as the Sun. Stellar material is being stripped off the secondary and accreting on the primary.

PU Aurigae is an irregular variable star located in the constellation Auriga. A red giant, it varies by 0.1 magnitude around magnitude 5.64. Located around 560 light-years distant, it shines with a luminosity approximately 1,523 times that of the Sun and has a surface temperature of 3,482 K.

HD 123657

HD 123657, or BY Boötis, is a variable star of magnitude 4.98–5.33V. This makes it a dim naked eye star. The star is located near the end of the handle of the Big Dipper, but just within the boundaries of the constellation Boötes.

HD 130144 is a semiregular variable star in the northern constellation of Boötes. The variation in luminosity has an amplitude of 0.38 in magnitude with no apparent periodicity. This is an X-ray source, and was possibly the first M-type giant star to have a magnetic field directly detected. It is considered to be a single star, although there is nearby companion at an angular separation of 0.2023″ along a position angle of 82.2°.

1 Camelopardalis

1 Camelopardalis is a double star system in the constellation Camelopardalis. Its combined apparent magnitude is 5.56 and it is approximately 800 parsecs (2,600 ly) away.

17 Persei

17 Persei is a single star in the northern constellation of Perseus, located about 390 light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.53. This object is moving further from the Earth at a heliocentric radial velocity of +13 km/s.

136 Tauri is a white-hued binary star system in the zodiac constellation of Taurus. It has a combined apparent visual magnitude of 4.56, which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 7.71±0.22 mas as seen from Earth's orbit, it is located approximately 420 light years from the Sun. The system is moving nearer with a heliocentric radial velocity of −17.2 km/s, and is expected to make its closest approach in 6.5 million years at a distance of 150 ly (45 pc).

Y Centauri or Y Cen is a semiregular variable star in the constellation of Centaurus.

W Canis Majoris is a carbon star in the constellation Canis Major. A cool star, it has a surface temperature of around 2,900 K and a radius 234 times that of the Sun, with a bolometric absolute magnitude of −4.13 and distance estimated at 443 or 445 parsecs based on bolometric magnitude or radius. The Gaia Data Release 2 parallax of 1.8049±0.1454 milliarcseconds implies a distance of about 555 parsecs.

AH Scorpii

AH Scorpii is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.

AC Herculis

AC Herculis, is an RV Tauri variable and spectroscopic binary star in the constellation of Hercules. It varies in brightness between apparent magnitudes 6.85 and 9.0.

V Antliae is a Mira variable star in the constellation Antlia. It varies in brightness between magnitudes 8.2 and 14.0 with a period of 303 days.

V419 Cephei is an irregular variable star in the constellation of Cepheus with an apparent magnitude that varies between 6.54 and 6.89.

HD 151932

HD 151932, also known as WR 78, is a Wolf-Rayet star located in the constellation Scorpius, close to the galactic plane. Its distance is around 1,300 parsecs away from the Earth. Despite being a blue-colored Wolf-Rayet star, it is extremely reddened by interstellar extinction, so its apparent magnitude is brighter for longer-wavelength passbands. HD 151932 lies about 22′ west of the open cluster NGC 6231, the center of the OB association Scorpius OB1; it is not clear whether it is a part of the association or not. With an apparent magnitude of about 6.5, it is one of the few Wolf-Rayet stars that can be seen with the naked eye.

CH Cygni Variable star in the Cygnus constellation

CH Cygni is a red giant, variable, symbiotic binary in the constellation Cygnus. It is the nearest symbiotic star to Earth, and one of the brightest, making it an ideal candidate for study.

T Leporis Variable star in the constellation Lepus

T Leporis is a variable star in the constellation of Lepus, the Hare. It is located half a degree from ε Leporis in the sky; its distance is approximately 1,100 light years from the Solar System. It has the spectral type M6ev, and is a Mira variable — as is R Leporis, in the same constellation — whose apparent magnitude varies between +7.40 and +14.30 with a period of 368.13 days.


  1. 1 2 3 4 van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics. 474 (2): 653–64. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  3. 1 2 Watson, Christopher (4 January 2010). "U Microscopii". AAVSO Website. American Association of Variable Star Observers . Retrieved 24 March 2015.
  4. Turon, C.; Creze, M.; Egret, D.; Gomez, A.; Grenon, M.; Jahreiß, H.; Requieme, Y.; Argue, A. N.; Bec-Borsenberger, A.; Dommanget, J.; Mennessier, M. O.; Arenou, F.; Chareton, M.; Crifo, F.; Mermilliod, J. C.; Morin, D.; Nicolet, B.; Nys, O.; Prevot, L.; Rousseau, M.; Perryman, M. A. C.; et al. (1993). "Version 2 of the HIPPARCOS Input Catalogue". Bull. Inf. Cent. Donnees Astron. Strasbourg 43. 43: 5. Bibcode:1993BICDS..43....5T.
  5. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  6. Uttenthaler, S.; Lebzelter, T. (2010). "Correlation between technetium and lithium in a sample of oxygen-rich AGB variables". Astronomy and Astrophysics. 510: A62. arXiv: 0911.3507 . Bibcode:2010A&A...510A..62U. doi:10.1051/0004-6361/200912548. S2CID   119231142.
  7. McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv: 1208.2037 . Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. S2CID   118665352.
  8. Cooper, Tim (2003). "Presidential address: Amateur Observations - Successes and Opportunities". Monthly Notes of the Astronomical Society of Southern Africa. 62: 234–40. Bibcode:2003MNSSA..62..234C.