House likely to pass Senate's vision for NASA

[sandi66]

House likely to pass Senate's vision for NASA
By Gautham Nagesh - 09/28/10 02:53 PM ET

The House appears poised to pass the Senate's $19 billion reauthorization of NASA on Wednesday, preserving the space shuttle program through next year but giving the White House most of their desired cuts to the human spaceflight program.

If the House approves the bill, which passed the Senate unanimously last month, it would mean an end to most of the Constellation program and increasing reliance on Russia and the commercial space industry to ferry American astronauts to the International Space Station.


The move would also put a temporary stop to a year of wrangling over the agency's future. Lawmakers, particularly those from Florida and Texas with numerous NASA jobs in their districts, have strongly resisted the administration's attempts to privatize human spaceflight. The authorization would lay out a three-year vision for NASA but would still require appropriators to fund the bill's priorities at a later date.


House Science Committee chairman Bart Gordon, (D-Tenn.) said he will support what he considers a flawed Senate bill because there isn't enough time to reach a deal before the start of the new fiscal year on October 1. Gordon offered a compromise of his own last week but that effort stalled after meeting opposition in the upper chamber.


The bill includes $1.6 billion to boost the commercial space industry, $400 million more than in Gordon's bill but still less than half the amount requested by the White House. But the Commercial Spaceflight Foundation said passing the Senate bill would be vastly preferable to continued uncertainy, which may result in layoffs.

The Senate bill also deviates from President Obama's plans by continuing the space shuttle program for one final flight next year. The bill would also preserve aspects of the Constellation program including the Orion crew capsule and a heavy-lift rocket designed to travel to Mars, both of which are opposed by the administration. The projects survived partly due to the vocal efforts of Sens. Kay Bailey Hutchinson (R-Texas) and Bill Nelson (D-Fla.).


A Senate aide the bill would also substantially invest in advanced exploration technologies and robotics. The Senate bill moves up the timetable for the development of a long-range space vehicle in response to lawmakers' concerns about relying on Russia for human spaceflight.

Source:
thehill.com/blogs/hillicon-valley/technology/121399-house-likely-to-pass-senates-vision-for-nasa
The contents of this site are © 2010 Capitol Hill Publishing Corp., a subsidiary of News Communications, Inc.
Comments (4)Senate bill not as good as President Obama's original proposal but a definite step in the right direction. Once the Republican & Democrat porkers get past the election they'll appreciate what it does for the American business community and both will be calling it there own by next election cycle.

sftommy
BY sftommy on 09/28/2010 at 15:56
Human spaceflight is the main reason NASA exists. Gutting it and setting our space program back years is shameful, especially because this proposal produces no budget savings at all.
There's no need to wait decades for advanced propulsion. Plain old chemical rockets, in a heavy-lift booster, just as called for in the Vision for Space Exploration and the Mars Direct Plan, will do just great.
BY Carney on 09/28/2010 at 16:43
Carney, gutting government HSF is not the same as gutting all HSF. The gap between shuttle and the next crew launch system is the product of decades of political neglect and Griffin's bold brinksmanship — and not a distinction between the commercial and government paths. Commercializati on may not save money this year, but will for generations to come. Government monopoly on HSF is too expensive, because there is no incentive for driving costs down.

Chemical rockets at a colossal scale might work, but that still implies depots and other advanced on-orbit facilities that don't exist. Even so, the risks of radiation and normal medical emergencies for astronauts during a placid multi-year transit to Mars are not trivial. Have you accepted the possibility of losing astronaut lives during each trip? I am sure the country hasn't.
BY Papa on 09/28/2010 at 19:13
The possibilities for new and advanced technology propulsion systems, e.g. ion, fusion and solar will cut exposure time of astronauts to deep space radiation. The Senate measure directs investment in such technologies. Commercial access to low earth orbit and the moon will enable the space agency to look to deep space and advance new propulsion technologies and gain the means to mitigate against the health consequences of long-term deep space flights. Suspend the rules and 'let's go!'
BY JackKennedy on 09/28/2010 at 20:00

thehill.com/blogs/hillicon-valley/technology/121399-house-likely-to-pass-senates-vision-for-nasa

[sandi66]

Alien World Tour: The Exoplanets Around Star Gliese 581

Wednesday, September 30, 2010 - 1 hr 12 mins ago

The announcement Wednesday (Sept. 29) of two newfound alien planets circling the star Gliese 581 adds to the nearby solar system's intrigue, further cementing its status as a top candidate to harbor extraterrestrial life.

