TY - JOUR
T1 - Two planetary companions around the K7 dwarf GJ 221
T2 - A hot super-earth and a candidate in the sub-saturn desert range
AU - Arriagada, Pamela
AU - Anglada-Escudé, Guillem
AU - Butler, R. Paul
AU - Crane, Jeffrey D.
AU - Shectman, Stephen A.
AU - Thompson, Ian
AU - Wende, Sebastian
AU - Minniti, Dante
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2013/7/1
Y1 - 2013/7/1
N2 - 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 ⊕ (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 (6.5 M ⊕) in a hot orbit (3.87 day period, GJ 221c). Spectroscopic and photometric calibrations suggest that GJ 221 is slightly depleted ([Fe/H] ∼ -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.
AB - 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 ⊕ (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 (6.5 M ⊕) in a hot orbit (3.87 day period, GJ 221c). Spectroscopic and photometric calibrations suggest that GJ 221 is slightly depleted ([Fe/H] ∼ -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.
KW - planetary systems
KW - stars: individual (GJ 221, BD-061339)
UR - http://www.scopus.com/inward/record.url?scp=84879399266&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/771/1/42
DO - 10.1088/0004-637X/771/1/42
M3 - Article
AN - SCOPUS:84879399266
SN - 0004-637X
VL - 771
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 42
ER -