%0 Journal Article %1 Vogt2010 %A Vogt, Steven S. %A Butler, R. Paul %A Rivera, Eugenio J. %A Haghighipour, Nader %A Henry, Gregory W. %A Williamson, Michael H. %D 2010 %J The Astrophysical Journal %K 2010 a:Butler a:Vogt gl581 habitability lick-carnegie-survey planets rocky %N 1 %P 44 %R 10.1088/0004-637X/723/1/954 %T The Lick-Carnegie Exoplanet Survey: A 3.1 M\_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581 %U http://stacks.iop.org/0004-637X/723/i=1/a=954?key=crossref.35aa2d303033b7c72f1c796330169273 http://arxiv.org/abs/1009.5733 %V 723 %X We present 11 years of HIRES precision radial velocities (RV) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS precision RVs. The velocity set now indicates 6 companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of \~94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the radial velocity variations. The combined data set strongly confirms the 5.37-day, 12.9-day, 3.15-day, and 67-day planets previously announced by Bonfils et al. (2005), Udry et al. (2007), and Mayor et al (2009). The observations also indicate a 5th planet in the system, GJ 581f, a minimum-mass 7.0 M\_Earth planet orbiting in a 0.758 AU orbit of period 433 days and a 6th planet, GJ 581g, a minimum-mass 3.1 M\_Earth planet orbiting at 0.146 AU with a period of 36.6 days. The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. That a system harboring a potentially habitable planet has been found this nearby, and this soon in the relatively early history of precision RV surveys, indicates that eta\_Earth, the fraction of stars with potentially habitable planets, is likely to be substantial. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood suggests that eta\_Earth could well be on the order of a few tens of percent. If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.

@article{Vogt2010, abstract = {We present 11 years of HIRES precision radial velocities (RV) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS precision RVs. The velocity set now indicates 6 companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of \~{}94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the radial velocity variations. The combined data set strongly confirms the 5.37-day, 12.9-day, 3.15-day, and 67-day planets previously announced by Bonfils et al. (2005), Udry et al. (2007), and Mayor et al (2009). The observations also indicate a 5th planet in the system, GJ 581f, a minimum-mass 7.0 M\_Earth planet orbiting in a 0.758 AU orbit of period 433 days and a 6th planet, GJ 581g, a minimum-mass 3.1 M\_Earth planet orbiting at 0.146 AU with a period of 36.6 days. The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. That a system harboring a potentially habitable planet has been found this nearby, and this soon in the relatively early history of precision RV surveys, indicates that eta\_Earth, the fraction of stars with potentially habitable planets, is likely to be substantial. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood suggests that eta\_Earth could well be on the order of a few tens of percent. If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.}, added-at = {2013-08-04T12:36:29.000+0200}, archiveprefix = {arXiv}, arxivid = {1009.5733}, author = {Vogt, Steven S. and Butler, R. Paul and Rivera, Eugenio J. and Haghighipour, Nader and Henry, Gregory W. and Williamson, Michael H.}, biburl = {https://www.bibsonomy.org/bibtex/2c9a886995dd048ba9ae305b001c8edad/danielcarrera}, doi = {10.1088/0004-637X/723/1/954}, eprint = {1009.5733}, file = {:home/daniel/Papers/Planets-GL581g/1011.ApJ - Vogt - The Lick-Carnegie exoplanet survey$\backslash$: A 3.1 Me planet in the HZ of the nearby M3V star GL 581.pdf:pdf}, interhash = {a8677578f77f76ac548ba6c917159c23}, intrahash = {c9a886995dd048ba9ae305b001c8edad}, issn = {0004-637X}, journal = {The Astrophysical Journal}, keywords = {2010 a:Butler a:Vogt gl581 habitability lick-carnegie-survey planets rocky}, month = sep, number = 1, pages = 44, timestamp = {2014-07-18T13:23:19.000+0200}, title = {{The Lick-Carnegie Exoplanet Survey: A 3.1 M\_Earth Planet in the Habitable Zone of the Nearby M3V Star Gliese 581}}, url = {http://stacks.iop.org/0004-637X/723/i=1/a=954?key=crossref.35aa2d303033b7c72f1c796330169273 http://arxiv.org/abs/1009.5733}, volume = 723, year = 2010 }