Astronomy:Gliese 570
Coordinates: 
14h 57m 28.00144s, −21° 24′ 55.7131″
 The quaternary star system Gliese 570. The T-type methane brown dwarf Gliese 570D is indicated with an arrow. Credit: 2MASS | |
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 14h 57m 28.00144s[1] |
| Declination | −21° 24′ 55.7131″[1] |
| Apparent magnitude (V) | 5.75 / 8.07 / 10.5 |
| Characteristics | |
| Spectral type | K4V / M1V / M3V / T7V |
| U−B color index | 1.06 /1.22 |
| B−V color index | 1.11 / 1.51 |
| Variable type | None |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +26.75±0.12[2] km/s |
| Proper motion (μ) | RA: 1031.472[2] mas/yr Dec.: -1723.619[2] mas/yr |
| Parallax (π) | 169.8843 ± 0.0653[2] mas |
| Distance | 19.199 ± 0.007 ly (5.886 ± 0.002 pc) |
| Absolute magnitude (MV) | 6.89[3] |
| BC | |
| Radial velocity (Rv) | +25.9[4] km/s |
| Proper motion (μ) | RA: 961.78[1] mas/yr Dec.: -1677.83[1] mas/yr |
| Parallax (π) | 168.77 ± 21.54[1] mas |
| Distance | approx. 19 ly (approx. 5.9 pc) |
| Absolute magnitude (MV) | 9.19[3] / 11.05 |
| D | |
| Proper motion (μ) | RA: 1038.08[5] mas/yr Dec.: -1677.59[5] mas/yr |
| Parallax (π) | 169.30 ± 1.70[6] mas |
| Distance | 19.3 ± 0.2 ly (5.91 ± 0.06 pc) |
| Absolute magnitude (MV) | 11.05[citation needed] |
| Details | |
| Mass | 0.802 ± 0.040[7] / 0.55 / 0.35 / 0.05 M☉ |
| Radius | 0.739 ± 0.019[7] / 0.65 R☉ |
| Luminosity (bolometric) | 0.22[note 1] / 0.04 / ? / 3•10−6[8] L☉ |
| Luminosity (visual, LV) | 0.16 / 0.02 / 0.003 / ? L☉ |
| Temperature | 4597 ± 101[7] / 2700 K |
| Metallicity | [math]\displaystyle{ \begin{smallmatrix}\left[\frac{Fe}{H}\right]\ =\ 0.06\end{smallmatrix} }[/math][7] |
| Rotation | 48.3 days |
| Rotational velocity (v sin i) | 1.50[7] km/s |
| Other designations | |
| A: HR 5568, LAL 27173, HD 131977, BD-20°4125, LHS 387, LTT 5949, GCTP 3375.00, SAO 183040, FK5 1391, LFT 1161, LPM 551, Vys 726, HIP 73184 | |
| BC: HD 131976, HIP 73182, LHS 386, LTT 5948, BD-20°4123, SAO 183039, LFT 1160, LPM 550 | |
| D: 2MASS J14571496-2121477 | |
| Database references | |
| SIMBAD | A |
| BC | |
| D | |
| Exoplanet Archive | data |
| ARICNS | data |
Gliese 570 (or 33 G. Librae) is a quaternary star system approximately 19 light-years away. The primary star is an orange dwarf star (much dimmer and smaller than the Sun). The other secondary stars are themselves a binary system, two red dwarfs that orbit the primary star. A brown dwarf has been confirmed to be orbiting in the system. In 1998, an extrasolar planet was thought to orbit the primary star, but it was discounted in 2000.
Distance and visibility
In the night sky, the Gliese 570 system lies in the southwestern part of Libra. The system is southwest of Alpha Librae and northwest of Sigma Librae. In the early 1990s, the European Hipparcos mission measured the parallax of components B and C, suggesting that the system was at a distance of 24.4 light-years from the Sun. This, however, was a relatively large error as Earth-based parallax and orbit observations suggest that the two stars are actually part of a system with Gliese 570 A, and must actually lie at the same distance.
Star system
The primary star of the system (component A) is an orange dwarf star that may just have over three fourths the mass of the Sun, about 77 percent of its radius, and only 15.6 percent of its visual luminosity. It has a separation of 190 astronomical units from the binary components B and C, moving in an eccentric orbit that takes at least 2130 years to complete.[9] Gliese 570 A is spectral type K4V and emits X-rays.[10] Radial velocities of the primary obtained in the course of an extrasolar planet search at Lick Observatory show a linear trend probably due to the orbital motion of the Gliese 570 BC system around the primary.[11]
A binary system in their own right, components B and C are both rather dim red dwarf stars that have less mass, radius, and luminosity than the Sun. Component B is spectral type M1V, component C is spectral type M3V, and both emit X-rays.[10]
On January 15, 2000, astronomers announced that they had found one of the coolest brown dwarfs then known. Catalogued as Gliese 570 D, it was observed at a wide separation of more than 1,500 astronomical unit from the triple star system.[12] It has an estimated mass of 50 times that of Jupiter.
