Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Mensa |
Right ascension | 04h 58m 17.93697s [2] |
Declination | −75° 16′ 37.9879″ [2] |
Apparent magnitude (V) | 8.60 - 8.89 [3] |
Characteristics | |
Spectral type | K1 III/IVe [4] |
U−B color index | +0.70 [5] |
B−V color index | +1.04 [5] |
Variable type | FK Com [3] |
Astrometry | |
Radial velocity (Rv) | −8.5±2.5 [6] km/s |
Proper motion (μ) | RA: −4.149 mas/yr [2] Dec.: −3.077 mas/yr [2] |
Parallax (π) | 4.5587 ± 0.0161 mas [2] |
Distance | 715 ± 3 ly (219.4 ± 0.8 pc) |
Absolute magnitude (MV) | +0.81 [7] |
Details | |
Mass | 0.983 [8] M☉ |
Radius | 12.3 [9] R☉ |
Luminosity | 68.5 [10] L☉ |
Surface gravity (log g) | 1.63 [11] cgs |
Temperature | 4,691±128 [12] K |
Metallicity [Fe/H] | −0.59 [11] dex |
Rotational velocity (v sin i) | 45±2 [13] km/s |
Other designations | |
Database references | |
SIMBAD | data |
YY Mensae, also known as HD 32918, is a variable star located in the southern circumpolar constellation Mensa. It has an apparent magnitude that fluctuates between 8.6 and 8.9, [3] which is within the visibility of binoculars. Based on parallax measurements from Gaia DR3, it is estimated to be 715 light years distant. [2] It appears to be approaching the Solar System with a heliocentric radial velocity of −8.5 km/s . [6]
This star was known to have an unusual spectrum since the 1970's, but its variability wasn't observed until the 1980's. Collier (1982) found it to be a FK Comae Berenices variable, a class of rapidly rotating giant stars. [15] After a few additional years of observations, HD 32918 was given the variable star designation YY Mensae. [16] A paper in 1987 observed a long and powerful flare coming from the star. [17] X-ray emissions from YY Mensa have been detected in its corona, which may be a result of its fast rotation. [18]
YY Mensae has a stellar classification of K1 III/IVe, [4] indicating an evolved red giant with the blended luminosity class of a giant star and a subgiant. It is chromospherically active and emission lines are also present in its spectra. It has 98% the mass of the Sun [8] but has expanded to 12.3 times its girth. [9] It radiates 68.5 times the luminosity of the Sun [10] from its photosphere at an effective temperature of 4,691 K , [12] giving it an orange hue. Typical for stars its type, YY Mensae spins rapidly, having a projected rotational velocity of 45 km/s . [13] The star is metal deficient, having an iron abundance only 26% that of the Sun. [11]
RV Caeli, also known as HD 28552, is a solitary, red hued variable star located in the southern constellation Caelum, the chisel. It has an apparent magnitude of 6.4, placing it near the limit for naked eye visibility. The object is located relatively far at a distance of 1,340 light years based on parallax measurements from Gaia DR3, but is rapidly receding with a heliocentric radial velocity of 98 km/s.
HD 160342 is a star in the southern constellation of Ara. HD 160342 is its Henry Draper Catalogue designation. It has an apparent visual magnitude of 6.35 and, based upon parallax measurements, is approximately 960 light-years distant from Earth.
CQ Camelopardalis, abbreviated as CQ Cam, is a solitary variable star in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.19, making it visible to the naked eye under ideal conditions. The object is relatively far at a distance of about 2,000 light years but is drifting closer with a heliocentric radial velocity of −22 km/s. It has a peculiar velocity of 21.8+2.1
−1.9 km/s, making it a runaway star.
HD 27245, also known as HR 1335 or rarely 25 H. Camelopardalis is a solitary red-hued star located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.4, making it faintly visible to the naked eye. Gaia DR3 Parallax measurements place it approximately 607 light years away from it the Solar System and is drifting further away with a heliocentric radial velocity of 25.2 km/s. At its current distance, HD 27245's brightness is diminished by 0.36 magnitudes due to extinction from interstellar dust. It has an absolute magnitude of −0.27.
83 Ursae Majoris is a candidate binary star system in the northern circumpolar constellation of Ursa Major. It is a semiregular variable star, and it has been given the variable star designation IQ Ursae Majoris. It ranges in brightness from apparent visual magnitude 4.69 to 4.75. Percy and Au (1994) identified it as a small amplitude red variable with an irregular behavior, having a characteristic time scale of 20 days. Based upon an annual parallax shift of 5.60 mas, it is located roughly 580 light years from the Sun. The system is moving closer with a heliocentric radial velocity of −18.6 km/s.
HD 90132 is a solitary white hued star located in the southern constellation Antlia. It has an apparent magnitude of 5.33, making it one of the brighter members of this generally faint constellation. The star is relatively close at a distance of 135 light years but is receding with a heliocentric radial velocity of 17 km/s.
HD 86267, also known as HR 3932, is a solitary orange-hued star located in the southern constellation Antlia. It has an apparent magnitude of 5.82, allowing it to be faintly seen with the naked eye. Parallax measurements place it a distance of 514 light years and it is currently receding with a heliocentric radial velocity of 3.7 km/s.
Epsilon Mensae, Latinized to ε Mensae, is a single star in the southern circumpolar constellation Mensa. It has an apparent magnitude of 5.52, making it faintly visible to the naked eye under ideal conditions. The object has a heliocentric radial velocity of 10.5 km/s, meaning it is receding from the Solar System, and is estimated to be 454 light years away.
