Early-type stars: Most favorable targets for astrometrically detectable planets in the habitable zone

Andrew Gould, Eric B. Ford, Debra A. Fischer

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Early-type stars appear to be a difficult place to look for planets astrometrically. First, they are relatively heavy, and for fixed planetary mass the astrometric signal falls inversely as the stellar mass. Second, they are relatively rare (and so tend to be more distant), and for fixed orbital separation the astrometric signal falls inversely as the distance. Nevertheless, because early-type stars are relatively more luminous, their habitable zones are at larger semimajor axis. Since astrometric signal scales directly as orbital size, this gives early-type stars a strong advantage, which more than compensates for the other two factors. Using the Hipparcos Catalog, we show that F and A stars constitute the majority of viable targets for astrometric searches for planets with semimajor axes currently in the habitable zone. Thus, astrometric surveys are complementary to transit searches, which are primarily sensitive to habitable planets around late-type stars.

Original languageEnglish (US)
Pages (from-to)L155-L158
JournalAstrophysical Journal
Volume591
Issue number2 II
DOIs
StatePublished - Jul 10 2003

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planets
planet
stars
F stars
planetary mass
A stars
orbitals
transit
stellar mass
catalogs

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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abstract = "Early-type stars appear to be a difficult place to look for planets astrometrically. First, they are relatively heavy, and for fixed planetary mass the astrometric signal falls inversely as the stellar mass. Second, they are relatively rare (and so tend to be more distant), and for fixed orbital separation the astrometric signal falls inversely as the distance. Nevertheless, because early-type stars are relatively more luminous, their habitable zones are at larger semimajor axis. Since astrometric signal scales directly as orbital size, this gives early-type stars a strong advantage, which more than compensates for the other two factors. Using the Hipparcos Catalog, we show that F and A stars constitute the majority of viable targets for astrometric searches for planets with semimajor axes currently in the habitable zone. Thus, astrometric surveys are complementary to transit searches, which are primarily sensitive to habitable planets around late-type stars.",
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Early-type stars : Most favorable targets for astrometrically detectable planets in the habitable zone. / Gould, Andrew; Ford, Eric B.; Fischer, Debra A.

In: Astrophysical Journal, Vol. 591, No. 2 II, 10.07.2003, p. L155-L158.

Research output: Contribution to journalArticle

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