Retired A Stars and Their Companions. IV. Seven Jovian Exoplanets from Keck Observatory
Retired A Stars and Their Companions. IV. Seven Jovian Exoplanets from Keck Observatory
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退休 A 明星和他们的同伴。
DOI：
10.1086/653809
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发表时间：
2010
影响因子：
3.5
通讯作者：
H. Isaacson
中科院分区：
文献类型：
--
作者：
J. Johnson;A. Howard;B. Bowler;G. Henry;G. Marcy;J. Wright;D. Fischer;H. Isaacson
我们报告了凯克天文台对七个亚巨星的精确多普勒测量。这七颗恒星的视向速度与开普勒轨道上的行星质量伴星一致。主星的质量范围为1.1≤M -百科/M⊙≤1.9，半径3.4≤R -百科/R⊙≤6.1，金属丰度-0.21≤[Fe/H]≤+0.26。这些行星的质量都比木星大（mpsin1bb101mjp），它们的半长轴为bb11au。我们展示了费尔伯恩天文台的T3 0.4 m APT对其中五个目标的毫级光度测定。我们的监测显示这些恒星在光度上是稳定的，进一步加强了对观测到的径向速度变化的解释。迄今发现的原a型恒星周围行星的轨道特征与光谱型为F、G和K的矮星周围行星的轨道特征非常不同，这表明行星的形成和迁移是恒星质量的敏感函数。其中三个行星系统显示出长期线性趋势的证据，表明存在其他遥远的伴星。这些趋势，加上高质量的行星和增加的发生率，表明a型恒星是直接成像调查非常有希望的目标。
We report precise Doppler measurements of seven subgiants from Keck Observatory. All seven stars show variability in their radial velocities consistent with planet-mass companions in Keplerian orbits. The host stars have masses ranging from 1.1 ≤ M⋆/M⊙ ≤ 1.9, radii 3.4 ≤ R⋆/R⊙ ≤ 6.1, and metallicities -0.21 ≤ [Fe/H] ≤ +0.26. The planets are all more massive than Jupiter (MP sin i > 1 MJup) and have semimajor axes a > 1 AU. We present millimagnitude photometry from the T3 0.4 m APT at Fairborn Observatory for five of the targets. Our monitoring shows these stars to be photometrically stable, further strengthening the interpretation of the observed radial velocity variability. The orbital characteristics of the planets thus far discovered around former A-type stars are very different from the properties of planets around dwarf stars of spectral type F, G, and K, and suggests that the formation and migration of planets is a sensitive function of stellar mass. Three of the planetary systems show evidence of long-term, linear trends indicative of additional distant companions. These trends, together with the high planet masses and increased occurrence rate, indicate that A-type stars are very promising targets for direct-imaging surveys.