C.D.S. - SIMBAD4 rel 1.7 - 2020.04.08CEST19:49:57

2009A&A...494..391R - Astronomy and Astrophysics, volume 494, 391-397 (2009/1-4)

A cool starspot or a second transiting planet in the TrES-1 system?.


Abstract (from CDS):

We investigate the origin of a flux increase found during a transit of TrES-1, observed with the HST (Hubble Space Telescope). This feature in the HST light curve cannot be attributed to noise and is supposedly a dark area on the stellar surface of the host star eclipsed by TrES-1 during its transit. We investigate the likelihood of two possible hypotheses for its origin. A starspot or a second transiting planet. We made use of several transit observations of TrES-1 from space with the HST and from ground with the IAC 80-cm telescope (IAC-80). On the basis of these observations we did a statistical study of flux variations in each of the observed events to investigate whether similar flux increases are present in other parts of the data set. The HST observation presents a single clear flux rise during a transit, whereas the ground observations lead to detecting two such events but with low significance. In the case of having observed a starspot in the HST data, assuming a central impact between the spot and TrES-1, we would obtain a lower limit for the spot radius of 42000km. For this radius the spot temperature would be 4690K, 560K lower then the stellar surface of 5250 K. For a putative second transiting planet, we can set a lower limit for its radius at 0.37RJ and for periods of less than 10.5-days, we can set an upper limit at 0.72RJ. Assuming a conventional interpretation, this HST observation then constitutes the detection of a starspot. Alternatively, this flux rise might also be caused by an additional transiting planet. The true nature of the origin can be revealed if a wavelength dependency of the flux rise can be shown or discarded with higher certainty. Additionally, the presence of a second planet can be detected by radial velocity measurements.

Abstract Copyright:

Journal keyword(s): starspots - planetary systems

Status at CDS:  

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 TrES-1 Pl 19 04 09.8516024106 +36 37 57.445911611           ~ 310 1
2 TYC 2652-1324-1 V* 19 04 09.8516024106 +36 37 57.445911611   12.35 11.42     K0V 101 1
3 HD 189733 BY* 20 00 43.7130382888 +22 42 39.071811263 9.241 8.578 7.648 7.126 6.68 K0V+M4V 708 1
4 V* V376 Peg EP* 22 03 10.7729598762 +18 53 03.548248479   8.21 7.63     F9V 987 1

    Equat.    Gal    SGal    Ecl

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