One of the two newly discovered planets, known as Gliese 581g, is a small, Earth-like world that likely lies within its star's habitable zone — the just-right range of distances that allow liquid water to exist. [Artist's conception of Gliese 581g.]

Astronomers have now detected six planets orbiting Gliese 581, the most known to circle any star beyond our own sun. Here's a brief tour of the star and its planets, from the inside out:

Gliese 581: the mother star

Gliese 581 is a red dwarf located 20.5 light-years from Earth, in the constellation Libra. Like other red dwarfs, it's smaller and much dimmer than our sun. Scientists believe Gliese 581 is old — at least a few billion years — and relatively stable. Both are qualities conducive to the evolution of life, scientists have said.

Nearest planet

The nearest planet to the star is Gliese 581e, a rocky world nearly twice as massive as Earth.

Gliese 581e is extremely close to its parent star — it completes an orbit every 3.15 days — so it's likely far too hot for life to have any chance of taking root.

Gliese 581e is about 0.033 astronomical units from its parent star. One astronomical unit, or AU, is the average distance between the Earth and sun, about 93 million miles (150 million km).

Astronomers announced this planet's discovery in April 2009, and it's in the running for the lightest known extrasolar planet. So far, the only potential alien planet less massive than Gliese 581e is a world about 1.4 times the mass of Earth, but its existence — around a more distant star — has not yet been confirmed.

Next up: Gliese 581b

Traveling outward, the next planet is Gliese 581b, a Neptune-size alien world that's about 16 times as massive as Earth. This planet is still very close to the star, completing an orbit in 5.4 days. Astronomers first discovered this planet in December 2005, according to an extrasolar planet database maintained by NASA's Jet Propulsion Laboratory. Its average distance from the Gliese 581 star is about 0.041 AU.

Rocky world in third

Gliese 581c comes next. This is a rocky, smallish planet — about five Earth masses — that makes a full trip around the red dwarf every 15 days.

Astronomers once thought Gliese 581c might be in the habitable zone, but later observations suggested the planet is likely too hot to support liquid water or life. The planet is about 0.073 AU from its parent star.

Meet Gliese 581g

Unlike Gliese 581c, the newfound planet Gliese 581g looks much more hospitable. It is orbiting within the habitable zone of its parent star.

Gliese 581g is three to four times as massive as Earth, is most likely rocky, and may have an atmosphere, scientists say. It orbits about 0.146 AU from the central star.

Liquid water could exist on some part of the planet's surface, which seems to have an average temperature between minus 24 and minus 10 degrees Fahrenheit (minus 31 to minus 12 degrees Celsius). Gliese 581g completes an orbit every 37 days or so.

Fifth planet is a super-Earth

The next planet in line is a so-called super-Earth, Gliese 581d, which is seven or eight times as massive as Earth and completes an orbit every 67 days.

Though at first glance this planet appeared to be beyond the star's habitable zone, astronomers think it might just squeak in — computer models suggest a greenhouse effect could be warming its surface. It was discovered in April 2007 and orbits about 0.22 AU from its parent star.

Sixth planet on the outskirts

The outermost planet in the Gliese 581 system (that astronomers know about, anyway) is the newly discovered Gliese 581f, announced today.

This planet is much farther away than the other five planets, zipping through space far outside the habitable zone, but it is still closer to its parent star than the Earth is to our sun. The planet is about 0.76 AU from its parent star.

Like all of the planets in the Gliese 581 system — and in our own solar system — Gliese 581f's orbit is nearly circular, scientists said.

news.yahoo.com/s/space/20100930/sc_space/alienworldtourtheexoplanetsaroundstargliese581

[sandi66]

Gliese 581

From Wikipedia

Gliese 581 (pronounced /ˈɡliːzə/) is a red dwarf star with spectral type M3V, located 20.3 light years away from Earth in the constellation Libra. Its estimated mass is about a third of that of the Sun, and it is the 87th[9] closest known star system to the Sun. Observations suggest that the star has at least six planets: Gliese 581 e, b, c, g, d and f. Significantly, planet g is thought to be close to the middle of the star's habitable zone,[10][11] although it is expected to be tidally locked.[11]

