TWO PLANETARY COMPANIONS AROUND THE K7 DWARF GJ 221: A HOT SUPER-EARTH AND A CANDIDATE IN THE SUB-SATURN DESERT RANGE

被引:11
作者
Arriagada, Pamela [1 ,2 ]
Anglada-Escude, Guillem [2 ,3 ]
Butler, R. Paul [2 ]
Crane, Jeffrey D. [4 ]
Shectman, Stephen A. [4 ]
Thompson, Ian [4 ]
Wende, Sebastian [3 ]
Minniti, Dante [1 ,5 ]
机构
[1] Pontificia Univ Catolica Chile, Dept Astron, Santiago 22, Chile
[2] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 USA
[3] Univ Gottingen, Inst Astrophys, D-37077 Gottingen, Germany
[4] Observ Carnegie Inst Washington, Pasadena, CA 91101 USA
[5] Univ Andres Bello, Dept Ciencias Fis, Santiago, Chile
关键词
planetary systems; stars:; individual; (GJ; 221; BD-061339); STAR SPECTROSCOPIC SURVEY; LOW-MASS STARS; M-CIRCLE-PLUS; RADIAL-VELOCITY; CHROMOSPHERIC ACTIVITY; DETERMINISTIC MODEL; PRECISION; SEARCH; ASTROMETRY; SYSTEM;
D O I
10.1088/0004-637X/771/1/42
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We report two low-mass companions orbiting the nearby K7 dwarf GJ 221 that have emerged from reanalyzing 4.4 yr of publicly available HARPS spectra complemented with 2 years of high-precision Doppler measurements with Magellan/PFS. The HARPS measurements alone contain the clear signal of a low-mass companion with a period of 125 days and a minimum mass of 53.2 M-circle plus (GJ 221b), falling in a mass range where very few planet candidates have been found (sub-Saturn desert). The addition of 17 PFS observations allows the confident detection of a second low-mass companion (6.5M(circle plus)) in a hot orbit (3.87 day period, GJ 221c). Spectroscopic and photometric calibrations suggest that GJ 221 is slightly depleted ([Fe/H]similar to-0.1) compared to the Sun, so the presence of two low-mass companions in the system confirms the trend that slightly reduced stellar metallicity does not prevent the formation of planets in the super-Earth to sub-Saturn mass regime.
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页数:9
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