<p>The paper demonstrates the spectroscopic and photometric capabilities of the Ultra-Violet Imaging Telescope (UVIT) to study T-Tauri stars (TTSs). We present the first UVIT/Far-UV (FUV) spectrum of a TTS, TW Hya. Based on C <span>iv</span> line luminosity, we estimated accretion luminosity (0.12±0.03 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$L_\odot $</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>L</mi> <mo>⊙</mo> </msub> </math></EquationSource> </InlineEquation>) and mass accretion rate (2.4±0.6 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\times $</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$10^{-8} M_\odot /yr$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>8</mn> </mrow> </msup> <msub> <mi>M</mi> <mo>⊙</mo> </msub> <mo stretchy="false">/</mo> <mi>y</mi> <mi>r</mi> </mrow> </math></EquationSource> </InlineEquation>) of TW Hya, and compared these values with the accretion luminosity (0.031±0.002 <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$L_\odot $</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>L</mi> <mo>⊙</mo> </msub> </math></EquationSource> </InlineEquation>) and mass accretion rate (0.62±0.04 <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$\times $</EquationSource> <EquationSource Format="MATHML"><math> <mo>×</mo> </math></EquationSource> </InlineEquation> <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$10^{-8} M_\odot /yr$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mn>10</mn> <mrow> <mo>-</mo> <mn>8</mn> </mrow> </msup> <msub> <mi>M</mi> <mo>⊙</mo> </msub> <mo stretchy="false">/</mo> <mi>y</mi> <mi>r</mi> </mrow> </math></EquationSource> </InlineEquation>) derived from spectral energy distribution (SED). From the SED, we derive best-fitted parameters for TW Hya: <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$T_{eff}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>T</mi> <mrow> <mi mathvariant="italic">eff</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> = 3900±50 K, radius = 1.2±0.03 <InlineEquation ID="IEq8"> <EquationSource Format="TEX">$R_\odot $</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>R</mi> <mo>⊙</mo> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq9"> <EquationSource Format="TEX">$\log \, g = 4.0$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>log</mo> <mspace width="0.166667em" /> <mi>g</mi> <mo>=</mo> <mn>4.0</mn> </mrow> </math></EquationSource> </InlineEquation> and equivalent black-body temperatures corresponding to accretion luminosity as 14100±25 K. The parameters of TW Hya derived from UVIT observations were found to be matched well with the literature. Comparison with International Ultraviolet Explorer (IUE) and Hubble Space Telescope (HST) spectra suggests that UVIT can be used to study the spectroscopic variability of young stars. This study proposes leveraging the FUV spectroscopic capabilities of UVIT to contribute to the advancement of upcoming UV spectroscopic missions, including the Indian Spectroscopic Imaging Space Telescope.</p>

UVIT/AstroSat observation of TW Hya

期刊论文
发表日期：

2026年7月3日

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Prasanta K. Nayak,
Mayank Narang,
P. Manoj,
D. K. Ojha,
U. S. Kamath,
Blesson Mathew,
T. Baug,
S. Vig,
S. Chandra,
G. Maheswar

摘要

The paper demonstrates the spectroscopic and photometric capabilities of the Ultra-Violet Imaging Telescope (UVIT) to study T-Tauri stars (TTSs). We present the first UVIT/Far-UV (FUV) spectrum of a TTS, TW Hya. Based on C iv line luminosity, we estimated accretion luminosity (0.12±0.03 $L_\odot $ $L_{⊙}$ ) and mass accretion rate (2.4±0.6 $\times $ $\times$ $10^{-8} M_\odot /yr$ $10^{- 8} M_{⊙} / y r$ ) of TW Hya, and compared these values with the accretion luminosity (0.031±0.002 $L_\odot $ $L_{⊙}$ ) and mass accretion rate (0.62±0.04 $\times $ $\times$ $10^{-8} M_\odot /yr$ $10^{- 8} M_{⊙} / y r$ ) derived from spectral energy distribution (SED). From the SED, we derive best-fitted parameters for TW Hya: $T_{eff}$ $T_{eff}$ = 3900±50 K, radius = 1.2±0.03 $R_\odot $ $R_{⊙}$ , $\log \, g = 4.0$ $log g = 4.0$ and equivalent black-body temperatures corresponding to accretion luminosity as 14100±25 K. The parameters of TW Hya derived from UVIT observations were found to be matched well with the literature. Comparison with International Ultraviolet Explorer (IUE) and Hubble Space Telescope (HST) spectra suggests that UVIT can be used to study the spectroscopic variability of young stars. This study proposes leveraging the FUV spectroscopic capabilities of UVIT to contribute to the advancement of upcoming UV spectroscopic missions, including the Indian Spectroscopic Imaging Space Telescope.