The star system first gained attention after Gliese 581 c, the first low mass extrasolar planet found to be near its star's habitable zone, was discovered in April 2007. It has since been shown that under known terrestrial planet climate models, Gliese 581 c is likely to have a runaway greenhouse effect, somewhat like Venus, and hence is probably not habitable. A subsequently discovered planet Gliese 581 d, somewhat like Mars, may be just inside or just outside the outer boundary of the habitable zone (depending in part on the greenhouse properties of its atmosphere).[11] The discovery of exoplanet Gliese 581 e,[12] at that time the closest-known in mass to Earth, was announced in April 2009. Excitement has again spiked with the discovery of Gliese 581 g, believed to be the most "Earth-like" planet discovered to date, in September 2010.[13]




Contents [hide]
1 Star
2 Planetary system
3 Message from Earth
4 See also
5 Notes
6 References
7 External links


[edit] Star
The name Gliese 581 refers to the catalog number from the 1957 survey Gliese Catalogue of Nearby Stars of 965 stars located within 20 parsecs of the Earth. Other names of this star include BD-07° 4003 (BD catalogue, first known publication) and HO Librae (variable star designation). It does not have an individual name such as Sirius or Procyon.[1][8] The star is a red dwarf with spectral type M3V, located 20.3 light years away from Earth. It is located about two degrees north of Beta Librae, the brightest star in the constellation Libra. Its mass is estimated to be approximately a third that of the Sun, and it is the 87th closest known star system to the Sun.[9]


Size of the Sun (left) and Gliese 581 (right).An M-class dwarf star such as Gliese 581 has a much lower mass than the Sun, causing the core region of the star to burn hydrogen at a significantly lower rate. From the apparent magnitude and distance, we can estimate an effective temperature of 3200 kelvins and a visual luminosity of 0.2% of that of the Sun.[14] However, a red dwarf such as Gliese 581 radiates primarily in the near infrared, with peak emission at a wavelength of roughly 830 nanometres (estimated using Wien's displacement law, which assumes the star radiates as a black body), so such an estimate will underestimate the star's total luminosity.[15] (For comparison, the peak emission of the Sun is roughly 530 nanometres, in the middle of the visible part of the spectrum). When radiation over the entire spectrum is taken into account (not just the part that humans are able to see), something known as the bolometric correction, this star has a bolometric luminosity 1.3% of the Sun's total luminosity.[2][14] A planet would need to be situated much closer to this star in order to receive a comparable amount of energy as the Earth. The region of space around a star where a planet would receive roughly the same energy as the Earth is sometimes termed the "Goldilocks Zone", or, more prosaically, the habitable zone. The extent of such a zone is not fixed and is highly specific for each planetary system.[16] Gliese 581 appears too massive to be a flare star which makes life more probable.[17] Gliese 581 does emit X-rays.[18]

[edit] Planetary system
At least six planets are believed to be orbiting Gliese 581. Gliese 581 b, approximately Neptune-sized, was discovered in August 2005 and was the fifth planet to be discovered around a red dwarf star. This inner planet is at least 16 times as massive as Earth (similar to Neptune's mass) and completes a full orbit of Gliese 581 in only 5.4 days.[2]


Three-planet Keplerian model of the Gliese 581 radial-velocity variations. The panels display the phase-folded curve of each of the planets, with points representing the observed radial velocities, after removing the effect of the other planets.Another planet, Gliese 581 c, was discovered in April 2007.[14] In their 2007 paper, Udry et al. assumed that if Gliese 581 c had a Earth-type composition, it would have a radius of 1.5R⊕, which would make it "the most Earth-like of all known exoplanets".[14]

A direct measurement of the radius cannot be taken because, viewed from Earth, the planet does not transit its sun. With a minimum mass of roughly five times Earth—or one third that of Neptune—Gliese 581 c orbits just inside of the habitable zone of its parent star.[19] The mean blackbody surface temperature has been estimated to lie between -3 °C (for a Venus-like albedo) and 40 °C (for an Earth-like albedo),[14] however, the temperatures could be much higher (about 500 degrees Celsius) due to a runaway greenhouse effect akin to that of Venus.[20] Some astronomers believe the system may have undergone planetary migration and Gliese 581 c may have formed beyond the frost line, with a composition similar to icy bodies like Ganymede. Gliese 581 c completes a full orbit in just under 13 days.[14]


