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Article Dans Une Revue The Astrophysical Journal Année : 2008

A Multisite Campaign to Measure Solar-Like Oscillations in Procyon. I. Observations, Data Reduction and Slow Variations

1 DASC - Danish AsteroSeismology Centre
2 SIfA - Sydney Institute for Astronomy
3 CAUP - Centro de Astrofísica da Universidade do Porto
4 Gemini Observatory [Southern Operations Center]
5 Instituut voor Sterrenkunde [Leuven]
6 ObsGE - Observatoire Astronomique de l'Université de Genève
7 EPFL Laboratoire d’astrophysique
8 McDonald Observatory
9 HAO - High Altitude Observatory
10 Leiden Observatory [Leiden]
11 ROB - Royal Observatory of Belgium = Observatoire Royal de Belgique
12 LSW - Landessternwarte Königstuhl [ZAH]
13 Department of Terrestrial Magnetism [Carnegie Institution]
14 AAO - Anglo-Australian Observatory
15 OAO - Okayama Astrophysical Observatory
16 NAOJ - National Astronomical Observatory of Japan
17 Global Edge Institute
18 TLS - Thüringer Landessternwarte Tautenburg
19 IAP - Institut d'Astrophysique de Paris
20 OP - Observatoire de Paris - Site de Paris
21 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
22 IAS - Institut d'astrophysique spatiale
23 CASSIOPEE - Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides
24 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
25 SA - Service d'aéronomie
26 OHP - Observatoire de Haute-Provence
27 OACT - INAF - Osservatorio Astrofisico di Catania
28 OAPD - INAF - Osservatorio Astronomico di Padova
29 OAC - INAF - Osservatorio Astronomico di Capodimonte
30 SUPA School of Physics and Astronomy [University of St Andrews]
François Bouchy
Jean-Loup Bertaux

Résumé

We have carried out a multisite campaign to measure oscillations in the F5 star Procyon A. We obtained high-precision velocity observations over more than three weeks with 11 telescopes, with almost continuous coverage for the central 10 days. This represents the most extensive campaign so far organized on any solar-type oscillator. We describe in detail the methods we used for processing and combining the data. These involved calculating weights for the velocity time series from the measurement uncertainties and adjusting them in order to minimize the noise level of the combined data. The time series of velocities for Procyon shows the clear signature of oscillations, with a plateau of excess power that is centered at 0.9 mHz and is broader than has been seen for other stars. The mean amplitude of the radial modes is 38:1 AE 1:3 cm s À1 (2.0 times solar), which is consistent with previous detections from the ground and by the WIRE spacecraft, and also with the upper limit set by the MOST spacecraft. The variation of the amplitude during the observing campaign allows us to estimate the mode lifetime to be 1:5 þ1:9 À0:8 days. We also find a slow variation in the radial velocity of Procyon, with good agreement between different telescopes. These variations are remarkably similar to those seen in the Sun, and we interpret them as being due to rotational modulation from active regions on the stellar surface. The variations appear to have a period of about 10 days, which presumably equals the stellar rotation period or, perhaps, half of it. The amount of power in these slow variations indicates that the fractional area of Procyon covered by active regions is slightly higher than for the Sun.
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Dates et versions

hal-00337555 , version 1 (10-07-2020)

Identifiants

Citer

Torben Arentoft, Hans Kjeldsen, Timothy R. Bedding, Michaël Bazot, Jørgen Christensen-Dalsgaard, et al.. A Multisite Campaign to Measure Solar-Like Oscillations in Procyon. I. Observations, Data Reduction and Slow Variations. The Astrophysical Journal, 2008, 687, pp.1180-1190. ⟨10.1086/592040⟩. ⟨hal-00337555⟩
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