91 Aquarii
| |
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Aquarius |
Right ascension | 23h 15m 53.49482s[1] |
Declination | –9° 05′ 15.8546″[1] |
Apparent magnitude (V) | +4.248[2] |
Characteristics | |
Spectral type | K0 III[3] |
U−B color index | +1.035[2] |
B−V color index | +1.104[2] |
R−I color index | 0.56[4] |
Astrometry | |
Radial velocity (Rv) | ±0.74 −25.49[5] km/s |
Proper motion (μ) | RA: +368.78[1] mas/yr Dec.: –17.16[1] mas/yr |
Parallax (π) | 21.77 ± 0.29[1] mas |
Distance | 150 ± 2 ly (45.9 ± 0.6 pc) |
Details | |
Mass | ±0.35 1.74[6] M☉ |
Radius | ±0.45 10.16[6] R☉ |
Luminosity | 49[5] L☉ |
Surface gravity (log g) | 2.6[5] cgs |
Temperature | 4603[5] K |
Metallicity [Fe/H] | –0.14[5] dex |
Rotational velocity (v sin i) | 2.9[5] km/s |
Age | +0.16 −0.34 1.25[7] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Data sources: | |
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.) | |
Database references | |
SIMBAD | data |
91 Aquarii is the Flamsteed designation for a triple star[8] system in the equatorial constellation of Aquarius. It also bears the Bayer designation Psi1 Aquarii (ψ1 Aqr, ψ1 Aquarii). It is visible to the naked eye with an apparent visual magnitude of +4.248.[2] Parallax measurements yield an estimated distance of around 150 light-years (46 parsecs) from Earth.[1] An extrasolar planet is known to orbit the main star.
Stellar system
91 Aquarii is a triple star system.[8] The primary component, 91 Aqr A, is a giant star with a stellar classification of K0 III.[3] This is an evolved star with 174% of the Sun's mass that has expanded to over 10 times the size of the Sun.[6] It is radiating 49[5] times the Sun's luminosity from its outer envelope at an effective temperature of 4,603 K.[5] This gives it the orange-hued glow of a K-type star.[9]
The primary shares a common proper motion with two others stars, 91 Aqr B and C, suggesting that they are physically connected.[10] The latter pair form a binary system located at an angular separation of 52 arcseconds from the primary.[3] They are 10th magnitude stars separated by 0.3 arcseconds from each other.
Component | Apparent magnitude (V) |
Spectral type |
---|---|---|
A | 4.22 | K0 III |
B | 9.62 | K3 V |
C | 10.10 |
Because it lies near the same line of sight, the binary star system CCDM J23159-0905DE was listed to belong to the 91 Aquarii system according to the CCDM catalogue. However, it is listed as physically unconnected in the WDS catalogue and the pair have a different proper motion than 91 Aquarii.[10] CCDM J23159-0905DE has two components, the 13th magnitude CCDM J23159-0905D 80.4 arcseconds from 91 Aquarii, and the 14th magnitude CCDM J23159-0905E 19.7 arcseconds from 91 Aquarii.
Planetary system
In 2003, the discovery of an extrasolar planet orbiting 91 Aquarii A was announced. Despite controversy, the exoplanet was confirmed again on Jan 03, 2011 by the Conference " Planetary Systems Beyond the Main Sequence", Bamberg 2010 (Quirrenbach et al.).
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥ 2.9[11] MJ | ≥ 0.3[11] | 182[12] | 0 | — | — |
See also
References
- 1 2 3 4 5 6 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
- 1 2 3 4 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
- 1 2 3 Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram, 4, Bibcode:1962MtSOM...4....1B.
- ↑ VizieR Detailed Page for HR 8841, retrieved 2009-11-28.
- 1 2 3 4 5 6 7 8 Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
- 1 2 3 Ghezzi, L.; et al. (December 2010), "Metallicities of Planet-hosting Stars: A Sample of Giants and Subgiants", The Astrophysical Journal, 725 (1): 721–733, arXiv:1008.3539, Bibcode:2010ApJ...725..721G, doi:10.1088/0004-637X/725/1/721.
- ↑ Chanamé, Julio; Ramírez, Iván (February 2012), "Toward Precise Ages for Single Stars in the Field. Gyrochronology Constraints at Several Gyr Using Wide Binaries. I. Ages for Initial Sample", The Astrophysical Journal, 746 (1): 102, arXiv:1109.0013, Bibcode:2012ApJ...746..102C, doi:10.1088/0004-637X/746/1/102
- 1 2 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16.
- 1 2 Roell, T.; Neuhäuser, R.; Seifahrt, A.; Mugrauer, M. (June 2012), "Extrasolar planets in stellar multiple systems", Astronomy & Astrophysics, 542: A92, arXiv:1204.4833, Bibcode:2012A&A...542A..92R, doi:10.1051/0004-6361/201118051
- 1 2 Raghavan, Deepak; et al. (July 2006), "Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems", The Astrophysical Journal, 646 (1): 523–542, arXiv:astro-ph/0603836, Bibcode:2006ApJ...646..523R, doi:10.1086/504823.
- ↑ Mitchell, D. S.; S. Frink; A. Quirrenbach; D. A. Fischer; G. W. Marcy; R. P. Butler (2004-01-05). "Four Substellar Companions Found Around K Giant Stars". Bulletin of the American Astronomical Society, 35#5; AAS 203rd Meeting; Session 17 Extra Solar Planets. Retrieved 2009-11-28.
External links
- "Simbad query result for GJ 893.2 A". Retrieved 2009-11-28.
- "Simbad query result for GJ 893.2 B". Retrieved 2009-11-28.
- SIMBAD: HD 219449 -- High proper-motion Star
- Extrasolar Planets Encyclopaedia: 91 Aqr
- Orbit simulation
- Image Psi Aquarii
- sky-map.org/
- planetquest.jpl.nasa.gov
Coordinates: 23h 15m 53.5s, −09° 05′ 16″