Pi1 Ursae Majoris
Location of π¹ Ursae Majoris (circled) | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ursa Major |
Right ascension | 08h 39m 11.70440s[1] |
Declination | +65° 01′ 15.2667″[1] |
Apparent magnitude (V) | 5.63 |
Characteristics | |
Spectral type | G1.5Vb[2] |
U−B color index | +0.07[3] |
B−V color index | +0.62[3] |
Variable type | BY Draconis |
Astrometry | |
Radial velocity (Rv) | –13.88 ± 0.47[4] km/s |
Proper motion (μ) | RA: -27.44 ± 0.31[1] mas/yr Dec.: +88.13 ± 0.26[1] mas/yr |
Parallax (π) | 69.66 ± 0.37[1] mas |
Distance | 46.8 ± 0.2 ly (14.36 ± 0.08 pc) |
Absolute magnitude (MV) | 4.86 |
Details | |
Mass | 0.90[5] M☉ |
Luminosity | 0.97[6] L☉ |
Surface gravity (log g) | 4.48[7] cgs |
Temperature | 5,884 ± 6.8[8] K |
Metallicity [Fe/H] | –0.04[7] dex |
Rotation | 5 days[9] |
Rotational velocity (v sin i) | 14.27[4] km/s |
Age | 200[10] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Pi1 Ursae Majoris (Pi1 UMa, π¹ Ursae Majoris, π¹ UMa) is a yellow G-type main sequence dwarf with a mean apparent magnitude of +5.63. It is approximately 46.8 light years from Earth,[1] and is a relatively young star with an age of about 200 million years.[10] It is classified as a BY Draconis type variable star and its brightness varies by 0.08 magnitudes. In 1986, it became the first solar-type star to have the emission from an X-ray flare observed.[11] Based upon its space velocity components, this star is a member of the Ursa Major moving group of stars that share a common motion through space.[6][9]
An excess of infrared radiation has been detected from this system, which suggests the presence of a debris disk. The best fit to the data indicates that there is a ring of fine debris out to a radius of about 0.4 AU, consisting of 0.25 μm grains of amorphous silicates or crystalline forsterite. There may also be a wider ring of larger (10 μm) grains out to a distance of 16 AU.[12]
References
- 1 2 3 4 5 6 van Leeuwen, Floor (2007). Hipparcos, the new Reduction of the Raw data. Astrophysics and Space Science Library. 350. Bibcode:2007A&A...474..653V. ISBN 978-1-4020-6341-1. Note: see VizieR catalogue I/311.
- ↑ Montes, D.; et al. (November 2001), "Late-type members of young stellar kinematic groups - I. Single stars", Monthly Notices of the Royal Astronomical Society, 328 (1): 45–63, arXiv:astro-ph/0106537, Bibcode:2001MNRAS.328...45M, doi:10.1046/j.1365-8711.2001.04781.x
- 1 2 Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J
- 1 2 White, Russel J.; Gabor, Jared M.; Hillenbrand, Lynne A. (June 2007), "High-Dispersion Optical Spectra of Nearby Stars Younger Than the Sun", The Astronomical Journal, 133 (6): 2524–2536, arXiv:0706.0542, Bibcode:2007AJ....133.2524W, doi:10.1086/514336
- ↑ Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 2, arXiv:1007.0425, Bibcode:2011ApJS..192....2S, doi:10.1088/0067-0049/192/1/2
- 1 2 Gaidos, E. J.; Henry, G. W.; Henry, S. M. (August 2000), "Spectroscopy and Photometry of Nearby Young Solar Analogs", The Astronomical Journal, 120 (2): 1006–1013, Bibcode:2000AJ....120.1006G, doi:10.1086/301488
- 1 2 Cenarro, A. J.; et al. (January 2007), "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters", Monthly Notices of the Royal Astronomical Society, 374 (2): 664–690, arXiv:astro-ph/0611618, Bibcode:2007MNRAS.374..664C, doi:10.1111/j.1365-2966.2006.11196.x
- ↑ Kovtyukh, V. V.; et al. (2003), "High precision effective temperatures for 181 F-K dwarfs from line-depth ratios", Astronomy and Astrophysics, 411 (3): 559–564, arXiv:astro-ph/0308429, Bibcode:2003A&A...411..559K, doi:10.1051/0004-6361:20031378
- 1 2 Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, arXiv:1007.1132, Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948
- 1 2 Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785
- ↑ Landini, M.; et al. (March 1986), "EXOSAT detection of an X-ray flare from the solar type star Pi-prime UMa", Astronomy and Astrophysics, 157 (2): 217–222, Bibcode:1986A&A...157..217L
- ↑ Beichman, C. A.; et al. (2006), "IRS Spectra of Solar-Type Stars: A Search for Asteroid Belt Analogs", The Astrophysical Journal, 639 (2): 1166–1176, arXiv:astro-ph/0601467, Bibcode:2006ApJ...639.1166B, doi:10.1086/499424