VARIATION in the PRE-TRANSIT BALMER LINE SIGNAL AROUND the HOT JUPITER HD 189733B

P. Wilson Cauley, Seth Redfield, Adam G. Jensen, Travis S Barman

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

As followup to our recent detection of a pre-transit signal around HD 189733 b, we obtained full pre-transit phase coverage of a single planetary transit. The pre-transit signal is again detected in the Balmer lines but with variable strength and timing, suggesting that the bow shock geometry reported in our previous work does not describe the signal from the latest transit. We also demonstrate the use of the Ca ii H and K residual core flux as a proxy for the stellar activity level throughout the transit. A moderate trend is found between the pre-transit absorption signal in the 2013 data and the Ca ii H flux. This suggests that some of the 2013 pre-transit hydrogen absorption can be attributed to varying stellar activity levels. A very weak correlation is found between the Ca ii H core flux and the Balmer line absorption in the 2015 transit, hinting at a smaller contribution from stellar activity compared to the 2013 transit. We simulate how varying stellar activity levels can produce changes in the Balmer line transmission spectra. These simulations show that the strength of the 2013 and 2015 pre-transit signals can be reproduced by stellar variability. If the pre-transit signature is attributed to circumplanetary material, its evolution in time can be described by accretion clumps spiraling toward the star, although this interpretation has serious limitations. Further high-cadence monitoring at H is necessary to distinguish between true absorption by transiting material and short-term variations in the stellar activity level.

Original languageEnglish (US)
Article number20
JournalAstronomical Journal
Volume152
Issue number1
DOIs
StatePublished - Jul 1 2016

Fingerprint

transit
stellar activity
accretion
hydrogen
geometry
monitoring
simulation
bows
clumps
transmission lines
shock
time measurement
signatures
material
trends
stars

Keywords

  • planets and satellites: atmospheres
  • planets and satellites: gaseous planets
  • planets and satellites: magnetic fields
  • stars: activity

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

VARIATION in the PRE-TRANSIT BALMER LINE SIGNAL AROUND the HOT JUPITER HD 189733B. / Wilson Cauley, P.; Redfield, Seth; Jensen, Adam G.; Barman, Travis S.

In: Astronomical Journal, Vol. 152, No. 1, 20, 01.07.2016.

Research output: Contribution to journalArticle

Wilson Cauley, P. ; Redfield, Seth ; Jensen, Adam G. ; Barman, Travis S. / VARIATION in the PRE-TRANSIT BALMER LINE SIGNAL AROUND the HOT JUPITER HD 189733B. In: Astronomical Journal. 2016 ; Vol. 152, No. 1.
@article{6f7e3257443b4bc381a5583d82e01399,
title = "VARIATION in the PRE-TRANSIT BALMER LINE SIGNAL AROUND the HOT JUPITER HD 189733B",
abstract = "As followup to our recent detection of a pre-transit signal around HD 189733 b, we obtained full pre-transit phase coverage of a single planetary transit. The pre-transit signal is again detected in the Balmer lines but with variable strength and timing, suggesting that the bow shock geometry reported in our previous work does not describe the signal from the latest transit. We also demonstrate the use of the Ca ii H and K residual core flux as a proxy for the stellar activity level throughout the transit. A moderate trend is found between the pre-transit absorption signal in the 2013 data and the Ca ii H flux. This suggests that some of the 2013 pre-transit hydrogen absorption can be attributed to varying stellar activity levels. A very weak correlation is found between the Ca ii H core flux and the Balmer line absorption in the 2015 transit, hinting at a smaller contribution from stellar activity compared to the 2013 transit. We simulate how varying stellar activity levels can produce changes in the Balmer line transmission spectra. These simulations show that the strength of the 2013 and 2015 pre-transit signals can be reproduced by stellar variability. If the pre-transit signature is attributed to circumplanetary material, its evolution in time can be described by accretion clumps spiraling toward the star, although this interpretation has serious limitations. Further high-cadence monitoring at H is necessary to distinguish between true absorption by transiting material and short-term variations in the stellar activity level.",
keywords = "planets and satellites: atmospheres, planets and satellites: gaseous planets, planets and satellites: magnetic fields, stars: activity",
author = "{Wilson Cauley}, P. and Seth Redfield and Jensen, {Adam G.} and Barman, {Travis S}",
year = "2016",
month = "7",
day = "1",
doi = "10.3847/0004-6256/152/1/20",
language = "English (US)",
volume = "152",
journal = "Astronomical Journal",
issn = "0004-6256",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - VARIATION in the PRE-TRANSIT BALMER LINE SIGNAL AROUND the HOT JUPITER HD 189733B

