Turkish Astronomers Discover New Short Period Variable Star

Turkish Astronomers Discover New Short Period Variable Star
The field of the variable taken from the IST23 telescope on the night of February 2020, 40. In addition to variable and comparison stars, exoplanet host star XO-2 is also marked. Credits: Sağlam et al., 2022.

Astronomers from Istanbul University have reported the finding of a new short-period pulsating variable star during observations of the exoplanet host star XO-2 field. The newly detected object is most likely a Delta Scuti type variant with a vibration period of less than one hour. Discovery, June 29 arXiv.orgIt was explained in detail in an article published in .

Let us introduce the authors of the study to you;

Mustafa Turan Sağlam, Meryem Çörduk, Sinan Aliş, Görkem Özgül, Olcaytuğ Özgüllü, Fatih Erkam Göktürk, Rahmi Gündüz, Süleyman Fişek, F. Korhan Yelkenci, Eyüp Kaan Ülgen, Tolga Güver.

Fizikhaber As his family, we congratulate them. We would also like to state that we are excited to convey this success to our youth and all science lovers.

Let's move on to the content of their work;

Detecting and studying variable stars can yield important clues about stellar structure and evolution. Investigating the variables can also help to better understand the distance scale of the universe.

Delta Scuti stars are pulsating variables with spectral types A through F, named after the Delta Scuti variable in the constellation Scutum. They exhibit radial and non-radial vibrations covering periods ranging from 20 minutes to eight hours. Studying the vibrational behavior of Delta Scuti variables can help us improve our knowledge of the interior of stars.

Now, a team of astronomers led by Mustafa Turan Sağlam has found a new variant that appears to be of the Delta Scuti type. They used the Istanbul University Observatory's 0.4m Schmidt-Cassegrain telescope (IST40) to observe exoplanet host star XO-2 as part of a research program investigating transit timing changes. Extensive follow-up photometric observations of the newly found star were then made to confirm its variability.

Researchers state the following:

“We present the detection of a new variant in the field of exoplanet host star XO-2. The new variant was observed over 10 nights with different standard photometric filters as well as white light observations.”

The vibrational period of the new variant is measured at about 0.95 hours, while its mass is estimated to be between 1.5 and 1.7 solar masses. It was found that the variable is of A7 spectral type and has an effective temperature of about 7,725 K. These features are typical for Delta Scuti stars.

Brief Information on Variable Star Observations?

Eta Carinae, a photogenic variable star embedded in the Carinae Nebula
Variable stars are often analyzed using photometry, spectrophotometry, and spectroscopy. Measurements of brightness changes can be plotted to produce light curves. For regular variables, the variation period and amplitude can be determined very well; But for many variable stars, these amounts can change slowly over time, even from one period to the next. The peaks in the light curve are known as the maximum and the troughs as the minimum.

Amateur astronomers can do useful scientific work on variable stars by visually comparing the star to other fixed stars of known sizes in the same telescopic field of view. A visual light curve can be created by estimating the magnitude of the variable and noting the time of observation. The American Association of Variable Star Observers collects such observations from participants around the world and shares the data with the scientific community.

The following data is obtained from the light curve:

Are the brightness changes periodic, semi-periodic, irregular or unique?
What is the period of brightness fluctuations?
what is the shape of the light curve (symmetrical or not, angular or uniformly variable, does each cycle have only one or more minimums, etc.)?

If we go back to the content of the study;

In addition, the shape of the light curves of the newly detected variable and automatic classification based on machine learning algorithms support the Delta Scuti scenario. Astronomers calculate that the probability of this hypothesis being correct is around 78%.

The study also found that the studied star had a luminosity of about 6.93 solar luminosity and an absolute magnitude of about 2.76 in the V-band. Based on data from ESA's Gaia satellite, the distance to this variable is estimated to be about 5.613 light-years.

Summing up the results, the researchers noted that further observations of this variable are needed to definitively confirm the nature of this variable and shed more light on its vibrational behavior.

“Additional ground-based observations can be combined with TESS [Transiting Exoplanet Survey Satellite] brief cadence observations to perform a deeper study of the new variable,” the study authors wrote.

source: physorg

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