The status of Gliese 570 D as a brown dwarf was confirmed by Doppler spectroscopy at the Cerro Tololo Interamerican Observatory in Chile . The surface temperature of this substellar object was found to be a relatively cool 500 degrees Celsius, making it cooler and less luminous than any other then-known brown dwarf (including the prototype "T" dwarf), and classifying the object as a T7-8V brown dwarf. No X-rays have been reported from this brown dwarf.
Search for planets
In 1998, an extrasolar planet was announced to orbit the primary star within the Gliese 570 system. The planet, identified as "Gliese 570 Ab", was considered doubtful and the claim was retracted in 2000.[13] No extrasolar planets have been confirmed to exist in this multiple star system thus far.
See also
Notes
- ↑ From L=4πR2σTeff4, where L is the luminosity, R is the radius, Teff is the effective surface temperature and σ is the Stefan–Boltzmann constant.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (November 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
- ↑ 2.0 2.1 2.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 Holmberg, J. et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H.
- ↑ Evans, D. S. (1967). "The Revision of the General Catalogue of Radial Velocities". Determination of Radial Velocities and Their Applications 30: 57. Bibcode: 1967IAUS...30...57E.
- ↑ 5.0 5.1 Weinberger, Alycia J.; Boss, Alan P.; Keiser, Sandra A.; Anglada-Escudé, Guillem; Thompson, Ian B.; Burley, Gregory (2016). "Trigonometric Parallaxes and Proper Motions of 134 Southern Late M, L, and T Dwarfs from the Carnegie Astrometric Planet Search Program". The Astronomical Journal 152 (1): 24. doi:10.3847/0004-6256/152/1/24. Bibcode: 2016AJ....152...24W.
- ↑ Faherty, Jacqueline K.; Burgasser, Adam J.; Walter, Frederick M.; Van Der Bliek, Nicole; Shara, Michael M.; Cruz, Kelle L.; West, Andrew A.; Vrba, Frederick J. et al. (2012). "The Brown Dwarf Kinematics Project (BDKP). III. Parallaxes for 70 Ultracool Dwarfs". The Astrophysical Journal 752 (1): 56. doi:10.1088/0004-637X/752/1/56. Bibcode: 2012ApJ...752...56F.
- ↑ 7.0 7.1 7.2 7.3 7.4 Demory, Brice-Olivier; Ségransan, Damien; Forveille, Thierry; Queloz, Didier; Beuzit, Jean-Luc; Delfosse, Xavier; Di Folco, Emmanuel; Kervella, Pierre et al. (October 2009). "Mass-radius relation of low and very low-mass stars revisited with the VLTI". Astronomy and Astrophysics 505 (1): 205–215. doi:10.1051/0004-6361/200911976. Bibcode: 2009A&A...505..205D.
- ↑ Saumon, Didier; Marley, M.; Cushing, Michael C.; Leggett, S.; Roellig, T.; Lodders, K.; Freeman, R. (August 2006), "Ammonia as a Tracer of Chemical Equilibrium in the T7.5 Dwarf Gliese 570D", The Astrophysical Journal 647 (1): 552–557, doi:10.1086/505419, Bibcode: 2006ApJ...647..552S
- ↑ "Sixth Catalog of Orbits of Visual Binary Stars". http://ad.usno.navy.mil/wds/orb6.html.
- ↑ 10.0 10.1 Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. doi:10.1086/176149. Bibcode: 1995ApJ...450..392S.
- ↑ Howard, Andrew W.; Fulton, Benjamin J. (2016). "Limits on Planetary Companions from Doppler Surveys of Nearby Stars". Publications of the Astronomical Society of the Pacific 128 (969): 114401. doi:10.1088/1538-3873/128/969/114401. Bibcode: 2016PASP..128k4401H.
- ↑ Burgasser; Kirkpatrick, J. Davy; Cutri, Roc M.; McCallon, Howard; Kopan, Gene; Gizis, John E.; Liebert, James; Reid, I. Neill et al. (2000). "Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B". The Astrophysical Journal 531 (1): L57–L60. doi:10.1086/312522. PMID 10673414. Bibcode: 2000ApJ...531L..57B.
- ↑ Kurster (2000). "The planet search program at the ESO Coud'e Echelle spectrometer I. Data modeling technique and radial velocity precision tests". Astronomy and Astrophysics 362: 585–594. Bibcode: 2000A&A...362..585E. http://aa.springer.de/papers/0362002/2300585/small.htm. Retrieved 2007-08-19.
External links
- "Gliese 570 / HR 5568 ABC". SolStation. http://www.solstation.com/stars/gl570abc.htm.
- Bridges, Andrew (2000-01-17). "Astronomers Unveil Hot Photo of Cool Star". SPACE.com. http://www.space.com/scienceastronomy/astronomy/brown_dwarf_000117.html.
 |  |
