TY - JOUR
T1 - Looking for a pulse
T2 - A search for rotationally modulated radio emission from the hot Jupiter, τ BOÖTIS b
AU - Hallinan, G.
AU - Sirothia, S. K.
AU - Antonova, A.
AU - Ishwara-Chandra, C. H.
AU - Bourke, S.
AU - Doyle, J. G.
AU - Hartman, J.
AU - Golden, A.
PY - 2013/1/1
Y1 - 2013/1/1
N2 - Hot Jupiters have been proposed as a likely population of low-frequency radio sources due to electron cyclotron maser emission of similar nature to that detected from the auroral regions of magnetized solar system planets. Such emission will likely be confined to specific ranges of orbital/rotational phase due to a narrowly beamed radiation pattern. We report on GMRT 150 MHz radio observations of the hot Jupiter τ Boötis b, consisting of 40 hr carefully scheduled to maximize coverage of the planet's 79.5 hr orbital/rotational period in an effort to detect such rotationally modulated emission. The resulting image is the deepest yet published at these frequencies and leads to a 3σ upper limit on the flux density from the planet of 1.2 mJy, two orders of magnitude lower than predictions derived from scaling laws based on solar system planetary radio emission. This represents the most stringent upper limits for both quiescent and rotationally modulated radio emission from a hot Jupiter yet achieved and suggests that either (1) the magnetic dipole moment of τ Boötis b is insufficient to generate the surface field strengths of >50 G required for detection at 150 MHz or (2) Earth lies outside the beaming pattern of the radio emission from the planet.
AB - Hot Jupiters have been proposed as a likely population of low-frequency radio sources due to electron cyclotron maser emission of similar nature to that detected from the auroral regions of magnetized solar system planets. Such emission will likely be confined to specific ranges of orbital/rotational phase due to a narrowly beamed radiation pattern. We report on GMRT 150 MHz radio observations of the hot Jupiter τ Boötis b, consisting of 40 hr carefully scheduled to maximize coverage of the planet's 79.5 hr orbital/rotational period in an effort to detect such rotationally modulated emission. The resulting image is the deepest yet published at these frequencies and leads to a 3σ upper limit on the flux density from the planet of 1.2 mJy, two orders of magnitude lower than predictions derived from scaling laws based on solar system planetary radio emission. This represents the most stringent upper limits for both quiescent and rotationally modulated radio emission from a hot Jupiter yet achieved and suggests that either (1) the magnetic dipole moment of τ Boötis b is insufficient to generate the surface field strengths of >50 G required for detection at 150 MHz or (2) Earth lies outside the beaming pattern of the radio emission from the planet.
KW - planets and satellites: aurorae
KW - planets and satellites: detection
KW - planets and satellites: individual (τ Böotis b)
KW - planets and satellites: magnetic fields
KW - radio continuum: planetary systems
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U2 - 10.1088/0004-637X/762/1/34
DO - 10.1088/0004-637X/762/1/34
M3 - Article
AN - SCOPUS:84871304921
SN - 0004-637X
VL - 762
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 34
ER -