AO Mensae

AO Mensae is a single^[8] variable star in the southern circumpolar constellation of Mensa. It is too faint to be viewed with the naked eye, having an apparent visual magnitude that ranges from 9.96 down to 10.18.^[3] The star is 128 light years distant from the Sun based on parallax,^[2] and is drifting further away with a radial velocity of +16 km/s.^[6] It is a member of the Beta Pictoris moving group, a loose association of young stars moving through the galaxy.^[8]

AO Mensae

A visual band light curve for AO Mensae, adapted from Kiraga (2012)[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Mensa
Right ascension	06h 18m 28.20850s[2]
Declination	−72° 02′ 41.4464″[2]
Apparent magnitude (V)	9.96 to 10.18[3]
Characteristics
Spectral type	K4Ve[4]
B−V color index	+1.13[5]
Variable type	BY Dra[3]
Astrometry
Radial velocity (Rv)	+16.2±1.0[6] km/s
Proper motion (μ)	RA: −7.908[2] mas/yr Dec.: +74.295[2] mas/yr
Parallax (π)	25.4695 ± 0.0254 mas[2]
Distance	128.1 ± 0.1 ly (39.26 ± 0.04 pc)
Absolute magnitude (MV)	7.02[7]
Details[6]
Mass	0.69 M☉
Radius	0.91±0.29[8] R☉
Luminosity	0.26 L☉
Surface gravity (log g)	4.38 cgs
Temperature	4,384±59 K
Metallicity [Fe/H]	0.24 dex
Rotation	2.673 d
Rotational velocity (v sin i)	16.4 km/s
Age	23±3[9] Myr
Other designations
AO Men, CD−71°333, CPD−71° 427, HD 45081, HIP 29964[10]
Database references
SIMBAD	data

This is an orange-hued K-type main-sequence star with a stellar classification of K4Ve,^[4] where the 'e' suffix indicates emission features in the spectrum. It is young star and an X-ray source, one of the brightest such X-ray emitters in the solar neighborhood,^[11] and is categorized as a BY Draconis variable, although there is some uncertainty in this assignment.^[3] It is spinning with a period of 2.7^[6] days and is about 23^[9] million years old. The star has 69%^[6] of the mass of the Sun and 91%^[8] of the Sun's radius. It is radiating 26% of the luminosity of the Sun on average, at an effective temperature of 4,384 K.

References

1. Kiraga, M. (March 2012). "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey". Acta Astronomica. 62 (1): 67–95. arXiv:1204.3825. Bibcode:2012AcA....62...67K. Retrieved 26 January 2022.
2. 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.
3. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
4. Torres, C. A. O.; et al. (2006). "Search for associations containing young stars (SACY)". Astronomy & Astrophysics. 460 (3): 695. arXiv:astro-ph/0609258. Bibcode:2006A&A...460..695T. doi:10.1051/0004-6361:20065602. S2CID 16080025.
5. Messina, S.; et al. (2010). "RACE-OC project: Rotation and variability of young stellar associations within 100 pc". Astronomy and Astrophysics. 520: A15. arXiv:1004.1959. Bibcode:2010A&A...520A..15M. doi:10.1051/0004-6361/200913644. S2CID 118569400.
6. Luck, R. Earle (March 2018). "Abundances in the Local Region. III. Southern F, G, and K Dwarfs". The Astronomical Journal. 155 (3): 31. Bibcode:2018AJ....155..111L. doi:10.3847/1538-3881/aaa9b5. S2CID 125765376. 111.
7. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
8. Messina, S.; et al. (April 2017). "The β Pictoris association: Catalog of photometric rotational periods of low-mass members and candidate members". Astronomy & Astrophysics. 600: 72. arXiv:1612.04591. Bibcode:2017A&A...600A..83M. doi:10.1051/0004-6361/201629152. S2CID 53952768. A83.
9. Meshkat, Tiffany; et al. (December 2017). "A Direct Imaging Survey of Spitzer-detected Debris Disks: Occurrence of Giant Planets in Dusty Systems". The Astronomical Journal. 154 (6): 21. arXiv:1710.04185. Bibcode:2017AJ....154..245M. doi:10.3847/1538-3881/aa8e9a. S2CID 42042014. 245.
10. "AO Men". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-10.
11. Makarov, Valeri V. (October 2003). "The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun". The Astronomical Journal. 126 (4): 1996–2008. Bibcode:2003AJ....126.1996M. doi:10.1086/378164.