The Gliese 581 planetary system orbits.Observations of the star also revealed a third planet, Gliese 581 d, with a mass of roughly 7 Earths, or half a Uranus, and an orbit of 66.8 Earth days.[14][21][22] It orbits just within the outer limit of the habitable zone of its star, which makes it a potential candidate for being able to support life.[12][20]

Discovery of a fourth planet, Gliese 581 e, was announced on 21 April 2009. This planet, at an estimated minimum mass of 1.9 Earths, is currently the lowest mass exoplanet identified around a normal star[clarification needed]. It takes 3.15 days to orbit Gliese 581.[12][22]

Dynamical simulations of the Gliese 581 system assuming that the orbits of planets b to d are coplanar show that the system becomes unstable if its component masses are more than 1.6 – 2 times the minimum mass. The upper limits on the masses of the planets are found to be 3.1, 30.4, 10.4 and 13.8 Earth masses for planets e, b, c and d respectively.[12]

On 29 September 2010, astronomers at Keck Observatory announced the discovery of Gliese 581 f and Gliese 581 g, both in nearly circular orbits. Gliese 581 g has a mass of 3 to 4 earth-masses, with an orbital period of 37 days, and is at a distance from Gliese 581 that is well within the star's habitable zone. The planet is predicted to be tidally locked, with one side of the planet always facing the star.[11][23]

The Gliese 581 system[12][11] Companion
(in order from star) Mass Semimajor axis
(AU) Orbital period
(days) Eccentricity
e 1.94 – 3.1 M⊕ 0.03 3.14942 ± 0.00045 unconstrained
b 15.65 – 30.4 M⊕ 0.04 5.36874 ± 0.00019 unconstrained
c 5.36 – 10.4 M⊕ 0.07 12.9292 ± 0.0047 0.17 ± 0.07
g ≥3.1 M⊕ 0.14601 ± 0.00014 36.562 ± 0.052 unconstrained
d 7.09 – 13.8 M⊕ 0.22 66.80 ± 0.14 0.38 ± 0.09
f ≥7.0 M⊕ 0.758 ± 0.015 433 ± 13 unconstrained

[edit] Message from Earth
In October 2008, members of the networking website Bebo beamed A Message From Earth, a high-power transmission at Gliese 581 c, using the RT-70 radio telescope belonging to the National Space Agency of Ukraine. This transmission is due to arrive in the Gliese 581 system's vicinity by the year 2029; the earliest possible arrival for a response, should there be one, would be in 2049.[24]