Iota Mensae is a single star about 880 light years away in the faint constellation Mensa. It has a very slightly variable apparent magnitude of 6.0, making it visible with the naked eye under good skies.
θ Mensae, Latinized to Theta Mensae, is a star located in the southern circumpolar constellation Mensa. It has an apparent magnitude of 5.45, making it faintly visible to the naked eye if viewed under ideal conditions. Based on parallax measurements from Gaia Data Release 3, the object is estimated to be 385 light years distant. The value is horribly constrained, but it appears to be receding with a heliocentric radial velocity of 6 km/s.
HD 27022, also known as HR 1327, is a star located in the northern circumpolar constellation Camelopardalis. The object has also been designated as 20 H. Camelopardalis, but is not commonly used in modern times. It has an apparent magnitude of 5.27, allowing it to be faintly visible to the naked eye. Based on parallax measurements from Gaia DR3, the star has been estimated to be 347 light years away. It appears to be approaching the Solar System, having a heliocentric radial velocity of −19.5 km/s.
Nu Mensae, Latinized from ν Mensae, is a solitary star situated in the southern circumpolar constellation Mensa. It has an apparent magnitude of 5.76, making it faintly visible to the naked eye. The star is relatively close at a distance of 176 light years but is receding with a heliocentric radial velocity of 9.1 km/s.
HD 200044 is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.7, allowing it to be faintly seen with the naked eye. The object is located 598 light years away, but is approaching the Solar System with a heliocentric radial velocity of −15.07 km/s.
HD 58425, also known as HR 2830, is an astrometric binary located in the northern circumpolar constellation Camelopardalis. It is faintly visible to the naked eye as an orang point of light at an apparent magnitude of 5.64. Based on parallax measurements from Gaia DR3, the system is estimated to be 470 light years away from Earth. It appears to be rapidly receding from the Sun, having a heliocentric radial velocity of 58.6 km/s. HD 58425 is listed as 54 Ursae Majoris in Johann Hevelius' catalogue, but this was dropped after the official IAU's official constellation borders were drawn.
CW Octantis, also known as HD 148542, is a solitary, white hued variable star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.03, allowing it to be faintly visible to the naked eye. Parallax measurements from Gaia DR3 place the object at a distance of 629 light years. It appears to be receding from the Solar System with a heliocentric radial velocity of 7.1 km/s.
HD 40091, also known as HR 2082, is a solitary star located in the southern constellation Columba, the dove. It has an apparent magnitude of 5.54, making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 501 light years distant. However, it is rapidly receding with a high heliocentric radial velocity of 114 km/s.
DR Chamaeleontis, also known as HD 93237, is a star located in the southern circumpolar constellation Chamaeleon. The system has an average apparent magnitude of 5.97, allowing it to be faintly visible to the naked eye. DR Cha is located relatively far at a distance of 1,060 light years based on Gaia DR3 parallax measurements, but is receding with a poorly constrained heliocentric radial velocity of 18 km/s.
HR 8526, also known as HD 212168, is the primary of a triple star located in the southern circumpolar constellation Octans. The star and its companion have apparent magnitudes of 6.12 and 9.36 respectively. The system is located relatively close at a distance of 76 light years based on Gaia DR3 parallax measurements, but is receding with a heliocentric radial velocity of 15 km/s.
8 Leonis Minoris is a solitary, red hued star located in the northern constellation Leo Minor. It has an apparent magnitude 5.37, making it faintly visible to the naked eye. Based on parallax measurements from the Gaia satellite, the object is estimated to be 492 light years distant. It is receding with a heliocentric radial velocity of 40 km/s. At its current distance, 8 LMi is diminshed by 0.12 magnitudes due to interstellar dust.
HD 59640 is a solitary white hued star located in the southern circumpolar constellation Volans. It has an apparent magnitude of 6.48, placing it near the limit for naked eye visibility. Gaia DR3 parallax measurements place the object at a distance of 262 light years and it is receding with a heliocentric radial velocity of 18.4 km/s. At its current distance, HD 59640's brightness is diminished by three tenths of a magnitude due to interstellar dust.
{{cite journal}}
: CS1 maint: DOI inactive as of November 2024 (link)Audard, M.; Güdel, M.; Skinner, S. L.; Pallavicini, R.; Drake, S. A.; Mewe, R. (December 2002). "Chandra and XMM-Newton X-Ray Spectroscopy of the Hot Corona of YY Mensae". American Astronomical Society Meeting Abstracts. 201: 33.07. Bibcode:2002AAS...201.3307A.
Strassmeier, K.G. (August 2002). "Doppler images of starspots". Astronomische Nachrichten. 323 (3–4): 309–316. Bibcode:2002AN....323..309S. doi:10.1002/1521-3994(200208)323:3/4<309::AID-ASNA309>3.0.CO;2-U. eISSN 1521-3994. ISSN 0004-6337.
Gondoin, P. (December 1999). "Evolution of X-ray activity and rotation on G-K giants". Astronomy and Astrophysics. 352: 217–227. Bibcode:1999A&A...352..217G. ISSN 0004-6361.
Grewing, M.; Bianchi, L.; Cassatella, A. (August 1986). "HD 32918 : Ultraviolet spectrum and optical behaviour". Astronomy and Astrophysics. 164: 31–39. Bibcode:1986A&A...164...31G. ISSN 0004-6361.