AU - Wilson Cauley, P.

AU - Redfield, Seth

AU - Jensen, Adam G.

AU - Barman, Travis S

PY - 2016/7/1

Y1 - 2016/7/1

N2 - As followup to our recent detection of a pre-transit signal around HD 189733 b, we obtained full pre-transit phase coverage of a single planetary transit. The pre-transit signal is again detected in the Balmer lines but with variable strength and timing, suggesting that the bow shock geometry reported in our previous work does not describe the signal from the latest transit. We also demonstrate the use of the Ca ii H and K residual core flux as a proxy for the stellar activity level throughout the transit. A moderate trend is found between the pre-transit absorption signal in the 2013 data and the Ca ii H flux. This suggests that some of the 2013 pre-transit hydrogen absorption can be attributed to varying stellar activity levels. A very weak correlation is found between the Ca ii H core flux and the Balmer line absorption in the 2015 transit, hinting at a smaller contribution from stellar activity compared to the 2013 transit. We simulate how varying stellar activity levels can produce changes in the Balmer line transmission spectra. These simulations show that the strength of the 2013 and 2015 pre-transit signals can be reproduced by stellar variability. If the pre-transit signature is attributed to circumplanetary material, its evolution in time can be described by accretion clumps spiraling toward the star, although this interpretation has serious limitations. Further high-cadence monitoring at H is necessary to distinguish between true absorption by transiting material and short-term variations in the stellar activity level.

AB - As followup to our recent detection of a pre-transit signal around HD 189733 b, we obtained full pre-transit phase coverage of a single planetary transit. The pre-transit signal is again detected in the Balmer lines but with variable strength and timing, suggesting that the bow shock geometry reported in our previous work does not describe the signal from the latest transit. We also demonstrate the use of the Ca ii H and K residual core flux as a proxy for the stellar activity level throughout the transit. A moderate trend is found between the pre-transit absorption signal in the 2013 data and the Ca ii H flux. This suggests that some of the 2013 pre-transit hydrogen absorption can be attributed to varying stellar activity levels. A very weak correlation is found between the Ca ii H core flux and the Balmer line absorption in the 2015 transit, hinting at a smaller contribution from stellar activity compared to the 2013 transit. We simulate how varying stellar activity levels can produce changes in the Balmer line transmission spectra. These simulations show that the strength of the 2013 and 2015 pre-transit signals can be reproduced by stellar variability. If the pre-transit signature is attributed to circumplanetary material, its evolution in time can be described by accretion clumps spiraling toward the star, although this interpretation has serious limitations. Further high-cadence monitoring at H is necessary to distinguish between true absorption by transiting material and short-term variations in the stellar activity level.

KW - planets and satellites: atmospheres

KW - planets and satellites: gaseous planets

KW - planets and satellites: magnetic fields

KW - stars: activity

UR - http://www.scopus.com/inward/record.url?scp=84978258163&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84978258163&partnerID=8YFLogxK

U2 - 10.3847/0004-6256/152/1/20

DO - 10.3847/0004-6256/152/1/20

M3 - Article

AN - SCOPUS:84978258163

VL - 152

JO - Astronomical Journal

JF - Astronomical Journal

SN - 0004-6256

IS - 1

M1 - 20

ER -