[edit] See also
Gliese 876
List of extrasolar planets
[edit] Notes
Note a: Note b: Gl 581 is classified as a BY Draconis variable in the General Catalogue of Variable Stars.[25] This catalog gives a maximum magnitude of 10.56 and minimum of magnitude 10.58 for a relatively low 20 mmag (0.020 magnitudes) variability.[26] For full data see data description and "The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars". Sternberg Astronomical Institute. www.sai.msu.su/groups/cluster/gcvs/gcvs/iii/iii.dat. In 1994 Edward Weis concluded that Gl 581, like half the 43 dwarf M stars he studied over a multi-year period, showed long term variability (and page 1137, Fig 1 shows Gl 581 had magnitude 10.58 in 1982 and between 10.57 and 10.56 from 1985 to 1990).[27] Bonfils noted in 2005 that "Gl 581 has been classified as a variable star (HO Lib), but its variability (Weis 1994) is only marginally significant. If real it would be on a time scale of several years, with short term variability being at most ∼0.006 mag."[28] Measurements by MOST showed short term variability of about 5 mmag (half a percent) over a period of a few weeks.[29]
[edit] References
^ a b c d e f V* HO Lib -- Variable Star, database entry, SIMBAD. Accessed on line August 21, 2008.
^ a b c d e Bonfils et al.; Forveille, T.; Delfosse, X.; Udry, S.; Mayor, M.; Perrier, C.; Bouchy, F.; Pepe, F. et al. (2005). "The HARPS search for southern extra-solar planets, VI. A Neptune-mass planet around the nearby M dwarf Gl 581" (PDF). Astronomy and Astrophysics 443: L15–L18. doi:10.1051/0004-6361:200500193. www.aanda.org/articles/aa/pdf/2005/45/aahh223.pdf. Retrieved 2009-04-27.
^ a b c van Leeuwen, F. (2007). "HIP 74995". Hipparcos, the New Reduction. Strasbourg Astronomical Observatory. webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=I/311/hip2&recno=74749. Retrieved 2008-08-16.
^ From apparent magnitude and parallax.
^ a b "Star: Gl 581". Extrasolar Planets Encyclopaedia. exoplanet.eu/star.php?st=Gl+581. Retrieved 2009-04-27. "0.31 Msun ... 8 (−1+3) Gyr"
^ a b c Bean, J. L.; Benedict, G. F.; Endl, M. (2006). "Metallicities of M Dwarf Planet Hosts from Spectral Synthesis". The Astrophysical Journal 653 (1): L65–L68. doi:10.1086/510527. adsabs.harvard.edu/abs/2006ApJ...653L..65B. Retrieved 2007-02-04.
^ Selsis 3.4 page 1382 "lower limit of the age that, considering the associated uncertainties, could be around 7 Gyr", "preliminary estimate", "should not be above 10-11 Gyr"
^ a b Entry 5594-1093-1, Tycho Catalogue, The Hipparcos and Tycho Catalogues, CDS ID I/239.
^ a b "The One Hundred Nearest Star Systems". Research Consortium on Nearby Stars. Georgia State University. January 1, 2009. www.chara.gsu.edu/~thenry/RECONS/TOP100.posted.htm. Retrieved 2010-06-04.
^ www.sciencedaily.com/releases/2010/09/100929170503.htm
^ a b c d e Vogt, Steven S.; Butler, R. Paul; Rivera, Eugenio J.; Haghighipour, Nader; Henry, Gregory W.; Williamson, Michael H. (2010-09-29). "The Lick-Carnegie Exoplanet Survey: A 3.1 M_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581". accepted by the Astrophysical Journal. arxiv.org/abs/1009.5733. Retrieved 2010-09-29.
^ a b c d e M. Mayor et al. (November 2009). "The HARPS search for southern extra-solar planets,XVIII. An Earth-mass planet in the GJ 581 planetary system". Astronomy and Astrophysics. doi:10.1051/0004-6361/200912172. Bibcode: 2009A&A...507..487M. obswww.unige.ch/~udry/Gl581_preprint.pdf.
^ news.yahoo.com/s/afp/20100929/sc_afp/usastronomyplanet;_ylt=Aq4ko85KMGYF.3DywUUJwFpxieAA;_ylu=X3oDMTE1dWlyZm04BHBvcwMxBHNlYwN5bi1jaGFubmVsBHNsawN1c3NjaWVudGlzdHM-
^ a b c d e f g Udry, S.; Bonfils, X.; Delfosse, X.; Forveille, T.; Mayor, M.; Perrier, C.; Bouchy, F.; Lovis, C.; Pepe, F.; Queloz, D.; Bertaux, J.-L. (2007). "The HARPS search for southern extra-solar planets. XI. Super-Earths (5 and 8 M⊕) in a 3-planet system" (PDF). Astronomy and Astrophysics 469 (3): L43 – L47. doi:10.1051/0004-6361:20077612. obswww.unige.ch/~udry/udry_preprint.pdf. Retrieved 2008-08-18.
^ "EDP Sciences". EDP Sciences. www.edpsciences.org/papers/aa/full/2005/45/aahh223/aahh223.html. Retrieved 2008-10-05.
^ Selsis et al.; Kasting, J. F.; Levrard, B.; Paillet, J.; Ribas, I.; Delfosse, X. (2007). "Habitable planets around the star Gl 581?". Astronomy and Astrophysics 476 (3): 1373–1387. doi:10.1051/0004-6361:20078091. cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2007A%26A...476.1373S&db_key=AST&nosetcookie=1.
^ www.universetoday.com/2009/04/21/nearly-earth-sized-planet-watery-world-spotted-near-another-star/
^ Schmitt JHMM, Fleming TA, Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Ap J. 450 (9): 392–400. doi:10.1086/176149. articles.adsabs.harvard.edu//full/1995ApJ...450..392S/0000395.000.html.
^ W. von Bloh, C. Bounama, M. thingyz, S. Franck (19 February 2008). [0712.3219] Habitability of Super-Earths: Gliese 581c and 581d. Arxiv.org. arxiv.org/abs/0712.3219. Retrieved 2008-10-05.
^ a b von Bloh et al. (2007). The Habitability of Super-Earths in Gliese 581. 476. Astronomy & Astrophysics. pp. 1365–1371. www.aanda.org/index.php?option=article&access=bibcode&bibcode=2007A%2526A...476.1365VPDF. Retrieved 2008-07-20.
^ "New 'super-Earth' found in space". BBC News. 25 April 2007. news.bbc.co.uk/1/hi/sci/tech/6589157.stm. Retrieved 2008-10-20.
^ a b Rincon, Paul; Amos, Jonathan (2009-04-21). "Lightest exoplanet is discovered". BBC. news.bbc.co.uk/1/hi/sci/tech/8008683.stm. Retrieved 2009-04-21.
^ "Keck Observatory discovers the first Goldilocks exoplanet". keckobservatory.org/news/keck_observatory_discovers_the_first_goldilocks_exoplanet/. Retrieved 2010-09-29.
^ "Zimbio Pilot - Gliese 581c". Zimbio.com. 2008-10-13. www.zimbio.com/pilot?ID=bwaIrlOhfhm&ZURL=/Gliese+581c/news&URL=http%3A%2F%2Fnews.google.com%2Fnews%2Furl%3Fsa%3DT%26ct%3Dus%2F3-0%26fd%3DR%26url%3Dhttp%3A%2F%2Fblogs.discovermagazine.com%2Fdiscoblog%2F2008%2F10%2F13%2Fbritney-pics-beamed-into-space-thus-far-aliens-remain-silent%2F%26cid%3D0%26ei%3DZ58MSeCgKpLmyASDtuz3AQ%26usg%3DAFQjCNFY_rY3wSipj2eD2pMLrI_lbcEWAg. Retrieved 2009-04-23.
^ Lopez-Morales, M.; Morrell, N. I.; Butler, R. P.; Seager, S. (2006). "Limits to Transits of the Neptune-mass planet orbiting Gl 581". Publications of the Astronomical Society of the Pacific 118. arxiv.org/abs/astro-ph/0609255. Retrieved 2009-04-23. "V* HO Lib ... BY Draconis". (page 2 of pre-print submitted 9 September 2006)
^ "General Catalogue of Variable Stars Query results". Sternberg Astronomical Institute, Moscow, Russia. Sternberg Astronomical Institute. www.sai.msu.su/groups/cluster/gcvs/cgi-bin/search.cgi?search=HO+Lib. Retrieved 2009-04-27.
^ Weis, Edward W. (March 1994). "Long term variability in dwarf M stars". American Astronomical Society 107 (3): 1138. doi:10.1086/116925. adsabs.harvard.edu/abs/1994AJ....107.1135W. Retrieved 2009-04-27.
^ Bonfils page L15
^ J. M. Matthews; others (March 2007). "MOST exoplanet system photometry" (PDF). pp. 80. nexsci.caltech.edu/workshop/2007/Matthews.pdf. Retrieved 2009-04-27.



