Astronomy:34 Boötis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Boötes[1] |
| Right ascension | 14h 43m 25.36304s[2] |
| Declination | +26° 31′ 40.2663″[2] |
| Apparent magnitude (V) | 4.49 - 5.40[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | M3− III[5] |
| B−V color index | 1.672±0.006[1] |
| Variable type | Semi-regular[3] |
| Astrometry | |
| Radial velocity (Rv) | +5.60±0.49[1] km/s |
| Proper motion (μ) | RA: −13.57[2] mas/yr Dec.: −16.08[2] mas/yr |
| Parallax (π) | 4.63 ± 0.28[2] mas |
| Distance | 700 ± 40 ly (220 ± 10 pc) |
| Absolute magnitude (MV) | −1.86[1] |
| Details[6] | |
| Mass | 2.20±0.23 M☉ |
| Radius | 129.36+8.42 −7.49 R☉ |
| Luminosity | 2,802±367 L☉ |
| Surface gravity (log g) | 1.24 cgs |
| Temperature | 3,691±50 K |
| Age | 1.05±0.27 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
34 Boötis, also named Alrumh,[8] is a single[9] variable star[3] in the northern constellation Boötes, located around 700 light years away from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction of 0.49±0.02 due to interstellar dust.[6] It has the variable star designation W Boötis; 34 Boötis is the Flamsteed designation. This object is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of around five. It is moving away from the Earth with a heliocentric radial velocity of +5.6 km/s.[1]
This is an aging red giant star with a stellar classification of M3− III,[5] which indicates it has exhausted the supply of hydrogen at its core and evolved off the main sequence branch. It is classified as a semiregular variable with a brightness that varies from magnitude +4.49 down to +5.4 with a period of 25 days,[3] with some evidence of longer term variation and mode switching.[10] The star is around a billion years old with 2.2 times the mass of the Sun and has expanded to 129 times the size of the Sun. It is radiating 2,802 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,691 K.[6]
The parallax calculated in the new Hipparcos reduction is 4.63±0.28 mas,[2] and in Gaia Data Release 2 the parallax is given as 6.3168±0.2900 max.[11] Each has a margin of error of about 5%, but they differ from each other by far more than 5%.
Al-Rumḥ (الرُّمْح), the Lance, is an Arabic asterism in the area of ε Boötis (Izar), η Boötis (Muphrid), σ Boötis (Genghe), and υ Boötis. 34 Boötis is a star in this area near the otherwise-named ε Boötis. The IAU Working Group on Star Names approved the name Alrumh for this star on 15 April 2026.[8]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 3.0 3.1 3.2 3.3 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal 104: 275. doi:10.1086/116239. Bibcode: 1992AJ....104..275E.
- ↑ 5.0 5.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 6.0 6.1 6.2 Baines, E. et al. (2017), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal 155 (1): 30, doi:10.3847/1538-3881/aa9d8b, Bibcode: 2018AJ....155...30B.
- ↑ "34 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=34+Boo.
- ↑ 8.0 8.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 10.0 10.1 Percy, John R. et al. (April 1997), "Sorting Out W Bootis and Its Comparison Stars", Information Bulletin on Variable Stars 4467: 1, Bibcode: 1997IBVS.4467....1P.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
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