TY - JOUR

T1 - Derivation of the mass distribution of extrasolar planets with maxlima, a maximum likelihood algorithm

AU - Zucker, Shay

AU - Mazeh, Tsevi

PY - 2001

Y1 - 2001

N2 - We construct a maximum likelihood algorithm, MAXLIMA, to derive the mass distribution of the extrasolar planets when only the minimum masses are observed. The algorithm derives the distribution by solving a numerically stable set of equations and does not need any iteration or smoothing. Based on 50 minimum masses, MAXLIMA yields a distribution that is approximately flat in log M. The frequency drops off very sharply as masses go higher than 10 MJ although we suspect there is still a higher mass tail that extends up to probably 20 MJ. We estimate that 5% of the G stars in the solar neighborhood have planets in the range 1-10 MJ with periods shorter than 1500 days. For comparison we present the mass distribution of stellar companions in the range 100-1000 MJ, which is also approximately flat in log M. The two populations are separated by the "brown dwarf desert," a fact that strongly supports the idea that these are two distinct populations. Accepting this definite separation, we point out the conundrum concerning the similarities between the period, eccentricity, and even mass distribution of the two populations.

AB - We construct a maximum likelihood algorithm, MAXLIMA, to derive the mass distribution of the extrasolar planets when only the minimum masses are observed. The algorithm derives the distribution by solving a numerically stable set of equations and does not need any iteration or smoothing. Based on 50 minimum masses, MAXLIMA yields a distribution that is approximately flat in log M. The frequency drops off very sharply as masses go higher than 10 MJ although we suspect there is still a higher mass tail that extends up to probably 20 MJ. We estimate that 5% of the G stars in the solar neighborhood have planets in the range 1-10 MJ with periods shorter than 1500 days. For comparison we present the mass distribution of stellar companions in the range 100-1000 MJ, which is also approximately flat in log M. The two populations are separated by the "brown dwarf desert," a fact that strongly supports the idea that these are two distinct populations. Accepting this definite separation, we point out the conundrum concerning the similarities between the period, eccentricity, and even mass distribution of the two populations.

KW - Binaries: spectroscopic

KW - Methods: statistical

KW - Planetary systems

KW - Stars: low-mass, brown dwarfs

KW - Stars: statistics

UR - http://www.scopus.com/inward/record.url?scp=0001476770&partnerID=8YFLogxK

U2 - 10.1086/323866

DO - 10.1086/323866

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AN - SCOPUS:0001476770

SN - 0004-637X

VL - 562

SP - 1038

EP - 1044

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2 PART II

ER -