The star Gliese 581.
Digital Sky Survey photo.
Observation data
Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation Libra
Right ascension 15h 19m 26.8250s[1]
Declination −07° 43′ 20.209″[1]
Apparent magnitude (V) 10.56 to 10.58a
Characteristics
Spectral type M3V[2]
B−V color index 1.61[1]
Variable type BYb
Astrometry

Radial velocity (Rv) −9.5 ± 0.5[1] km/s
Proper motion (μ) RA: −1233.51[3] mas/yr
Dec.: −94.52[3] mas/yr
Parallax (π) 160.91 ± 2.62[3] mas
Distance 20.3 ± 0.3 ly
(6.2 ± 0.1 pc)
Absolute magnitude (MV) 11.6[4]

Details

Mass 0.31[5] M☉
Radius 0.29[2] R☉
Surface gravity (log g) 4.92 ± 0.10[6]
Luminosity (bolometric) 0.013[2] L☉
Temperature 3,480 ± 48[6] K
Metallicity [M/H] = −0.33 ± 0.12[6]
Age 7 to 11 × 109[5][7] years

Other designations
HO Librae, HO Lib, BD−07°4003, GJ 581, HIP 74995, LFT 1195, LHS 394, LPM 564, LTT 6112, NLTT 39886, TYC 5594-1093-1, Wolf 562.[1][8]

en.wikipedia.org/wiki/Gliese_581